CD57 HNK-1 (human natural killer-1)
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 2 glycoprotein
NK Cell
Brain
T Cell
Neural Cell
B Cell
Nervous system
110 / 110

Expression
CD57 is present on a subset of NK cells, neural tissues, brain and T cells.  Red blood cells, granulocytes, monocytes and platelets do not express CD57.  The antigen is expressed on receptors in the nervous system.  In chicken, CD57 has been identified on integrins.

Structure
MOLECULAR FAMILY NAME: Belongs to the glycosyltransferase gene family.

CD57 is a single-pass type-2 334 aa glycosylation.  It contains an extracellular domain which contains 3 potential N-glycosylation sites, a transmembrane domain and a short cytoplasmic domain.  CD57 is a carbohydrate structure consisting of a sulfated trisaccharide 3-O-sulfoglucuronic acid β1-3Gal β1-4GlcNAc.  CD57 may attach to several glycoproteins, including CD56, myelin glycoprotein PO and neural cell adhesion molecule L1.  It is an oligosaccharide antigenic determinant present on a variety of polypeptides, lipids and chondroitin sulfate (CS) proteoglycans in the nervous system.  The polypeptides associated with the antigen on leukocytes have not been characterized in detail.  The structure of CD57 as carried by a glycolipid is a 3'-sulfated glucuronic acid and the COOH of the glucuronic acid is important for the epitope.  The antigen is conserved across species.

MOLECULAR MASS
Cell Type Unreduced Reduced
110 kDa

POST-TRANSCRIPTIONAL MODIFICATION: No information.

POST-TRANSLATIONAL MODIFICATION: No information.


Ligands
CD57 binds to CD62 L- selectin and CD62 P-selectin but not E-selectin in a Ca2+ -dependent manner and is involved in homophilic interactions of PO.  CD57 binds to the 2nd globular domain of the E8 fragment of laminin.

Function
CD57 functions in cell-cell adhesion via laminin and L- and P selectin.  As part of myelin glycoprotein, CD57 probably maintains the structural integrity of myelin by homophilic adhesion.  Myelinated Schwann cells associated with motor but not sensory axons express CD57 on myelin-associated glycoprotein (MAG).  IL-1 activated brain microvascular endothelial cells collect a CD57-bearing glycolipid that has been implicated in the L selectin dependent binding of lyphocytes.  CD57+ T cells are implicated as suppressors of T cell responses.  In vitro, CD4+ CD57+ T cells do not promote differentiation of B cells into antibody producing cells and both CD4+CD57+ and CD8+CD57+ T cells display poor proliferation responses.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD57 IN INTACT ANIMAL

CD57 is a NK cell marker and a target of autoabodies in peripheral neuropathy.  It is expressed on some solid tumors such as well differentiated prostate cancers and uveal and cutaneous melanoma.

Comments
MOLECULAR INTERACTIONS-
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD57: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD57: No information.


Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene27087Q9P2W7
Antibodies

Revised June 25, 2008


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