On 2014 Aug 07, Randy Blakely commented:

In this paper, the authors report an inability of an hDAT E602G mutant to transport DA or to reach the cell surface. The findings are at odds with a study from my lab (Expression studies of naturally occurring human dopamine transporter variants identifies a novel state of transporter inactivation associated with Val382Ala. Mazei-Robison MS, Blakely RD. Neuropharmacology. 2005 Nov;49(6):737-49). Although the impact of the E602G mutation warrants further analysis, discussions with Drs. Horschitz and Schloss lead to retraction of the Horschitz et al paper As the authors note in their retraction (S Horschitz, R Hummerich, T Lau, M Rietschel & P Schloss Molecular Psychiatry 11, 704-704, 27 June 2006):

"Mazei-Robison and Blakely have published in Neuropharmacology (2005) 49, 737–749, a characterization of several naturally occurring mutants of hDAT. In contrast to our data, in their study the E602G mutant was fully active and comparable to wild-type hDAT. In order to elucidate these contradictory results, both our labs exchanged the mutant cDNAs and re-analysed the properties of the E602G mutant. Uptake experiments in both labs with HEK 293 transiently transfected with both cDNA plasmids revealed transport activity of the E602G mutant comparable to wild-type hDAT. Thus, our conclusion published in Molecular Psychiatry (2005) 10, 1104–1109 is wrong and has to be withdrawn at this point of time."

Since the original Horschitz et al report continues to be cited inappropriately as support for a role for altered DAT (or DA signaling) in BPD, I am hoping the PubMed Commons forum will provide a suitable opportunity to redirect readers attention to the, as yet, unknown properties of the E602G mutation that may include alterations in roles of the hDAT C-terminus (membrane trafficking, interactions with regulatory proteins, DA efflux, e.g. Calmodulin kinase II interacts with the dopamine transporter C terminus to regulate amphetamine-induced reverse transport. Fog JU, Khoshbouei H, Holy M, Owens WA, Vaegter CB, Sen N, Nikandrova Y, Bowton E, McMahon DG, Colbran RJ, Daws LC, Sitte HH, Javitch JA, Galli A, Gether U. Neuron. 2006 Aug 17;51(4):417-29; Attention deficit/hyperactivity disorder-derived coding variation in the dopamine transporter disrupts microdomain targeting and trafficking regulation. Sakrikar D, Mazei-Robison MS, Mergy MA, Richtand NW, Han Q, Hamilton PJ, Bowton E, Galli A, Veenstra-Vanderweele J, Gill M, Blakely RD. J Neurosci. 2012 Apr 18;32(16):5385-97. doi: 10.1523/JNEUROSCI.6033-11.2012. Erratum in: J Neurosci. 2012 Oct 31;32(44):15643).

On 2014 Aug 07, Randy Blakely commented:

In this paper, the authors report an inability of an hDAT E602G mutant to transport DA or to reach the cell surface. The findings are at odds with a study from my lab (Expression studies of naturally occurring human dopamine transporter variants identifies a novel state of transporter inactivation associated with Val382Ala. Mazei-Robison MS, Blakely RD. Neuropharmacology. 2005 Nov;49(6):737-49). Although the impact of the E602G mutation warrants further analysis, discussions with Drs. Horschitz and Schloss lead to retraction of the Horschitz et al paper As the authors note in their retraction (S Horschitz, R Hummerich, T Lau, M Rietschel & P Schloss Molecular Psychiatry 11, 704-704, 27 June 2006):

"Mazei-Robison and Blakely have published in Neuropharmacology (2005) 49, 737–749, a characterization of several naturally occurring mutants of hDAT. In contrast to our data, in their study the E602G mutant was fully active and comparable to wild-type hDAT. In order to elucidate these contradictory results, both our labs exchanged the mutant cDNAs and re-analysed the properties of the E602G mutant. Uptake experiments in both labs with HEK 293 transiently transfected with both cDNA plasmids revealed transport activity of the E602G mutant comparable to wild-type hDAT. Thus, our conclusion published in Molecular Psychiatry (2005) 10, 1104–1109 is wrong and has to be withdrawn at this point of time."

Since the original Horschitz et al report continues to be cited inappropriately as support for a role for altered DAT (or DA signaling) in BPD, I am hoping the PubMed Commons forum will provide a suitable opportunity to redirect readers attention to the, as yet, unknown properties of the E602G mutation that may include alterations in roles of the hDAT C-terminus (membrane trafficking, interactions with regulatory proteins, DA efflux, e.g. Calmodulin kinase II interacts with the dopamine transporter C terminus to regulate amphetamine-induced reverse transport. Fog JU, Khoshbouei H, Holy M, Owens WA, Vaegter CB, Sen N, Nikandrova Y, Bowton E, McMahon DG, Colbran RJ, Daws LC, Sitte HH, Javitch JA, Galli A, Gether U. Neuron. 2006 Aug 17;51(4):417-29; Attention deficit/hyperactivity disorder-derived coding variation in the dopamine transporter disrupts microdomain targeting and trafficking regulation. Sakrikar D, Mazei-Robison MS, Mergy MA, Richtand NW, Han Q, Hamilton PJ, Bowton E, Galli A, Veenstra-Vanderweele J, Gill M, Blakely RD. J Neurosci. 2012 Apr 18;32(16):5385-97. doi: 10.1523/JNEUROSCI.6033-11.2012. Erratum in: J Neurosci. 2012 Oct 31;32(44):15643).