Component of the ESCRT-I complex, a regulator of vesicular trafficking process. Required for the sorting of endocytic ubiquitinated cargos into multivesicular bodies. May be involved in cell growth and differentiation (By similarity). Component of the ESCRT-I complex (endosomal sorting complex required for transport I) which consists of TSG101, VPS28, a VPS37 protein (VPS37A to -D) and MVB12A or MVB12B in a 1:1:1:1 stoichiometry. Interacts with TSG101, VPS28, MVB12A and MVB12B. Component of the ESCRT-I complex (endosomal sorting complex required for transport I) which consists of TSG101, VPS28, a VPS37 protein (VPS37A to -D) and UBAP1 in a 1:1:1:1 stoichiometry. Interacts with CEP55. Interacts with IST1 (By similarity). Recruited to the endosomal membrane in a VPS4A-dependent fashion. Belongs to the VPS37 family.