This gene encodes a member of the adhesion-GPCR receptor family  expressed predominantly by cells of the immune system. Family members are characterized by an extended extracellular region with a variable number of N-terminal protein modules coupled to a TM7 region via a domain known as the GPCR-Autoproteolysis INducing (GAIN) domain. In the case of CD97 the N-terminal domains consist of alternatively spliced epidermal growth factor (EGF)-like domains. These mediate binding to its cellular ligand, decay accelerating factor (DAF/CD55), a regulatory protein of the complement cascade, however the CD55-CD97 interaction is believed to have an activity independent of complement. Alternative splicing has been observed for this gene and three variants have been found.
CD97 is an adhesion GPCR that is normally found on tissue of hematapoetic origin and in smooth muscle. It signals through Gα12/13 and activates RHO. It has been found to be upregulated in Cancers, including prostate, breast, and thyroid. In prostate cancer. it has been shown that CD97 is hetoerodimerizing with another GPCR, LPAR. The interaction is believed to further enhance the RHO signaling between both receptors.
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