– Signal-regulatory protein beta-2(SIRP-beta-2), is a monomeric single pass type I membrane glycoprotein, belongs to the SIRP/SHPS (CD172) family of the immunoglobulin (Ig) superfamily. The SIRP family are paired receptors that have similar extracellular domains but differing C-terminal domains and functions. A positively charged residue within the transmembrane domain, in analogy to SIRP-beta-1, is implicated to mediate interaction with the adaptor DAP12 protein, which contains immunoreceptor tyrosine-based activation motifs (ITAMs) . Proteins in the SIRP family are typically expressed in immune cells, especially in the myeloid lineages . Based on expression patterns, SIRPs are thought to have roles in immune regulation. SIRP family members role in innate immunity and host defense has potential significance as a therapeutic target in cancer and inflammation. There are currently no known mouse or rat homologs for this protein.