This gene encodes a scaffold protein that functions in the extracellular signal-regulated kinase (ERK) cascade. The protein is localized to late endosomes by the mitogen-activated protein-binding protein-interacting protein, and binds specifically to MAP kinase kinase MAP2K1/MEK1, MAP kinase MAPK3/ERK1, and MAP kinase MAPK1/ERK2. Studies of the orthologous gene in mouse indicate that it regulates late endosomal traffic and cell proliferation. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. A pseudogene of this gene is located on the long arm of chromosome 13. Alias Symbols: MAP2K1IP1, MAPBP, MAPKSP1, MP1, PRO0633, Ragulator3 Protein Interaction Partner: NIF3L1, LAMTOR2, IBTK, MBD2, BHMT, PEF1, C19orf70, MRPL43, PRR3, LPCAT1, MRPS9, MRPS35, MRPL47, TOMM22, DDX28, TSR1, RNMTL1, LAMTOR1, NDUFB11, TMCO1, MRPL39, PTRH2, RAB14, MRPL51, MRPL22, UQCRQ, PUF60, RAB31, TOMM40, MSLN, TOMM70A, NUPL1, SPCS2, PICALM, V Protein Size: 124