Sec15 is a component of the exocyst complex involved in the tethering of post-Golgi Golgi secretory vesicles to the plasma membrane during exocytosis and plays a role in several cellular functions such as cell polarisation, cytokinesis, ciliogenesis and tumour invasion [1,2]. The exocyst is one of the members of the complexes associated with tethering containing helical rods (CATCHR), together with COG, GARP, and Dsl1 complexes, which share a fold consisting of alpha-helical bundles forming a rod structure [2,3]. This is the C-terminal domain of Sec15 which mediates Rab GTPases binding in a GTP-dependent manner [4].

1: The Exocyst is a multiprotein complex required for exocytosis in Saccharomyces cerevisiae. TerBush DR, Maurice T, Roth D, Novick P; EMBO J 1996;15:6483-6494. PMID:8978675

2: Cryo-EM structure of the exocyst complex. Mei K, Li Y, Wang S, Shao G, Wang J, Ding Y, Luo G, Yue P, Liu JJ, Wang X, Dong MQ, Wang HW, Guo W; Nat Struct Mol Biol. 2018;25:139-146. PMID:29335562

3: Homology and Modular Evolution of CATCHR at the Origin of the Eukaryotic Endomembrane System. Santana-Molina C, Gutierrez F, Devos DP; Genome Biol Evol. 2021; [Epub ahead of print] PMID:34061181

4: Sec15 interacts with Rab11 via a novel domain and affects Rab11 localization in vivo. Wu S, Mehta SQ, Pichaud F, Bellen HJ, Quiocho FA; Nat Struct Mol Biol. 2005;12:879-885. PMID:16155582