SRCR

SRCR stands for scavenger receptor cysteine-rich, a designation used for a family of extracellular protein domains and the proteins that contain one or more of these motifs. The SRCR domain is typically about 90 to 110 amino acids long and is stabilized by multiple conserved cysteine residues that form disulfide bonds. In many proteins, SRCR domains occur in tandem and are combined with other modules, such as mucin-like regions or collagenous domains, creating a variety of extracellular receptors and secreted proteins.

SRCR-containing proteins are primarily involved in innate immunity and cell-surface adhesion. They often function as pattern-recognition receptors that can bind diverse ligands, including pathogens, apoptotic cells, and components of the extracellular matrix. Through ligand interactions, SRCR proteins can mediate cell adhesion, endocytosis or phagocytosis, and can influence inflammatory signaling pathways.

In humans and other vertebrates, SRCR-containing proteins include membrane-bound receptors such as CD5 and CD6, as well as secreted or soluble proteins like SALSA (gp340). Other receptors with SRCR domains contribute to pathogen recognition by macrophages and dendritic cells. The SRCR superfamily is evolutionarily ancient, and its proteins display a range of domain architectures across species, reflecting diversification of immune functions.

Research on SRCR-containing proteins focuses on understanding ligand specificity, structural features, and the roles these receptors play in health and disease. Their involvement in host defense and inflammatory processes also makes them of interest as potential therapeutic targets or biomarkers.