|CD172b||SIRPβ1(signal regulatory protein β1)|
|Molecule Type||Antigen Expression||Molecular Weight|
Min / Max
|Non-lineage Restricted Molecule|
Type 1 glycoprotein
|110 / 110|
120 / 120
|CD172β is expressed on monocytes, granulocytes, dendritic cells, myeloid and neural cells. Expression is also on the brain, kidney and testis.|
|MOLECULAR FAMILY NAME: Belongs to the immunoglobulin gene superfamily.|
CD172β is a single-pass type-1 398 aa transmembrane glycoprotein. It contains an extracellular domain which is 90% identical to CD172α (excluding the signal sequence), contains 2 Ig-like C-type domains and 1 Ig-like V-type domain, a transmembrane domain which contains a positively charged lysine residue that is critical to its interaction with DAP-12 and a short cytoplasmic domain which consists of only a few intracellular residues and is functionally insignificant and lacks the sequence motifs capable of recruiting SHP-1 and SHP-2 which is present in CD172α. The protein encoded by CD172β is a member of the signal-regulatory-protein (SIRP) family. The family have been shown to recruit SH2 domain containing protein phosphatase 1 (SHP-1) and SHP-2 and to regulate receptor tyrosine kinase-coupled signaling but not in CD172β. One SIRP of unknown function, designated CD172β, associates with the signal transduction molecule DAP12, (CD172β/DAP12) complex formation which is required for efficient cell-surface expression.
Alternative splicing yields 2 different isoforms.
CD172β is N-glycosylated.
|LIGANDS AND MOLECULE ASSOCIATED WITH CD172β|
CD172β associates with DAP12 to mediate cellular activation.
|CD172 (SIRP) family members are receptor type transmembrane glycoprotien known to be involved is a Ig-like cell surface receptor involved in the negative regulation of receptor tyrosine has functional-kinase-coupled signaling processes. CD172β has activating functions in macrophages via constitutive association with DAP-12 (KARAP) homodimers. Phosphorylation of DAP-12 intracellular immunoreceptor tyrosine-based activating (ITAM) enables association with the tyrosine kinase Syk. This complex activates MAPK-MEK pathways and contributes to cellular activation in myeloid cells. This protein was found to interact with TYROBP/DAP12, a protein bearing ITIM motifs and is also reported to participate in the recruitment of tyrosine kinase SYK. Stimulation of CD172β/DAP12 induces tyrosine phosphorylation, mitogen-activated protein kinase activation and cellular activation. In a recent study, mAb ligation of CD172β was found to enhance transmigration of polymorphonuclear cells. However in this study, no association with DAP-12 was found but a smaller protein of 10 kDa coprecipitated with CD172β. |
BIOCHEMICAL ACTIVITY: No information.
DISEASE RELEVANCE AND FUNCTION OF CD172β IN INTACT ANIMAL: No information.
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD172β: No information.
SUBSTRATES: No information.
ENZYMES WHICH MODIFY CD172β: No information.
For further information see Dietrich, J. et al (2000) J. Immunol. 164: 9-12.
Database accession numbers
Revised June 25, 2008