Sec23p:Sec24p Complex Sar1b:GDP Complex Sar1b:GTP:Sec23p:Sec24p Loss of Sar1b GTPase Authored: Gillespie, ME, 2007-07-13 20:42:29 EC Number: 3.6.5.1 EC Number: 3.6.5.2 EC Number: 3.6.5.3 EC Number: 3.6.5.4 Edited: Gillespie, ME, 2007-11-21 20:48:45 Pubmed10825291 Pubmed10982397 Pubmed17316621 Reactome Database ID Release 43203971 Reactome, http://www.reactome.org ReactomeREACT_12396 Reviewed: Gagneux, P, 2010-11-18 Sar1p-GTP hydrolysis is increased 15-30-fold by Sec23p. Sar1p-GDP is released as a result of this hydrolysis and used in further vesicle sculpting cycles. Sar1p-GTP hydrolysis occurs at two critical points during the cycle, first (as represented here) as a proofreading step, insuring that the cargo is loaded. Later in the cycle Sar1p-GTP hydrolysis triggers the uncoating of the budded vesicle.