CD97 (F1B5E) Rabbit Monoclonal Antibody #42684

CD97, also known as adhesion G protein-coupled receptor E5 (ADGRE5), is a prominent member of the adhesion G protein-coupled receptor (ADGRE) family, often referred to as the epidermal growth factor-7 transmembrane (EGF-TM7) family. This family is a unique class of receptors characterized by a large N-terminal extracellular region containing multiple tandem EGF-like domains, a mucin-like stalk, and a seven-transmembrane domain typical of GPCRs. CD97 is expressed as a heterodimer of a non-covalently bound α-subunit (extracellular) and β-subunit (transmembrane and intracellular), resulting from intracellular autocatalytic cleavage at a conserved GPCR proteolytic site (1,2).

CD97 exhibits the broadest expression pattern among EGF-TM7 family members, and is found on various cell types, including hematopoietic stem and progenitor cells, and other immune cells. It has been reported to play a role in leukocyte development, activation, and migration (3-5). It is also present on smooth muscle cells (e.g., vascular, skeletal, heart muscle cells), where it is thought to contribute to cell adhesion and muscle development (6). Through its EGF-like domains, CD97 can interact with various extracellular ligands, including CD55/DAF, chondroitin sulfate B, and selected integrins. These interactions mediate cell-cell and cell-matrix adhesion, and influence cell migration via activation of RhoA, Akt, and ERK signaling pathways (2,7,8). Upregulated CD97 is observed in a variety of human cancers, including gastric, colorectal, pancreatic, thyroid, and brain cancers, and its expression often correlates with advanced tumor stage, increased invasiveness, and poor patient prognosis. It has been shown that CD97 can enhance cancer cell migration, invasion, and metastasis, and promote angiogenesis by stimulating endothelial cell motility and invasion. Its soluble form can also act as a chemoattractant. In tumor cells, CD97 can activate pro-tumorigenic signaling via β-catenin, Akt, and RhoA pathways, contributing to cell proliferation and survival. CD97 interaction with tumor microenvironment components, including chondroitin sulfate and other adhesion molecules, can facilitate tumor growth and spread (2,6-9).