Recombinant Human Melanoma gp100 protein (GST tag N-Terminus)

Specifications

Form

Liquid

General info

Function

Forms physiological amyloids that play a central role in melanosome morphogenesis and pigmentation. The maturation of unpigmented premelanosomes from stage I to II is marked by assembly of processed amyloidogenic fragments into parallel fibrillar sheets, which elongate the vesicle into a striated ellipsoidal shape. In pigmented stage III and IV melanosomes, the amyloid matrix serves as a platform where eumelanin precursors accumulate at high local concentrations for pigment formation. May prevent pigmentation-associated toxicity by sequestering toxic reaction intermediates of eumelanin biosynthesis pathway.. Represents a potent melanoma-specific antigen. Among melanoma non-mutated self-peptides, G9-154 (KTWGQYWQV), G9-209 (ITDQVPFSV) and G9-280 (YLEPGPVTA), appear to act as immunodominant common epitopes that stimulate anti-tumor immune response mediated by HLA-A-restricted cytotoxic T cells.

Sequence similarities

Belongs to the PMEL/NMB family.

Post-translational modifications

N- and O-glycosylated. A small amount of P1/P100 (major form) undergoes glycosylation in ER and Golgi compartments to yield P2/P120 (minor form). The mature P2 form leaves the trans-Golgi network and is mainly targeted to stage I melanosomes via the plasma membrane and clathrin-mediated endocytosis. Stage II melanosomes harbor only Golgi-modified fragments that are derived from M-alpha and that bear sialylated O-linked oligosaccharides. O-glycosylation of the RPT region is a conserved feature likely involved in amyloid sheet separation via electrostatic repulsion.. Undergoes multiple proteolytic processing. In a post-Golgi prelysosomal compartment, P2 is cleaved by a furin-like proprotein convertase (PC) into two disulfide-linked subunits: a large lumenal subunit, M-alpha/ME20-S, and an integral membrane subunit, M-beta. Despite cleavage, only a small fraction of M-alpha is secreted, as most M-alpha and M-beta remain associated with each other intracellularly via a disulfide bond (PubMed:11694580, PubMed:12732614, PubMed:15096515, PubMed:15695812, PubMed:17991747). Once targeted to stage I melanosomes, beta-secretase BACE2 cleaves the M-beta fragment to release the amyloidogenic luminal fragment containing M-alpha and a small portion of M-beta N-terminus (PubMed:23754390). M-alpha is further cleaved by metalloproteinases, likely ADAM10 or ADAM17, and still unknown proteases to yield subfragments that ultimately assemble into amyloid fibrils (PubMed:19047044). The C-terminal fragment of M-beta is processed by the gamma-secretase complex to release a short intracytoplasmic domain (PubMed:19047044).