Identification of NSF as a novel binding partner of SERT. (A) GST-N-SERT and GST-C-SERT were incubated with and without (as negative controls) the mouse brain extract. Bound proteins were detected by SDS-PAGE and silver staining. At least ten and three specific bands were observed in the GST-N-SERT and GST-C-SERT lanes, respectively, compared with negative controls. (B) Analysis using Mascot identified 24 peptides (in red) that matched NSF from band N-4 (in red on (A)). (C) N-tail-specific binding of NSF to SERT was confirmed by Western blot analysis. C-SERT, C-terminal domain of the serotonin transporter; GST, glutathione S-transferase; GST-C, GST-C-SERT; GST-N, GST-N-SERT; N-SERT, N-terminal domain of the serotonin transporter; NSF, N-ethylmaleimide-sensitive factor; MW, molecular weight.