SIRPalpha Extracellular Domain (human, recombinant)

Signal regulatory protein alpha (SIRPalpha) is an inhibitory transmembrane receptor encoded by SIRPA in humans. It is composed of three extracellular immunoglobulin-like (Ig-like) domains, a single transmembrane region, and a cytoplasmic domain that contains four tyrosine residues with immunoreceptor tyrosine-based inhibitory motifs (ITIMs) that are essential to SIRPalpha interaction with the Src homology region 2 (SH2) domain-containing phosphatases SHP-1 and SHP-2. SIRPalpha is expressed on monocytes, macrophages, granulocytes, subsets of dendritic cells in lymphoid tissues, some bone marrow progenitor cells, and neurons. Binding of CD47 (Cay-32085), a receptor expressed on healthy cells but often overexpressed in cancer cells, to SIRPalpha induces phosphorylation of the SIRPalpha ITIMs, coupling to SHP-1 or SHP-2, and repression of immune cell activation and phagocytosis. Knockout of Sirpa increases dopaminergic neuronal loss in the substantia nigra pars compacta and enhances striatal microglia activation in a mouse model of MPTP-induced Parkinson's disease. Sirpa-/- mice exhibit increased age-related podocyte injury and proteinuria compared with wild-type mice. SIRPA expression is decreased in patients with focal segmental glomerular sclerosis and in mouse models of renal injury induced by puromycin aminonucleoside (Cay-15509), doxorubicin (Cay-15007), or streptozotocin (Cay-13104). Cayman's SIRPalpha Extracellular Domain (human, recombinant) protein can be used for ELISA. This protein consists of 351 amino acids, has a calculated molecular weight of 39 kDa, and a predicted N-terminus of Glu31 after signal peptide cleavage. By SDS-PAGE, under reducing conditions, the apparent molecular mass of this protein is 45 to 50 kDa due to glycosylation.Synonyms: CD172A, CD172 Antigen-like Family Member A, MyD-1 Antigen, SHPS-1, SHP Substrate 1, Signal Regulatory Protein alpha. Purity: >98% estimated by SDS-PAGE. Endotoxin Testing: <1.0 EU/µg, determined by the LAL endotoxin assay. Source: Active recombinant human C-terminal His-tagged SIRPalpha expressed in HEK293 cells. Amino Acids: 31-370. MW: 39 kDa. Formulation: (Request formulation change), Lyophilized from sterile PBS, pH 7.4. UniProt Accession #: P78324-2.