In sub-confluent primary Schwann cells, we found that merlin binds to paxillin and mediates merlin localization at the plasma membrane and association with beta1-integrin and ErbB2, modifying the organization of the actin cytoskeleton in a cell density dependent manner.

In sub-confluent primary Schwann cells, we found that merlin binds to paxillin and mediates merlin localization at the plasma membrane and association with beta1-integrin and ErbB2, modifying the organization of the actin cytoskeleton in a cell density dependent manner.

FAK silencing decreased schwannoma cell proliferation and was associated with increased levels of total and nuclear p53.

In a similar fashion, NF2 mutations increased the resistance to dihydrofolate reductase inhibitors methotrexalate and pyremethamine as well as the JNK inhibitor JNK-9L.

Furthermore, it was shown that overactive PAK and LIMK pathway activity contributed to cell proliferation through cofilin phosphorylation and auroraA activation.

Interestingly, it was shown that schwannoma cells release insulin like growth factor binding protein 1 which in beta1-integrin dependent manner activates Src and FAK signaling.

Interestingly, it was shown that schwannoma cells release insulin like growth factor binding protein 1 which in beta1-integrin dependent manner activates Src and FAK signaling.

Moreover, neuregulin survival signaling through the ErbB2 and ErbB3 receptor activates PI3K in rat Schwann cells through the activation of Akt and inhibition of Bad, a pro apoptotic Blc-2 family protein.

ErbB2 activation in mouse Nf2 deficient spinal cord neural progenitor cells was shown to be caused by Rac mediated retention of the receptor at the plasma membrane.

Silencing DCAF1 in Meso-33, merlin deficient mesothelioma cells reduced their proliferation by arresting the cell cycle in G1 phase.

Significantly, silencing of DCAF1 in schwannoma cells isolated from NF2 patients also reduced their proliferation.

Silencing DCAF1 in Meso-33, merlin deficient mesothelioma cells reduced their proliferation by arresting the cell cycle in G1 phase.

Furthermore, Amot silencing attenuated Rac1 and Ras and MAPK signaling pathway.

Silencing of Amot in Nf2 -/- Schwann cells (SC4) selectively reduced cell proliferation because it did not change the proliferation rate of SC4 with merlin re-expression.

Furthermore, Amot silencing attenuated Rac1 and Ras and MAPK signaling pathway.

Furthermore, Amot silencing attenuated Rac1 and Ras and MAPK signaling pathway.

In various cell types, the binding of hyaluronan to CD44 stimulates Tiam1 dependent Rac1 signaling and cytoskeleton mediated tumor cell migration.

In various cell types, the binding of hyaluronan to CD44 stimulates Tiam1 dependent Rac1 signaling and cytoskeleton mediated tumor cell migration.

First, protein kinase C potentiated phosphatase inhibitor (CPI-17), which is frequently overexpressed in mesothelioma tumors, inhibits merlin phosphatase MYPT1-PP1delta, providing one potential pathway by which merlin 's tumor suppressor function might be inactivated through maintenance of phosphorylation at Ser518.

First, protein kinase C potentiated phosphatase inhibitor (CPI-17), which is frequently overexpressed in mesothelioma tumors, inhibits merlin phosphatase MYPT1-PP1delta, providing one potential pathway by which merlin 's tumor suppressor function might be inactivated through maintenance of phosphorylation at Ser518.

In various cell types, the binding of hyaluronan to CD44 stimulates Tiam1 dependent Rac1 signaling and cytoskeleton mediated tumor cell migration.

Finally, a recent meningioma study of 73 patients found a high incidence of TERT promoter activating mutations in meningiomas undergoing malignant transformation in both NF2-related and sporadic meningiomas, whereas no TERT mutations were found in benign tumors.

We recently showed that PI3K inhibition in merlin deficient mouse Schwann cells selectively decreased their proliferation.

In primary rat Schwann cells, CD44 was shown to constitutively associate with the heterodimer receptor tyrosine kinase ErbB2 and ErbB3 and CD44 enhanced neuregulin induced ErbB2 activating phosphorylation.

Moreover, neuregulin survival signaling through the ErbB2 and ErbB3 receptor activates PI3K in rat Schwann cells through the activation of Akt and inhibition of Bad, a pro apoptotic Blc-2 family protein.

In the canonical hippo pathway, mammalian Ste20 like kinases (Mst1/2; hippo homolog) phosphorylate large tumor suppressor kinases (LATS 1/2), which in turn phosphorylate and inactivate YAP and TAZ, blocking their role as TEAD and MEAD transcription factor co-activators.

SOS is a GEF that activates Ras by catalyzing the nucleotide exchange.

The data suggest that in hepatocytes merlin is functionally linked to the hippo pathway and acts upstream Mst1/2 by recruiting LATS to the membrane comparable to what has been shown in FH912 Schwann cell line.

Translocation of merlin to the nucleus allows merlin to bind and inhibit the E3 ubiquitin ligase CRL4 DCAF1 ( D DB1- and C ul4- A ssociated F actor 1) ( xref , xref ).

Translocation of merlin to the nucleus allows merlin to bind and inhibit the E3 ubiquitin ligase CRL4 DCAF1 (DDB1- and Cul4 Associated Factor 1).

For example, in confluent human umbilical vein endothelial cells, merlin suppressed recruitment of Rac to the plasma membrane, and its silencing promoted recruitment of Rac1 to sites of extracellular matrix adhesion, and promoted cell growth ( xref ).

Previously, we showed that activation of ErbB2/ErbB3 receptors in primary rat Schwann cells by neuregulin-1 induced merlin phosphorylation at Ser518 via PKA ( xref ).

Notably, NF2 transfection into these cells induced YAP1 phosphorylation at Ser127, YAP1 retention in the cytoplasm and consequent reduction of YAP1 nuclear localization.

Previously, we showed that activation of ErbB2 and ErbB3 receptors in primary rat Schwann cells by neuregulin-1 induced merlin phosphorylation at Ser518 via PKA.

Previously, we showed that activation of ErbB2 and ErbB3 receptors in primary rat Schwann cells by neuregulin-1 induced merlin phosphorylation at Ser518 via PKA.

Previously, we showed that activation of ErbB2 and ErbB3 receptors in primary rat Schwann cells by neuregulin-1 induced merlin phosphorylation at Ser518 via PKA.

We reported that merlin associates with beta 1 -integrin in primary Schwann cells and undifferentiated Schwann cell and neuron co-cultures, and in primary Schwann cell cultures, laminin-1 stimulated integrin signaled though PAK1 and caused merlin Ser518 phosphorylation and inactivation of its tumor suppressor function.

Merlin is phosphorylated at Ser10, Thr230 and Ser315 by Akt (also known as protein kinase B, PKB) and controls merlin’s proteasome-mediated degradation by ubiquitination to prevent its interaction with binding partners ( xref , xref ).

Merlin is phosphorylated at Ser10, Thr230 and Ser315 by Akt (also known as protein kinase B, PKB) and controls merlin 's proteasome mediated degradation by ubiquitination to prevent its interaction with binding partners.

Merlin is phosphorylated at Ser10, Thr230 and Ser315 by Akt (also known as protein kinase B, PKB) and controls merlin 's proteasome mediated degradation by ubiquitination to prevent its interaction with binding partners.

Merlin is phosphorylated at Ser10, Thr230 and Ser315 by Akt (also known as protein kinase B, PKB) and controls merlin’s proteasome-mediated degradation by ubiquitination to prevent its interaction with binding partners ( xref , xref ).

Merlin is phosphorylated at Ser10, Thr230 and Ser315 by Akt (also known as protein kinase B, PKB) and controls merlin’s proteasome-mediated degradation by ubiquitination to prevent its interaction with binding partners ( xref , xref ).

Merlin is phosphorylated at Ser10, Thr230 and Ser315 by Akt (also known as protein kinase B, PKB) and controls merlin 's proteasome mediated degradation by ubiquitination to prevent its interaction with binding partners.

Loss of merlin results in integrin mediated activation of mTORC1 through PAK1, which promotes cell cycle progression by inducing translation of cyclin-D1 mRNA and cyclin-D1 expression.

Loss of merlin in mesotheliomas has been linked not only to increased proliferation, but also increased invasiveness, spreading and migration.

Adenoviral transduction of NF2 in Meso-17 and Meso-25 cell lines decreased invasion through Matrigel membranes compared to cells transduced with empty vector.

Second, similar to NF2 schwannomas, mesothelioma cells with NF2 inactivation, exhibit activated PAK1 and AKT, and re-expression of merlin in merlin-null human mesothelioma cells (Meso-17) decreases PAK1 activity.

Soon after merlin was cloned, evidence that merlin inhibits another important member of the Rho GTPases family, Ras, was reported in v-Ha-Ras-transformed NIH3T3cells in which merlin overexpression counteracted the oncogenic role of Ras.

Merlin re-expression in Nf2 -/- Schwann cells similarly reduced the transport of growth factor receptors ErbB2 and ErbB3, insulin like growth factor 1 receptor (IGF1R) and platelet derived growth factor receptor (PDGFR).

Merlin re-expression in Nf2 -/- Schwann cells similarly reduced the transport of growth factor receptors ErbB2 and ErbB3, insulin like growth factor 1 receptor (IGF1R) and platelet derived growth factor receptor (PDGFR).

In sum, multiple lines of evidence have established a feedback regulation loop with merlin being phosphorylated at Ser518 (growth permissive form) via activated Rho small GTPases Rac1 and Cdc42 through PAK, and in turn, merlin associating with PAK to inhibit Rac1 and Cdc42 signaling (XREF_FIG).

Collectively, these results indicate that merlin inhibits cell growth by contact inhibition in part by binding CD44 and negatively regulating CD44 function (XREF_FIG).

Merlin inactivation of Src signaling was also shown in CNS glial cells, where merlin competitively inhibits Src binding to ErbB2 thereby preventing ErbB2 mediated Src phosphorylation and downstream mitogenic signaling.

In the NF2 -/- breast cancer MDA-MB-231 cell line, merlin re-expression inhibited YAP and TEAD activity that was eliminated by LATS1/2 silencing.

Loss of merlin results in integrin mediated activation of mTORC1 through PAK1, which promotes cell cycle progression by inducing translation of cyclin-D1 mRNA and cyclin-D1 expression.

Loss of merlin activated mTORC1 signaling independently of Akt or ERK in these tumor cells; however, the molecular mechanism connecting merlin loss to mTORC1 activation remains to be elucidated.

Loss of merlin activated mTORC1 signaling independently of Akt or ERK in these tumor cells; however, the molecular mechanism connecting merlin loss to mTORC1 activation remains to be elucidated.

Furthermore, merlin overexpression in Tr6BC1 mouse schwannoma cells inhibited the binding of fluorescein labeled hyaluronan to CD44 and inhibited subcutaneous tumor growth in immunocompromised mice, and overexpression of a merlin mutant lacking the CD44 binding domain was unable to inhibit schwannoma growth.

Further studies showed that wild-type merlin is transported throughout the cell by microtubule motors and merlin mutants or depletion of the microtubule motor kinesin-1 suppressed merlin transport and was associated with accumulation of yorkie, a Drosophila homolog of the hippo pathway transcriptional co-activator Yes associated protein (YAP), in the nucleus.

In a similar fashion, NF2 mutations increased the resistance to dihydrofolate reductase inhibitors methotrexalate and pyremethamine as well as the JNK inhibitor JNK-9L.

The disrupted cell-contact inhibition signaling and merlin phosphorylation correlated with increased expression of NOTCH1 and its downstream target gene, HES1, which represses the transcription factor E2F in cell-contact growth arrest.

Binding of merlin unphosphorylated at Ser518 with the cytoplasmic tail of CD44 mediates contact inhibition at high cell density.

Loss of merlin activated mTORC1 signaling independently of Akt or ERK in these tumor cells; however, the molecular mechanism connecting merlin loss to mTORC1 activation remains to be elucidated.

First, protein kinase C potentiated phosphatase inhibitor (CPI-17), which is frequently overexpressed in mesothelioma tumors, inhibits merlin phosphatase MYPT1-PP1delta, providing one potential pathway by which merlin 's tumor suppressor function might be inactivated through maintenance of phosphorylation at Ser518.

First, protein kinase C potentiated phosphatase inhibitor (CPI-17), which is frequently overexpressed in mesothelioma tumors, inhibits merlin phosphatase MYPT1-PP1delta, providing one potential pathway by which merlin 's tumor suppressor function might be inactivated through maintenance of phosphorylation at Ser518.

Loss of merlin results in integrin mediated activation of mTORC1 through PAK1, which promotes cell cycle progression by inducing translation of cyclin-D1 mRNA and cyclin-D1 expression.

HDAC inhibitors disrupt the PP1-HDAC interaction facilitating Akt dephosphorylation and decrease human meningioma and schwannoma cell proliferation and schwannoma growth in an allograft model and meningioma growth in an intracranial xenograft model.

The mTORC1 inhibitor rapamycin selectively inhibited proliferation of seven merlin-null mesothelioma cell lines, but not merlin positive cell lines, suggesting a potential pharmacological target for merlin deficient mesotheliomas.

Merlin expression in Meso-17 and Meso-25 cells decreased FAK Tyr397 phosphorylation and consequently disrupted FAK-Src and PI3K interaction, providing a mechanism for the observed enhancement of invasion and spreading caused by merlin inactivation.

Accordingly, merlin was shown to reduce the levels of ErbB2 and ErbB3 receptor levels at the plasma membrane.

Accordingly, merlin was shown to reduce the levels of ErbB2 and ErbB3 receptor levels at the plasma membrane.

Accordingly, merlin was shown to reduce the levels of ErbB2 and ErbB3 receptor levels at the plasma membrane.

In sub-confluent primary Schwann cells, we found that merlin binds to paxillin and mediates merlin localization at the plasma membrane and association with beta1-integrin and ErbB2, modifying the organization of the actin cytoskeleton in a cell density dependent manner.

In sub-confluent primary Schwann cells, we found that merlin binds to paxillin and mediates merlin localization at the plasma membrane and association with β1-integrin and ErbB2, modifying the organization of the actin cytoskeleton in a cell density-dependent manner ( xref ).

Moreover, in cultured Schwann cells, merlin interaction with Amot was demonstrated by co-immunoprecipitation of the endogenous proteins.

Moreover, in cultured Schwann cells, merlin interaction with Amot was demonstrated by co-immunoprecipitation of the endogenous proteins ( xref ).

Merlin-Amot interaction was required for merlin regulation of mitogenic MAPK signaling.

Moreover, co-immunoprecipitation experiments revealed that merlin interacts with YAP1, although the interaction is not direct.

Moreover, co-immunoprecipitation experiments revealed that merlin interacts with YAP1, although the interaction is not direct ( xref ).

Studies in human meningioma tumors and in paired cell lines—KY21MG1 or MENII-1 meningioma cell lines and AC1 arachnoidal cells—demonstrated that merlin loss was associated with increased YAP expression and nuclear localization.

Amot-p130 isoform bound to the WW domains of YAP and blocked LATS1 access to YAP.

The activation of Rac1 through CD44 was identified via the interaction of CD44 with Tiam-1, a Rac1 guanine nucleotide exchange factor (GEF) that catalyzes the replacement of the tightly-bound GDP with GTP.

Merlin inactivation of Src signaling was also shown in CNS glial cells, where merlin competitively inhibits Src binding to ErbB2 thereby preventing ErbB2-mediated Src phosphorylation and downstream mitogenic signaling.

Merlin inactivation of Src signaling was also shown in CNS glial cells, where merlin competitively inhibits Src binding to ErbB2 thereby preventing ErbB2 mediated Src phosphorylation and downstream mitogenic signaling.

Merlin interacts with tubulin and acetylated-tubulin and stabilizes the microtubules by attenuating tubulin turnover -- lowering the rates of microtubule polymerization and depolymerization.

Merlin interacts with tubulin and acetylated-tubulin and stabilizes the microtubules by attenuating tubulin turnover—lowering the rates of microtubule polymerization and depolymerization.

Merlin inhibits PI3K activity by binding phosphatidylinositol 3-kinase enhancer-L (PIKE-L), the GTPase that binds and activates PI3K.

HDAC inhibitors disrupt the PP1-HDAC interaction facilitating Akt dephosphorylation and decrease human meningioma and schwannoma cell proliferation and schwannoma growth in an allograft model and meningioma growth in an intracranial xenograft model ( xref , xref , xref ).

Hyaluronan-CD44 interaction in astrocytes and an immortalized mouse mammary epithelial cell line, EpH4, leads to Rac1 signaling activation and actin cytoskeleton rearrangement ( xref , xref ).

In various cell types, the binding of hyaluronan to CD44 stimulates Tiam1 dependent Rac1 signaling and cytoskeleton mediated tumor cell migration.

In various cell types, the binding of hyaluronan to CD44 stimulates Tiam1 dependent Rac1 signaling and cytoskeleton mediated tumor cell migration.

Pharmacological or genetic inhibition of Rac1 in Nf2 -/- MEFs reduced the Wnt signaling activation to basal levels as assessed by reporter assay of transactivation of the nuclear beta-catenin-dependent T-cell factor 4 transcription factor.

In sub-confluent primary Schwann cells, we found that merlin binds to paxillin and mediates merlin localization at the plasma membrane and association with beta1-integrin and ErbB2, modifying the organization of the actin cytoskeleton in a cell density dependent manner.

In sub-confluent primary Schwann cells, we found that merlin binds to paxillin and mediates merlin localization at the plasma membrane and association with beta1-integrin and ErbB2, modifying the organization of the actin cytoskeleton in a cell density dependent manner.

FAK silencing decreased schwannoma cell proliferation and was associated with increased levels of total and nuclear p53.

In a similar fashion, NF2 mutations increased the resistance to dihydrofolate reductase inhibitors methotrexalate and pyremethamine as well as the JNK inhibitor JNK-9L.

Furthermore, it was shown that overactive PAK and LIMK pathway activity contributed to cell proliferation through cofilin phosphorylation and auroraA activation.

Interestingly, it was shown that schwannoma cells release insulin like growth factor binding protein 1 which in beta1-integrin dependent manner activates Src and FAK signaling.

Interestingly, it was shown that schwannoma cells release insulin like growth factor binding protein 1 which in beta1-integrin dependent manner activates Src and FAK signaling.

Moreover, neuregulin survival signaling through the ErbB2 and ErbB3 receptor activates PI3K in rat Schwann cells through the activation of Akt and inhibition of Bad, a pro apoptotic Blc-2 family protein.

ErbB2 activation in mouse Nf2 deficient spinal cord neural progenitor cells was shown to be caused by Rac mediated retention of the receptor at the plasma membrane.

Silencing DCAF1 in Meso-33, merlin deficient mesothelioma cells reduced their proliferation by arresting the cell cycle in G1 phase.

Significantly, silencing of DCAF1 in schwannoma cells isolated from NF2 patients also reduced their proliferation.

Silencing DCAF1 in Meso-33, merlin deficient mesothelioma cells reduced their proliferation by arresting the cell cycle in G1 phase.

Furthermore, Amot silencing attenuated Rac1 and Ras and MAPK signaling pathway.

Silencing of Amot in Nf2 -/- Schwann cells (SC4) selectively reduced cell proliferation because it did not change the proliferation rate of SC4 with merlin re-expression.

Furthermore, Amot silencing attenuated Rac1 and Ras and MAPK signaling pathway.

Furthermore, Amot silencing attenuated Rac1 and Ras and MAPK signaling pathway.

In various cell types, the binding of hyaluronan to CD44 stimulates Tiam1 dependent Rac1 signaling and cytoskeleton mediated tumor cell migration.

In various cell types, the binding of hyaluronan to CD44 stimulates Tiam1 dependent Rac1 signaling and cytoskeleton mediated tumor cell migration.

First, protein kinase C potentiated phosphatase inhibitor (CPI-17), which is frequently overexpressed in mesothelioma tumors, inhibits merlin phosphatase MYPT1-PP1delta, providing one potential pathway by which merlin 's tumor suppressor function might be inactivated through maintenance of phosphorylation at Ser518.

First, protein kinase C potentiated phosphatase inhibitor (CPI-17), which is frequently overexpressed in mesothelioma tumors, inhibits merlin phosphatase MYPT1-PP1delta, providing one potential pathway by which merlin 's tumor suppressor function might be inactivated through maintenance of phosphorylation at Ser518.

In various cell types, the binding of hyaluronan to CD44 stimulates Tiam1 dependent Rac1 signaling and cytoskeleton mediated tumor cell migration.

Finally, a recent meningioma study of 73 patients found a high incidence of TERT promoter activating mutations in meningiomas undergoing malignant transformation in both NF2-related and sporadic meningiomas, whereas no TERT mutations were found in benign tumors.

We recently showed that PI3K inhibition in merlin deficient mouse Schwann cells selectively decreased their proliferation.

In primary rat Schwann cells, CD44 was shown to constitutively associate with the heterodimer receptor tyrosine kinase ErbB2 and ErbB3 and CD44 enhanced neuregulin induced ErbB2 activating phosphorylation.

Moreover, neuregulin survival signaling through the ErbB2 and ErbB3 receptor activates PI3K in rat Schwann cells through the activation of Akt and inhibition of Bad, a pro apoptotic Blc-2 family protein.

In the canonical hippo pathway, mammalian Ste20 like kinases (Mst1/2; hippo homolog) phosphorylate large tumor suppressor kinases (LATS 1/2), which in turn phosphorylate and inactivate YAP and TAZ, blocking their role as TEAD and MEAD transcription factor co-activators.

SOS is a GEF that activates Ras by catalyzing the nucleotide exchange.

The data suggest that in hepatocytes merlin is functionally linked to the hippo pathway and acts upstream Mst1/2 by recruiting LATS to the membrane comparable to what has been shown in FH912 Schwann cell line.

Translocation of merlin to the nucleus allows merlin to bind and inhibit the E3 ubiquitin ligase CRL4 DCAF1 ( D DB1- and C ul4- A ssociated F actor 1) ( xref , xref ).

Translocation of merlin to the nucleus allows merlin to bind and inhibit the E3 ubiquitin ligase CRL4 DCAF1 (DDB1- and Cul4 Associated Factor 1).

For example, in confluent human umbilical vein endothelial cells, merlin suppressed recruitment of Rac to the plasma membrane, and its silencing promoted recruitment of Rac1 to sites of extracellular matrix adhesion, and promoted cell growth ( xref ).

Previously, we showed that activation of ErbB2/ErbB3 receptors in primary rat Schwann cells by neuregulin-1 induced merlin phosphorylation at Ser518 via PKA ( xref ).

Notably, NF2 transfection into these cells induced YAP1 phosphorylation at Ser127, YAP1 retention in the cytoplasm and consequent reduction of YAP1 nuclear localization.

Previously, we showed that activation of ErbB2 and ErbB3 receptors in primary rat Schwann cells by neuregulin-1 induced merlin phosphorylation at Ser518 via PKA.

Previously, we showed that activation of ErbB2 and ErbB3 receptors in primary rat Schwann cells by neuregulin-1 induced merlin phosphorylation at Ser518 via PKA.

Previously, we showed that activation of ErbB2 and ErbB3 receptors in primary rat Schwann cells by neuregulin-1 induced merlin phosphorylation at Ser518 via PKA.

We reported that merlin associates with beta 1 -integrin in primary Schwann cells and undifferentiated Schwann cell and neuron co-cultures, and in primary Schwann cell cultures, laminin-1 stimulated integrin signaled though PAK1 and caused merlin Ser518 phosphorylation and inactivation of its tumor suppressor function.

Merlin is phosphorylated at Ser10, Thr230 and Ser315 by Akt (also known as protein kinase B, PKB) and controls merlin’s proteasome-mediated degradation by ubiquitination to prevent its interaction with binding partners ( xref , xref ).

Merlin is phosphorylated at Ser10, Thr230 and Ser315 by Akt (also known as protein kinase B, PKB) and controls merlin 's proteasome mediated degradation by ubiquitination to prevent its interaction with binding partners.

Merlin is phosphorylated at Ser10, Thr230 and Ser315 by Akt (also known as protein kinase B, PKB) and controls merlin 's proteasome mediated degradation by ubiquitination to prevent its interaction with binding partners.

Merlin is phosphorylated at Ser10, Thr230 and Ser315 by Akt (also known as protein kinase B, PKB) and controls merlin’s proteasome-mediated degradation by ubiquitination to prevent its interaction with binding partners ( xref , xref ).

Merlin is phosphorylated at Ser10, Thr230 and Ser315 by Akt (also known as protein kinase B, PKB) and controls merlin’s proteasome-mediated degradation by ubiquitination to prevent its interaction with binding partners ( xref , xref ).

Merlin is phosphorylated at Ser10, Thr230 and Ser315 by Akt (also known as protein kinase B, PKB) and controls merlin 's proteasome mediated degradation by ubiquitination to prevent its interaction with binding partners.

Loss of merlin results in integrin mediated activation of mTORC1 through PAK1, which promotes cell cycle progression by inducing translation of cyclin-D1 mRNA and cyclin-D1 expression.

Loss of merlin in mesotheliomas has been linked not only to increased proliferation, but also increased invasiveness, spreading and migration.

Adenoviral transduction of NF2 in Meso-17 and Meso-25 cell lines decreased invasion through Matrigel membranes compared to cells transduced with empty vector.

Second, similar to NF2 schwannomas, mesothelioma cells with NF2 inactivation, exhibit activated PAK1 and AKT, and re-expression of merlin in merlin-null human mesothelioma cells (Meso-17) decreases PAK1 activity.

Soon after merlin was cloned, evidence that merlin inhibits another important member of the Rho GTPases family, Ras, was reported in v-Ha-Ras-transformed NIH3T3cells in which merlin overexpression counteracted the oncogenic role of Ras.

Merlin re-expression in Nf2 -/- Schwann cells similarly reduced the transport of growth factor receptors ErbB2 and ErbB3, insulin like growth factor 1 receptor (IGF1R) and platelet derived growth factor receptor (PDGFR).

Merlin re-expression in Nf2 -/- Schwann cells similarly reduced the transport of growth factor receptors ErbB2 and ErbB3, insulin like growth factor 1 receptor (IGF1R) and platelet derived growth factor receptor (PDGFR).

In sum, multiple lines of evidence have established a feedback regulation loop with merlin being phosphorylated at Ser518 (growth permissive form) via activated Rho small GTPases Rac1 and Cdc42 through PAK, and in turn, merlin associating with PAK to inhibit Rac1 and Cdc42 signaling (XREF_FIG).

Collectively, these results indicate that merlin inhibits cell growth by contact inhibition in part by binding CD44 and negatively regulating CD44 function (XREF_FIG).

Merlin inactivation of Src signaling was also shown in CNS glial cells, where merlin competitively inhibits Src binding to ErbB2 thereby preventing ErbB2 mediated Src phosphorylation and downstream mitogenic signaling.

In the NF2 -/- breast cancer MDA-MB-231 cell line, merlin re-expression inhibited YAP and TEAD activity that was eliminated by LATS1/2 silencing.

Loss of merlin results in integrin mediated activation of mTORC1 through PAK1, which promotes cell cycle progression by inducing translation of cyclin-D1 mRNA and cyclin-D1 expression.

Loss of merlin activated mTORC1 signaling independently of Akt or ERK in these tumor cells; however, the molecular mechanism connecting merlin loss to mTORC1 activation remains to be elucidated.

Loss of merlin activated mTORC1 signaling independently of Akt or ERK in these tumor cells; however, the molecular mechanism connecting merlin loss to mTORC1 activation remains to be elucidated.

Furthermore, merlin overexpression in Tr6BC1 mouse schwannoma cells inhibited the binding of fluorescein labeled hyaluronan to CD44 and inhibited subcutaneous tumor growth in immunocompromised mice, and overexpression of a merlin mutant lacking the CD44 binding domain was unable to inhibit schwannoma growth.

Further studies showed that wild-type merlin is transported throughout the cell by microtubule motors and merlin mutants or depletion of the microtubule motor kinesin-1 suppressed merlin transport and was associated with accumulation of yorkie, a Drosophila homolog of the hippo pathway transcriptional co-activator Yes associated protein (YAP), in the nucleus.

In a similar fashion, NF2 mutations increased the resistance to dihydrofolate reductase inhibitors methotrexalate and pyremethamine as well as the JNK inhibitor JNK-9L.

The disrupted cell-contact inhibition signaling and merlin phosphorylation correlated with increased expression of NOTCH1 and its downstream target gene, HES1, which represses the transcription factor E2F in cell-contact growth arrest.

Binding of merlin unphosphorylated at Ser518 with the cytoplasmic tail of CD44 mediates contact inhibition at high cell density.

Loss of merlin activated mTORC1 signaling independently of Akt or ERK in these tumor cells; however, the molecular mechanism connecting merlin loss to mTORC1 activation remains to be elucidated.

First, protein kinase C potentiated phosphatase inhibitor (CPI-17), which is frequently overexpressed in mesothelioma tumors, inhibits merlin phosphatase MYPT1-PP1delta, providing one potential pathway by which merlin 's tumor suppressor function might be inactivated through maintenance of phosphorylation at Ser518.

First, protein kinase C potentiated phosphatase inhibitor (CPI-17), which is frequently overexpressed in mesothelioma tumors, inhibits merlin phosphatase MYPT1-PP1delta, providing one potential pathway by which merlin 's tumor suppressor function might be inactivated through maintenance of phosphorylation at Ser518.

Loss of merlin results in integrin mediated activation of mTORC1 through PAK1, which promotes cell cycle progression by inducing translation of cyclin-D1 mRNA and cyclin-D1 expression.

HDAC inhibitors disrupt the PP1-HDAC interaction facilitating Akt dephosphorylation and decrease human meningioma and schwannoma cell proliferation and schwannoma growth in an allograft model and meningioma growth in an intracranial xenograft model.

The mTORC1 inhibitor rapamycin selectively inhibited proliferation of seven merlin-null mesothelioma cell lines, but not merlin positive cell lines, suggesting a potential pharmacological target for merlin deficient mesotheliomas.

Merlin expression in Meso-17 and Meso-25 cells decreased FAK Tyr397 phosphorylation and consequently disrupted FAK-Src and PI3K interaction, providing a mechanism for the observed enhancement of invasion and spreading caused by merlin inactivation.

Accordingly, merlin was shown to reduce the levels of ErbB2 and ErbB3 receptor levels at the plasma membrane.

Accordingly, merlin was shown to reduce the levels of ErbB2 and ErbB3 receptor levels at the plasma membrane.

Accordingly, merlin was shown to reduce the levels of ErbB2 and ErbB3 receptor levels at the plasma membrane.

In sub-confluent primary Schwann cells, we found that merlin binds to paxillin and mediates merlin localization at the plasma membrane and association with beta1-integrin and ErbB2, modifying the organization of the actin cytoskeleton in a cell density dependent manner.

In sub-confluent primary Schwann cells, we found that merlin binds to paxillin and mediates merlin localization at the plasma membrane and association with β1-integrin and ErbB2, modifying the organization of the actin cytoskeleton in a cell density-dependent manner ( xref ).

Moreover, in cultured Schwann cells, merlin interaction with Amot was demonstrated by co-immunoprecipitation of the endogenous proteins.

Moreover, in cultured Schwann cells, merlin interaction with Amot was demonstrated by co-immunoprecipitation of the endogenous proteins ( xref ).

Merlin-Amot interaction was required for merlin regulation of mitogenic MAPK signaling.

Moreover, co-immunoprecipitation experiments revealed that merlin interacts with YAP1, although the interaction is not direct.

Moreover, co-immunoprecipitation experiments revealed that merlin interacts with YAP1, although the interaction is not direct ( xref ).

Studies in human meningioma tumors and in paired cell lines—KY21MG1 or MENII-1 meningioma cell lines and AC1 arachnoidal cells—demonstrated that merlin loss was associated with increased YAP expression and nuclear localization.

Amot-p130 isoform bound to the WW domains of YAP and blocked LATS1 access to YAP.

The activation of Rac1 through CD44 was identified via the interaction of CD44 with Tiam-1, a Rac1 guanine nucleotide exchange factor (GEF) that catalyzes the replacement of the tightly-bound GDP with GTP.

Merlin inactivation of Src signaling was also shown in CNS glial cells, where merlin competitively inhibits Src binding to ErbB2 thereby preventing ErbB2-mediated Src phosphorylation and downstream mitogenic signaling.

Merlin inactivation of Src signaling was also shown in CNS glial cells, where merlin competitively inhibits Src binding to ErbB2 thereby preventing ErbB2 mediated Src phosphorylation and downstream mitogenic signaling.

Merlin interacts with tubulin and acetylated-tubulin and stabilizes the microtubules by attenuating tubulin turnover -- lowering the rates of microtubule polymerization and depolymerization.

Merlin interacts with tubulin and acetylated-tubulin and stabilizes the microtubules by attenuating tubulin turnover—lowering the rates of microtubule polymerization and depolymerization.

Merlin inhibits PI3K activity by binding phosphatidylinositol 3-kinase enhancer-L (PIKE-L), the GTPase that binds and activates PI3K.

HDAC inhibitors disrupt the PP1-HDAC interaction facilitating Akt dephosphorylation and decrease human meningioma and schwannoma cell proliferation and schwannoma growth in an allograft model and meningioma growth in an intracranial xenograft model ( xref , xref , xref ).

Hyaluronan-CD44 interaction in astrocytes and an immortalized mouse mammary epithelial cell line, EpH4, leads to Rac1 signaling activation and actin cytoskeleton rearrangement ( xref , xref ).

In various cell types, the binding of hyaluronan to CD44 stimulates Tiam1 dependent Rac1 signaling and cytoskeleton mediated tumor cell migration.

In various cell types, the binding of hyaluronan to CD44 stimulates Tiam1 dependent Rac1 signaling and cytoskeleton mediated tumor cell migration.

Pharmacological or genetic inhibition of Rac1 in Nf2 -/- MEFs reduced the Wnt signaling activation to basal levels as assessed by reporter assay of transactivation of the nuclear beta-catenin-dependent T-cell factor 4 transcription factor.

In sub-confluent primary Schwann cells, we found that merlin binds to paxillin and mediates merlin localization at the plasma membrane and association with beta1-integrin and ErbB2, modifying the organization of the actin cytoskeleton in a cell density dependent manner.

In sub-confluent primary Schwann cells, we found that merlin binds to paxillin and mediates merlin localization at the plasma membrane and association with beta1-integrin and ErbB2, modifying the organization of the actin cytoskeleton in a cell density dependent manner.

FAK silencing decreased schwannoma cell proliferation and was associated with increased levels of total and nuclear p53.

In a similar fashion, NF2 mutations increased the resistance to dihydrofolate reductase inhibitors methotrexalate and pyremethamine as well as the JNK inhibitor JNK-9L.

Furthermore, it was shown that overactive PAK and LIMK pathway activity contributed to cell proliferation through cofilin phosphorylation and auroraA activation.

Interestingly, it was shown that schwannoma cells release insulin like growth factor binding protein 1 which in beta1-integrin dependent manner activates Src and FAK signaling.

Interestingly, it was shown that schwannoma cells release insulin like growth factor binding protein 1 which in beta1-integrin dependent manner activates Src and FAK signaling.

Moreover, neuregulin survival signaling through the ErbB2 and ErbB3 receptor activates PI3K in rat Schwann cells through the activation of Akt and inhibition of Bad, a pro apoptotic Blc-2 family protein.

ErbB2 activation in mouse Nf2 deficient spinal cord neural progenitor cells was shown to be caused by Rac mediated retention of the receptor at the plasma membrane.

Silencing DCAF1 in Meso-33, merlin deficient mesothelioma cells reduced their proliferation by arresting the cell cycle in G1 phase.

Significantly, silencing of DCAF1 in schwannoma cells isolated from NF2 patients also reduced their proliferation.

Silencing DCAF1 in Meso-33, merlin deficient mesothelioma cells reduced their proliferation by arresting the cell cycle in G1 phase.

Furthermore, Amot silencing attenuated Rac1 and Ras and MAPK signaling pathway.

Silencing of Amot in Nf2 -/- Schwann cells (SC4) selectively reduced cell proliferation because it did not change the proliferation rate of SC4 with merlin re-expression.

Furthermore, Amot silencing attenuated Rac1 and Ras and MAPK signaling pathway.

Furthermore, Amot silencing attenuated Rac1 and Ras and MAPK signaling pathway.