Signal-regulatory protein beta-2 (SIRPB2)

Signal-regulatory protein beta-2 (SIRPB2) is a member of the signal regulatory protein (SIRP) family within the immunoglobulin superfamily. SIRPB2 is expressed under normal physiological conditions in macrophages and granulocytes, both at the mRNA and protein levels[1][3][5]. It functions as a positive regulator of innate immunity, recruiting the immune activating adaptor protein DAP12, which enables activation pathways such as increased cell adhesion, differentiation, and cancer cell phagocytosis. SIRPB2 is structurally similar to SIRPB1 but contains two V-set Ig domains rather than one V- and two C1-set domains. Key functional activity depends on a charged lysine residue (lysine 202) in its transmembrane domain, necessary for DAP12 association. Unlike inhibitory relatives such as SIRPA, SIRPB2 does not have tyrosine-phosphorylation sites and thus does not signal via conventional phosphatase pathways. Recent research positions SIRPB2 as a novel costimulatory target for innate immunotherapy, with potential clinical relevance in cancer treatment by enhancing anticancer immunity via innate immune cells. As of current knowledge, SIRPB2 has not been directly targeted by approved drugs, nor have specific safety concerns or biomarkers been defined. It remains an emerging molecule of interest for immuno-oncology research[1][3][5].

Other names

PTPN1LPTPNS1L3DJ776F14.2protein tyrosine phosphatase non-receptor type substrate 1-like 3protein tyrosine phosphatase non-receptor type substrate proteinSIRP-beta-2

Stimulation via immune activating adaptor protein DAP12; Positive regulation of phagocytosis and immune cell adhesion