CD81 was originally identified as a Target of an Anti-Proliferative Antibody (TAPA-1) in a study that also defined a new family of transmembrane proteins, later named tetraspanins (Oren et al. 1990). CD81 is expressed on most human cell types; however, Oren et al. have shown that the sensitivity of diverse cell lineages to the anti-proliferative effect of the anti-CD81 antibody differed (Oren et al. 1990). Therefore, subsequent immune-co-precipitation studies were performed to reveal that CD81 associates with different partner proteins in the various cells types. For example, in B cells CD81 associates with CD19, a B cell specific signaling molecule. Similar studies on additional family members confirmed that tetraspanins tend to associate in the membrane with each other and with additional partner proteins. These tetraspanin-enriched microdomains (TEMs) are dynamic membrane entities, which act as signaling platforms (reviewed in (Levy...
- Coffey GP, Rajapaksa R, Liu R, Sharpe O, Kuo CC, Krauss SW, Sagi Y, Davis RE, Staudt LM, Sharman JP, Robinson WH, Levy S. Engagement of CD81 induces ezrin tyrosine phosphorylation and its cellular redistribution with filamentous actin. J Cell Sci. 2009;122:3137–44.PubMedPubMedCentralCrossRefGoogle Scholar