CD194 

CCR4 (chemokine [C-C motif] receptor 4) (*See available information under CD CKR)

Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 3 glycoprotein, 7 span
Macrophage
Thymus
Leukocyte
T Cell
Platelet
Basophil
Brain
Endothelial Cell
NK Cell
Monocyte
Peripheral blood
41 / 41

Expression

CD194 is predominantly expressed in the thymus, in perpherial blood leukocytes, including mostly on CD4+ CD25+ regulatory T cells, activated NK cells, macrophages, basophils, monocytes and in platelets.  Expression is at lower levels in the spleen but no expression in prostate, testis, ovary, small instestine and colon.  Expression is detected also in macrophages, IL-2-activated natural killer cells and skin-homing memory T cells, mostly the ones expressing the cutaneous lymphocyte antigen (CLA) T cells regardless of their Th1 or Th2 phenotype.  There is expression in the brain microvascular and coronary artery endothelial cells.



Structure
MOLECULAR FAMILY NAME: Belongs to the chemokine receptor family.

CD194 is a multi-pass type-3, 7 span 360 aa glycoprotein.  It contains an extracellular domain which contains 1 N-terminal loop with no N-glycosylation site but 2 N-glycosylation sites are present in the second extracellular loop, 7 transmembrane-spanning domain and a cytoplasmic carboxyl terminal domain.  CD194 is a chemokine receptor which are G-protein coupled receptors which forms a division of the leukocyte chemoattractant subfamily which is party of the rhodopsin family of GPCRs.

MOLECULAR MASS

POST-TRANSCRIPTIONAL MODIFICATION: No information.

POST-TRANSLATIONAL MODIFICATION: No information.



Ligands
LIGANDS AND MOLECULE ASSOCIATED WITH CD194

CD194 is high affinity receptor for CCL17 (TARC) and CCL22 (MDC).

Function
CD194 is a high affinity receptor for the C-C chemokine - MIP1, RANTES, TARC and MCP-1.  Chemokines are a small polypeptide, structurally related molecules that regulate cell trafficking of various types of leukocytes.  The chemokines also play fundamental roles in the development, homeostasis, and function of the immune system.  They have effects on cells of the central nervous system as well as on endothelial cells involved in angiogenesis or angiostasis.  The activity of this receptor is mediated by G proteins that activate a phosphatidylinositol-calcium second messenger system. 

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD194 IN INTACT ANIMAL:

CD194 can function as a chemoattractant homing receptor on circulating memory lymphocytes and as a coreceptor for some primary HIV-2 isolates and can mediate hippocampal-neuron survival in CNS.  They may also be involved in the termination of immune reactions because it is expressed on the surface of T regulatory cells.  CD194 blockade has potential as a therapeutic treatment of inflammation.

Comments
Although CD194 has been reserved for CCR4, no assignment was made at HLDA8 because at the time there were no confirmed antibodies.

MOLECULAR INTERACTIONS-
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD194: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD194: No information.

Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene 1233P51679
Antibodies

Revised June 25, 2008


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