RING finger, H2 subclass, found in Saccharomyces cerevisiae vacuolar membrane protein PEP3 (Pep3p) and similar proteins
Pep3p, also known as carboxypeptidase Y-deficient protein 3, vacuolar morphogenesis protein 8, vacuolar protein sorting-associated protein 18 (Vps18p), or vacuolar protein-targeting protein 18, is a vacuolar membrane protein that affects late Golgi functions required for vacuolar protein sorting and efficient alpha-factor prohormone maturation. It is required for vacuolar biogenesis caused hypersensitivity to heat shock and ethanol stresses, probably due to disappearance of normal vacuoles. As a component of the homotypic fusion and vacuole protein sorting (HOPS) and class C core vacuole/endosome tethering (CORVET) complexes, its overexpression shortens lag phase but does not alter growth rate in Saccharomyces cerevisiae exposed to acetic acid stress. Moreover, Pep3p forms the Class C Vps protein complex (C-Vps complex) with Pep5p (also known as Vps11), Vps16, and Vps33, and is necessary for trafficking of hydrolase precursors to the vacuole by promoting vesicular docking reactions with SNARE proteins. Pep3p contains a C3H2C3-type RING-H2 finger at the C-terminus.