Component of the ESCRT-I complex, a regulator of vesicular trafficking process. Required for normal endocytic and biosynthetic traffic to the yeast vacuole. Component of the ESCRT-I complex (endosomal sorting complex required for transport I) which consists of STP22, VPS28, SRN2 and MVB12 in a 1:1:1:1 stoichiometry. Interacts with STP22 and MVB12. Belongs to the VPS37 family.