VPS15
VPS15, encoded by PIK3R4 and commonly called p150, is the regulatory subunit of the class III phosphoinositide 3-kinase complex. It is N-terminally myristoylated and binds the lipid kinase VPS34/PIK3C3 together with Beclin-1 (BECN1) and either ATG14 or UVRAG, stimulating VPS34 to produce PI3P for autophagosome formation and endosomal sorting. Although VPS15 contains a protein kinase-like domain with substitutions in key catalytic motifs, most evidence indicates it functions primarily as a scaffold and activator rather than as an active Ser/Thr kinase. It is essential in mouse development, and recombinant VPS15 is used to reconstitute PI3P-producing complexes for autophagy and trafficking assays.
