title: The septin CDCrel-1 binds syntaxin and inhibits exocytosis.
abstract: Septins are GTPases required for the completion of cytokinesis in diverse organisms, yet their roles in cytokinesis or other cellular processes remain unknown. Here we describe studies of a newly identified septin, CDCrel-1, which is predominantly expressed in the nervous system. This protein was associated with membrane fractions, and a significant fraction of the protein copurified and coprecipitated with synaptic vesicles. In detergent extracts, CDCrel-1 and another septin, Nedd5, immunoprecipitated with the SNARE protein syntaxin by directly binding to syntaxin via the SNARE interaction domain. Transfection of HIT-T15 cells with wild-type CDCrel-1 inhibited secretion, whereas GTPase dominant-negative mutants enhanced secretion. These data suggest that septins may regulate vesicle dynamics through interactions with syntaxin.
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000378:metabolism; D005089:Exocytosis / Q000502:physiology*; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D015723:Gene Library; D006801:Humans; D006825:Hybridomas; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D016716:PC12 Cells; D011485:Protein Binding; D050765:Qa-SNARE Proteins; D051381:Rats; D014162:Transfection