CD9; p24; leukocyte antigen MIC3; Motility-related protein; MRP-1; tetraspanin-29; Tspan-29; 5H9 antigen; cell growth-inhibiting gene 2 protein (MIC3, TSPAN29, GIG2)

Function

• role in platelet activation & aggregation
• regulates paranodal junction formation
• required for gamete fusion
• involved in cell adhesion, cell motility
• forms both disulfide-linked homodimers & higher homooligomers as well as heterooligomers with other members of the tetraspanin family
• associates with CR2/CD21 & with PTGFRN/CD9P1
• interacts directly with IGSF8

Structure

• belongs to the tetraspanin (TM4SF) family
• protein exists in three forms with molecular masses between 22 & 27 kD, & is known to carry covalently linked fatty acids

Compartment

membrane

Expression

• expressed by a variety of hematopoietic & epithelial cells
• pre B cells
• subset of B cells
• T cells
• macrophages
• platelets
• eosinophils
• basophils
• megakaryocytes
• endothelial cells
• brain
• peripheral nerve
• vascular smooth muscle
• cardiac muscle
• epithelia

Pathology

• involved in tumor metastasis

More general terms

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

Database

• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:928
• OMIM: https://mirror.omim.org/entry/143030
• UniProt: http://www.uniprot.org/uniprot/P21926.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=928