CD197 CCR7 (chemokine [C-C motif] receptor 7) (*See available information under CD CKR), BLR2, EB11, CDw197
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 3 glycoprotein, 7 span
Thymocyte
Macrophage
T Cell
Dendritic Cell
NK Cell
B Cell
45 / 45

Expression
CD197 is expressed in various lymphoid tissues and activated B and T lymphocytes.          CD197 is expressed at high levels on most naive T cells and the CD62L-positive subset of memory T cells, B cells, NK cells and dendritic cells.  High levels of L-selectin/CD62L consist with their homing capacity to secondary lymphoid organs. Expression is on CD4 or CD8 single positive mature thymocytes and CD34+ macrophage progenitor cells.  Expression is strongly up-regulated in B cells infected with Epstein-Barr virus and T cells infected with herpesvirus 6 or 7.

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

CD197 is a multi-pass type-3, 7 span glycoprotein.  It contains an extracellular domain which contains 2 cysteines in the 2nd and 3rd extracellular loop domains forming a disulphide bond, a conserved DRY motif (A/S) (I/V) DR (Y/F) XXXX, where X represents hydrophobic residues in the 2nd extracellular domain and potential N-glycosylation sites in the N-terminal extracellular domain and the 3rd extracellular loop, 7 hydrophobic transmembrane-spanning domains and a cytoplasmic carboxyl terminal domain.  CD197, human and mouse, displays 86% aa identity.  The human gene is composed of 3 exons and 2 introns covering 12 kb.  This is unique because chemokine receptor genes were known to be composed of 1 exon.  CD197 is a chemokine receptor which are G-protein coupled receptors which forms a division of the leukocyte chemoattractant subfamily which is part of the rhodopsin family of GPCRs. 

MOLECULAR MASS
Cell Type Unreduced Reduced
45 kDa

POST-TRANSCRIPTIONAL MODIFICATION OF: No information.

POST-TRANSLATIONAL MODIFICATION: No information.


Ligands
LIGANDS AND MOLECULES ASSOCIATED WITH CD197

CD197 is associated with CCL19 and CCL21 and both are bound with high affinity.

Function
Chemokine receptors mediate the functions of chemokines which have several roles as inducers of cell movement and activation.  CD197 is a receptor for the MIP-3β chemokine.  CD197 and its chemokine ligands play crucial roles in the homing of naive T cells, antigen-loaded dendritic cells into secondary organs.  CD197-positive T cells activate dendritic cells to produce IL-12.  The T cells of mice lacking CCL21 cannot home to secondary lymphoid tissues and dendritic cells in these mice failed to localize in the lymphoid tissue.  Knockout mice show similar defects in lymphocytes and dendritic cell migration and homing leading to impaired cell-mediated and antibody responses.  Expression of CD197 identifies a subset of  memory T cells, designated central memory T cells which express high levels of CD62L.  These cells activate dendritic cells and home to secondary lymphoid tissue, but they lack the effector function.  This subset is distinguished from CD197-, CD62 low memory T cells and designated effector memory T cells, which carry out effector functions and migrate into peripheral tissues.  The receptor has been shown control the migration of memory T cells to inflamed tissues as well as stimulate dendritic cell maturation.  

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD197 IN INTACT ANIMAL:

CD197 is upregulated in B and T cells by infection with lymphotropic herpesvirus and may have a role in viral life cycles by affecting migratory homing properties of infected cells.  Surface expression of CD197 in leukemia cells from patients with adult T cell leukemia was found to be a positive correlation between the upregulation in leukemia cells and their lymphoid organs.  The results demonstrate the value of examining surface CD197 expression in understanding the migratory and functional properties of lymphoid cells in health and disease.  CD197 is a probable mediator of Epstein-Barr virus (EBV) or Burkitt's lymphoma receptor 2 (BLR2)  effects on B lymphocytes or of normal lymphocyte functions.  CD197 is a research reagent, distinguishing central memory from effector memory T cells.  Malignant T cells exprressing CD197 have a greater tendency to involve secondary lymphoid organs.


Comments
MOLECULAR INTERACTIONS -
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD197: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD197: No information.


Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene 1236P32248
Antibodies

Revised June 25, 2008


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