CXCR7 mediated Giα independent activation of ERK and Akt promotes cell survival and chemotaxis in T cells

Cell Immunol. 2012;272(2):230-41. doi: 10.1016/j.cellimm.2011.09.015. Epub 2011 Oct 20.

Abstract

Chemokine receptors CXCR7 and CXCR4 bind to the same ligand stromal cell derived factor-1alpha (SDF-1α/CXCL12). We assessed the downstream signaling pathways mediated by CXCL12-CXCR7 interaction in Jurkat T cells. All experiments were carried out after functionally blocking the CXCR4 receptor. CXCL12, on binding CXCR7, induced phosphorylation of extra cellular regulated protein kinases (ERK 1/2) and Akt. Selective inhibition of each signal demonstrated that phosphorylated ERK 1/2 is essential for chemotaxis and survival of T cells whereas activation of Akt promotes only cell survival. Another interesting finding of this study is that CXCL12-CXCR7 interaction under normal physiological conditions does not activate the p38 pathway. Furthermore, we observed that the CXCL12 signaling via CXCR7 is Giα independent. Our findings suggest that CXCR7 promotes cell survival and does not induce cell death in T cells. The CXCL12 signaling via CXCR7 may be crucial in determining the fate of the activated T cells.

MeSH terms

  • Cell Death / genetics
  • Cell Death / physiology
  • Cell Survival / genetics
  • Cell Survival / physiology*
  • Cells, Cultured
  • Chemokine CXCL12 / metabolism
  • Chemotaxis / genetics
  • Chemotaxis / physiology*
  • Down-Regulation
  • Enzyme Activation
  • Extracellular Signal-Regulated MAP Kinases / metabolism*
  • GTP-Binding Protein alpha Subunits, Gi-Go / metabolism*
  • Humans
  • Jurkat Cells
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Phosphorylation
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Receptors, CXCR / genetics
  • Receptors, CXCR / metabolism*
  • Receptors, CXCR4 / antagonists & inhibitors
  • Receptors, CXCR4 / genetics
  • Receptors, CXCR4 / metabolism
  • Signal Transduction / genetics
  • Signal Transduction / physiology
  • T-Lymphocytes / cytology
  • T-Lymphocytes / metabolism*
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • ACKR3 protein, human
  • CXCR4 protein, human
  • Chemokine CXCL12
  • Receptors, CXCR
  • Receptors, CXCR4
  • Proto-Oncogene Proteins c-akt
  • Extracellular Signal-Regulated MAP Kinases
  • Mitogen-Activated Protein Kinase 3
  • p38 Mitogen-Activated Protein Kinases
  • GTP-Binding Protein alpha Subunits, Gi-Go