Golgi Integral Membrane Protein 4 (GOLIM4)

The deduced 696-amino acid protein has a calculated molecular mass of about 82 kD, much smaller than the apparent mass of 130 kD derived from SDS-PAGE. GOLPH4 has a short N-terminal cytoplasmic tail with a protein kinase C phosphorylation site and a myristoylation site; a membrane-spanning segment; and a large C-terminal luminal domain with a potential N-glycosylation site, an O-glycosylation site, multiple phosphorylation sites, a putative leucine zipper, and a large number of heptad repeats predicted to participate in coiled-coil dimer formation.

Overexpression of GOLPH4 led to partial mislocation of the protein to endosomes rather than to the plasma membrane, suggesting that the protein contains Golgi-targeting information.