Vacuolar protein sorting-associated protein 33A (Vps33a)

Plays a role in vesicle-mediated protein trafficking to lysosomal compartments including the endocytic membrane transport and autophagic pathways. Believed to function as a core component of the putative HOPS and CORVET endosomal tethering complexes that are proposed to participate in the Rab5-to-Rab7 endosome conversion likely implicating MON1A/B, and through binding SNAREs and SNARE complexes to mediate tethering and docking events during SNARE-mediated membrane fusion.

The HOPS complex is proposed to be recruited to Rab7 on the late endosomal membrane and to modulate late endocytic, phagocytic and autophagic traffic towards lysosomes. The CORVET complex is proposed to function as a Rab5 effector to mediate early endosome fusion likely in particular endosome subpopulations.