melanocyte protein Pmel 17; Silver locus protein homolog; melanocyte lineage-specific antigen GP100; melanoma-associated ME20 antigen; ME20-M; ME20M; contains: ME20-S; secreted melanoma-associated ME20 antigen; ME20S; 95 kD melanocyte-specific secreted glycoprotein (SILV, D12S53E, PMEL17)

Function

• may be a melanogenic enzyme
• may represent an oncofetal self-antigen that is normally expressed at low levels in quiescent adult melanocytes but overexpressed by proliferating neonatal melanocytes & during tumor growth
• release of the soluble form, ME20-S, could protect tumor cells from antibody mediated immunity

Structure

• belongs to the Pmel-17/NMB family
• contains 1 PKD domain

Compartment

• membrane; single-pass type 1 membrane protein (putative)
• melanosome, from stage 1 to stage 4
• ME20-S: secreted (probable); probably product of proteolytic cleavage

Expression

• preferentially expressed in melanomas
• some expression was found in dysplastic nevi
• not found in normal tissues nor in carcinomas

Laboratory

• Human Melanoma Black (HMB)-45 Ag in tissue

More general terms

• glycoprotein
• membrane protein

Database

• UniProt: http://www.uniprot.org/uniprot/P40967.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=6490
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:6490
• OMIM: https://mirror.omim.org/entry/155550