SIRP alpha Recombinant Rabbit mAb (S-2505-8)

Signal-regulatory protein alpha (SIRPα, also known as CD172a or SHPS-1) is a type I transmembrane glycoprotein of the immunoglobulin superfamily, prominently expressed on myeloid cells, neurons, and stem cells, that functions as an inhibitory receptor by binding to the broadly expressed ligand CD47 (the “don’t eat me” signal) to negatively regulate innate immune effector functions such as macrophage phagocytosis of healthy host cells; upon CD47 engagement, phosphorylation of its cytoplasmic immunoreceptor tyrosine-based inhibitory motifs (ITIMs) recruits phosphatases like SHP-1 and SHP-2, thereby blocking actin cytoskeleton remodeling required for phagocytic activity, while structural studies have revealed its extracellular region contains three Ig-like domains (one V-set and two C1-set) and the interaction surface resembles antigen-receptor binding; in cancer, tumor cells exploit this CD47-SIRPα axis as an innate immune checkpoint to evade phagocytosis, making SIRPα a promising therapeutic target, especially in combination with anti-PD-1/PD-L1 therapies .