CD81 antigen; 26 kD cell surface protein TAPA-1; target of the antiproliferative antibody 1; tetraspanin-28; Tspan-28 (CD81, TAPA1, TSPAN28)

Function

• component of CD19/CD21/Leu-13 signal transduction complex
• role in regulation of cell growth
• interacts directly with IGSF8

Structure

• not glycosylated (probable)
• belongs to the tetraspanin (TM4SF) family

Compartment

membrane

Expression

• lymphocytes
• endothelial cells
• epithelial cells
• negative antibody staining in:
  • erythrocytes
  • platelets
  • neutrophils

Pathology

• may act as a viral receptor for hepatitis C virus (HCV); role in HCV attachment &/or cell entry by interacting with HCV E1/E2 glycoproteins heterodimer
• role in the regulation of lymphoma cell growth
• expressed in hematolymphoid, neuroectodermal & mesenchymal tumor cell lines

More general terms

• tetraspanin (transmembrane-4-superprotein)
• CD antigen

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=975
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:975
• OMIM: https://mirror.omim.org/entry/186845
• UniProt: http://www.uniprot.org/uniprot/P60033.html