CD158j KIR2DS2 (killer cell immunoglobulin-like receptor, short cytoplasmic tail, 2), NKAT5
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 1 glycoprotein
NK Cell
T Cell
50 / 50

Expression
CD158j is expressed on subsets of NK cells, on subsets of cytotoxic cells and some T cells.  Expression on individual NK cells is complex and several members of the KIR family.  The repertoire of KIR molecules varies among NK cells and is not determined solely by the HLA hapotypes.

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

CD158j is a single-pass type-1 glycoprotein   It contains an extracellular domain which contains 2 Ig-like C2-type domains (D1 and D2), a 304 aa transmembrane domain which is a charged lysine residue and a 39 aa shorft cytoplasmic domain with no ITIMs.  KIRs with short tails cytoplasmic tails are associated with NK cell triggering rather than inhibition.  CD158j revealed a 50 kDA protein. 

MOLECULAR MASS

POST-TRANSCRIPTIONAL MODIFICATION: No information.

POST-TRANSLATIONAL MODIFICATION: No information.


Ligands
LIGANDS AND MOLECULES ASSOCIATED WITH CD158j

CD158j binds the HLA-C molecule.

Function
CD158j is the receptor on NK cells for HLA-C alleles and is involved in the activation of NK cell mediated cytotoxicity but CD158j does not inhibit the activity of NK cells.  CD158j forms disulfide-linked homodimers of 2 p70 subunits.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD158j IN INTACT ANIMAL

It has been noted that KIR genes are variably present in the Caucasian population with the majority positive for inhibitory KIR.  A number of normal individuals and rheumatoid arthritis could be typed for either CD158j or CD158h, whereas patients with unequivocal vasculitis had a highly significant association with CD158j, suggesting that CD158j affects not the risk of developing RA but rather the risk of developing vascular complications.  HLA-C polymorphisms are receognized by CD158j family proteins.

Comments

Killer cell immunoglobulin (Ig)-like receptors (KIR), also called killer cell inhibitory receptors, are glycoproteins expressed in natural killer (NK) cells and some T cells.  The KIR family is estimated to include about 11 genes.  Some members of the KIR family bind to certain HLA class I deficient cell lines.  Ligation of such KIR by HLA class I molecules on target cells results in inhibition of the NK or T cell cytotoxic activity.  The inhibition could be disrupted by antibodies against membrane glycoproteins on NK cells that recognized HLA- and HLA-C.  Inhibitory KIRs are found in 3 distinct isoforms.  KIRs that recognize HLA-C are usually monomeric glycoproteins of about 58 kDa with 2 Ig-like domains (KIR2D).  KIRs that are reactive with HLA-B are approximately 70 kDa monomeric glycoproteins with 3 Ig-like domains (KIR3D).  The KIR family is further subdivided into forms with short and long intracytoplasmic tails.  The 1st and 2nd Ig domains in KIR2D are closely related in aa sequence to the 2nd and 3rd Ig domains in KIR3D. These 2 related Ig domains are called D1 and D2, respectively.  D0 is the 1st Ig domain in KIR3D.  KIR members vary in the length of the cytoplasmic tails.  Most of the long cytoplasmic tails, KIR2DL and KIR3DL, deliver an inhibitory signal and carry 2 immunoreceptor tyrosine-based inhibition motifs (ITIM) which recruit and activate protein tyrosine phosphates, SHP-1 and or SHP-2.  Other receptors, of about 50 kDa, with short cytoplasmic regions (KIR2DS and KIR3DS) are truncated before the 1st ITIM causing them to have no ITIMs.  They are are connected to a transmembrane region which includes a lysine residue and can activate NK or T cell responses.  The short tail associates with a disulfide dimer of 14 kDa. phosphoproteins called DAP12 which is also known as killer activating protein (KARAP).

MOLECULAR INTERACTIONS-
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD158j: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD158j: No information.



Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene 3807P43631
Antibodies

Revised June 25, 2008


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