CD97

CD97 is a protein that in humans is encoded by the CD97 gene. It is a member of the adhesion G protein-coupled receptor (GPCR) family. These receptors are characterized by an extended extracellular region with a varying number of N-terminal epidermal growth factor (EGF)-like domains, which are important for binding with ligands and mediating cell-cell interactions. The CD97 protein plays a significant role in cell adhesion, cell signaling, and immune response modulation.

Structure

CD97 is a complex protein that consists of a large extracellular region, a seven-transmembrane domain typical of GPCRs, and a short cytoplasmic tail. The extracellular region contains several EGF-like domains, which are critical for the protein's interaction with its ligands. Among its known ligands are CD55 (decay-accelerating factor, DAF), which is involved in regulating complement activity, and chondroitin sulfate, which plays a role in cell adhesion and migration.

Function

The primary function of CD97 is to mediate cell-cell adhesion and communication. It is widely expressed in various cell types, including immune cells such as T cells, B cells, and macrophages, as well as in other tissues like the lung, liver, and kidney. Through its interaction with CD55, CD97 participates in the immune system's response by modulating the activity of the complement system, thus playing a role in protecting cells from complement-mediated damage.

CD97 is also implicated in the regulation of immune responses and inflammation. It has been shown to be involved in the migration of immune cells to sites of inflammation, a process crucial for the immune system's proper functioning.

Clinical Significance

Alterations in CD97 expression have been associated with various diseases, including cancers and inflammatory diseases. In cancer, overexpression of CD97 has been observed in several types of tumors, where it is thought to contribute to tumor growth, invasion, and metastasis. This is likely due to its role in cell adhesion and migration, which are key processes in the spread of cancer cells.

In inflammatory diseases, changes in CD97 expression can affect immune cell migration and the inflammatory response, potentially contributing to the pathogenesis of these conditions. Therefore, CD97 is considered a potential target for therapeutic interventions in cancer and inflammatory diseases.

Research Directions

Research on CD97 continues to explore its functions and mechanisms of action in health and disease. Understanding the precise roles of CD97 in cell signaling, immune response modulation, and disease progression could lead to the development of new therapeutic strategies targeting this receptor.