Sec10

Sec10 is a conserved component of the exocyst complex, a multisubunit tethering assembly that plays a critical role in targeting and tethering secretory vesicles to the plasma membrane in eukaryotic cells. By coordinating vesicle docking with subsequent SNARE-mediated fusion, the exocyst supports polarized secretion and membrane growth in processes such as cell migration, growth, and development.

In most organisms, Sec10 is one of eight subunits that form the exocyst complex, alongside Sec3, Sec5, Sec6, Sec8, Sec15, Exo70, and Exo84. In mammals, Sec10 is encoded by the EXOC5 gene and shares functional conservation with its yeast ortholog Sec10p. The subunits interact to create a scaffold that anchors to the plasma membrane and binds secretory vesicles, with Sec10 contributing to the stability and assembly of the octameric complex. Sec10 also engages with other exocyst components, and through these interactions helps recruit the complex to sites of active exocytosis.

Localization of Sec10 to specific plasma membrane regions is guided by small GTPases of the Rab and Rho families, which regulate exocyst trafficking and assembly. Once tethered, the exocyst facilitates vesicle capture and alignment, enabling subsequent SNARE complex formation and vesicle fusion.

Biological relevance and research perspectives: Sec10 is essential for polarized secretion and proper cell polarity in various cell types, including yeast, epithelial, and neuronal cells. Disruption of exocyst function can lead to defects in secretion and polarity, and alterations in exocyst activity have been observed in several diseases and developmental contexts. Sec10 remains a focus of study for understanding the molecular mechanics of vesicle tethering and targeted exocytosis across species.