RING finger, H2 subclass, found in vacuolar protein sorting-associated protein 11 homolog (Vps11) and similar proteins
Vps11, also known as RING finger protein 108 (RNF108), is a soluble protein involved in regulation of glycolipid degradation and retrograde toxin transport. It is highly expressed in heart and pancreas. Vps11 associates with Vps16, Vps18, and Vps33 to form a Class C Vps core complex that is required for soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE)-mediated membrane fusion at the lysosome-like yeast vacuole. The core complex, together with two additional compartment-specific subunits, forms the tethering complexes HOPS (homotypic vacuole fusion and protein sorting) and CORVET (class C core vacuole/endosome transport) protein complexes. CORVET contains the additional Vps3 and Vps8 subunits. It operates at endosomes, controls traffic into late endosomes and interacts with the Rab5/Vps21-GTP form. HOPS contains the additional Vps39 and Vps41 subunits. It operates at the lysosomal vacuole, controls all traffic from late endosomes into the vacuole and interacts with the Rab7/Ypt7-GTP form. Vps11 is a central scaffold protein upon which both HOPS and CORVET assemble. The HOPS and CORVET complexes disassemble in the absent of Vps11, resulting in a massive fragmentation of vacuoles. Vps11 contains a clathrin repeat domain and a C-terminal C3H2C3-type RING-H2 finger. This subfamily also includes Vps11 homologs found in fungi, such as Saccharomyces cerevisiae vacuolar membrane protein Pep5p, also known as carboxypeptidase Y-deficient protein 5, vacuolar morphogenesis protein 1, or vacuolar biogenesis protein END1. Pep5p is essential for vacuolar biogenesis in Saccharomyces cerevisiae. It associates with Pep3p to form a core Pep3p/Pep5p complex that promotes vesicular docking/fusion reactions in conjunction with SNARE proteins at multiple steps in transport routes to the vacuole.