CCR7/CCL21 migration on fibronectin is mediated by phospholipase Cgamma1 and ERK1/2 in primary T lymphocytes

J Biol Chem. 2010 Dec 10;285(50):38781-7. doi: 10.1074/jbc.M110.152173. Epub 2010 Oct 1.

Abstract

CCR7 binds to its cognate ligand, CCL21, to mediate the migration of circulating naive T lymphocytes to the lymph nodes. T lymphocytes can bind to fibronectin, a constituent of lymph nodes, via their β1 integrins, which is a primary mechanism of T lymphocyte migration; however, the signaling pathways involved are unclear. We report that rapid (within 2 min) and transient phosphorylation of ERK1/2 is required for T cell migration on fibronectin in response to CCL21. Conversely, prevention of ERK1/2 phosphorylation by inhibition of its kinase, MAPK/MEK, prevented T lymphocyte migration. Previous studies have suggested that phospholipase Cγ1 (PLCγ1) can mediate phosphorylation of ERK1/2, which is required for β1 integrin activation. Paradoxically, we found that inhibition of PLCγ1 phosphorylation by the general PLC inhibitor U73122 was associated with a delayed and reduced phosphorylation of ERK1/2 and reduced migration of T lymphocytes on fibronectin. To further characterize the relationship between ERK1/2 and PLCγ1, we reduced PLCγ1 levels by 85% using shRNA and observed a reduced phosphorylation of ERK1/2 and a significant loss of CCR7-mediated migration of T lymphocytes on fibronectin. In addition, we found that inhibition of ERK1/2 phosphorylation by U0126 resulted in a decreased phosphorylation of PLCγ1, suggesting a feedback loop between ERK1/2 and PLCγ1. Overall, these results suggest that the CCR7 signaling pathway leading to T lymphocyte migration on fibronectin is a β1 integrin-dependent pathway involving transient ERK1/2 phosphorylation, which is modulated by PLCγ1.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Movement
  • Chemokine CCL21 / metabolism*
  • Chemokines / metabolism
  • Chemotaxis
  • Fibronectins / metabolism*
  • Gene Expression Regulation, Enzymologic*
  • Humans
  • Integrin beta1 / metabolism
  • Mice
  • Mitogen-Activated Protein Kinase 1 / metabolism*
  • Mitogen-Activated Protein Kinase 3 / metabolism*
  • Phospholipase C gamma / metabolism*
  • Phosphorylation
  • Receptors, CCR7 / metabolism*
  • T-Lymphocytes / cytology*
  • T-Lymphocytes / metabolism

Substances

  • CCL21 protein, human
  • CCR7 protein, human
  • Chemokine CCL21
  • Chemokines
  • Fibronectins
  • Integrin beta1
  • Receptors, CCR7
  • MAPK1 protein, human
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Phospholipase C gamma