- Peptide (C)DVHLFDYVEPGNYSD, corresponding to amino acid residues 2-16 of rat CXCR7 (ACKR3) (Accession O89039). Extracellular, N-terminus.
- Human HL-60 and human Raji cells.
- Cell surface detection of CXCR7 in human HL-60 (A) and human Raji (B) living intact cells:____ Unstained cells
____ Cells + Anti-CXCR7 (ACKR3) (extracellular)-ATTO Fluor-488 Antibody (#ACR-037-AG), (5 μg/0.5x106 cells).
Chemokines are molecules that control the migration and positioning of the immune system cells. In addition to their function as chemo-attractants they have various other roles in the maturation of immune cells such as T-cell development in the thymus and homeostatic retention of immune cells in the bone marrow1.
Chemokines bind to chemokine receptors, members of the G-protein coupled receptor superfamily. They are comprised of seven transmembrane receptors with extracellular N-terminus, three extracellular and three intracellular loops and an intracellular C-terminus. One of the intracellular domains of the receptor couples with G proteins and begins a cascade of signal transduction2.
Until recently the CXCR-7 was an “orphan” receptor with its endogenous ligand unknown. This receptor is encoded by the CXCR7/RDC-1 gene which was mapped to mouse chromosome 1 and human chromosome 2. Homology has been shown with the viral gene ORF74 suggesting the receptor might signal without the binding of a ligand. Currently it is known that the chemokines CXCL12 and CXCL11 bind to CXCR-73.
CXCR-7 is tightly linked to the regulation of B cell development and differentiation indicating it might have a role in the formation of B memory cells4. CXCR-7 was also found to be associated with tumors where its levels are elevated in many tumor cell lines such as endothelial cells, fetal liver cells and placenta cells5. Despite this suggested role, there is growing evidence that this receptor does not function as a regular GPCR6.