SIRP beta 1A Products

Description

Signal-regulatory protein beta 1a (SIRP beta 1a) is a disulfide-linked type I membrane glycoprotein that 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 (1). Members of this family are characterized by an extracellular region containing a V-set Ig domain containing a J-like sequence and two C1-set Ig domains. Positively charged residues within the transmembrane domain mediate interactions with DAP12 proteins which contain immunoreceptor tyrosine-based activation motifs (ITAMs) (3). Proteins in the SIRP family are typically expressed in cells of monocyte, macrophage or dendritic lineages (4). Mouse SIRP beta 1a shares 57% and 59% amino acid sequence identity with human SIRP beta 1 and rat SIRP alpha, respectively. SIRP beta 1 has a relatively short cytoplasmic region and lacks the signaling motifs for association with phosphatases. However, formation of the SIRP beta 1/DAP12 complex in myeloid cells induce tyrosine phosphorylation, mitogen-activated protein kinase activation, and cellular activation (5, 6). Engagement of SIRP beta 1 by specific monoclonal antibodies promoted Fc gamma receptor-dependent or -independent phagocytosis in mouse peritoneal macrophages (7). Surfactant protein D (Sp-D) has been shown to bind SIRP alpha and SIRP beta 1 in a calcium-dependent and sugar-specific manner on a distinct binding site from CD47 (8). Although the SIRP beta 1 extracellular regions share a high degree of homology with the SIRP alpha, SIRP beta 1 has been shown not to bind CD47 (9).

Bioinformatics

Uniprot	NP001002898
Product By Gene ID	320832
Alternate Names	SIRP beta 1a SIRPB1A