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 the ligand-mediated internalization and down-regulation of EGF receptor. 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 CD2AP and CIN85/SH3KBP1. Interacts with CD2AP (via one of the SH3 domains). Interacts with TSG101; the association appears to be mediated by the TSG101-VPS37 binary subcomplex. Interacts with VPS28. Interacts with VPS37B; the association appears to be mediated by the TSG101-VPS37 binary subcomplex. Interacts with VPS37C; the association appears to be mediated by the TSG101-VPS37 binary subcomplex. Interacts with VPS37D; the association appears to be mediated by the TSG101-VPS37 binary subcomplex. Interacts with CEP55. Colocalizes with F-actin. Some fraction may be nuclear. Ubiquitously expressed except in skeletal muscle. Phosphorylated on Tyr-204 upon EGF stimulation. Phosphorylation is required for interaction with CD2AP and CIN85/SH3KBP1. Does not interact with CD2AP. Belongs to the MVB12 family.