CD172g SIRPγ (signal regulatory protein γ), SIRPβ2
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 1 glycoprotein
T Cell
NK Cell
B Cell
Liver
55 / 55

Expression
CD172γ is expressed on a proportion of B cell, a majority of activated T cells and NK cells.  Expression is on the liver and at lower levels in many tissues, brain, heart, lung, pancreas, kidney, placenta and skeletal muscle.

Structure
MOLECULAR FAMILY NAME:  Belongs to the immunoglobulin gene superfamily. 

CD172γ is a single-pass type-1 354 aa transmembrane glycoprotein.  It contains a putative signal sequence, a long extracellular domain which contains a N-terminal 2 Ig-like C1-type domains and 1 Ig-like V-type domain, a transmembrane region and a short intracellular domain and no catalytic domain.  The structure is similar to that of CD172β in that it has a truncated cytoplasmic tail with no known motifs but it lacks the charged lysine residue required for interaction with DAP-12.  CD172γ is highly homologous to signal-regulatory protein, CD172β (SIRPβ), suggesting that it seems to be a new member of the SIRP family.  The protein encoded by CD172γ is a member of the signal-regulatory protein (SIRP) family and also belongs to the Ig superfamily.  

MOLECULAR MASS

POST-TRANSCRIPTIONAL MODIFICATION

Alternative splicing yields 2 different isoforms.  Isoform 1 has 3 C Ig-like C-type domains and isoform 2 lacks the 2 Ig-like C-typ2 domains and does not appear to be expressed on the cell surface.

POST-TRANSLATIONAL MODIFICATION: No information.

Ligands

LIGANDS AND MOLECULE ASSOCIATED WITH CD172γ

CD172γ binds with CD47 but with lower affinity than CD172α.



Function
CD172 (SIRP) family members are known to be involved in the negative regulation of receptor tyrosine-kinase coupled signaling processes and is involved in cell adhesion and costimulation.  CD172γ may play a role in T-cell-T-cell signaling via CD47 and thus influence T-cell behavior.  Ligation of CD47 by CD172γ was shown to induce apoptosis of T-cell lines, although not as efficiently as CD172α.  The binding of CD172γ was found to be dependent on the level of CD47 expression on target cells.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD172γ IN INTACT ANIMAL: No information.

Comments
MOLECULAR INTERACTIONS-
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD172γ: No information.

SUSBTRATES: No information.

ENZYMES WHICH MODIFY CD172γ: No information

ADDITIONAL INSIGHTS

For further information see Ichigotani, Y. et al (2000) J. Hum. Genet. 45: 378-382.


Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene55423Q9P1W8
Antibodies

Revised June 25, 2008


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