The chemokine monocyte chemotactic protein 1 triggers Janus kinase 2 activation and tyrosine phosphorylation of the CCR2B receptor.
The chemokines are a growing family of low m.w., 70- to 80-residue proinflammatory cytokines that operate by interacting with G protein-coupled receptors. Chemokines are involved in cell migration and in the activation of specific leukocyte subsets. Using the Mono Mac 1 monocytic cell line, we show that monocyte chemotactic protein 1 (MCP-1) triggers activation of the Janus kinase 2 (JAK2)/STAT3 pathway and CCR2 receptor tyrosine phosphorylation. Both Ca2+ mobilization and cell migration are blocked in Mono Mac 1 cells by tyrphostin B42, a specific JAK2 kinase inhibitor. Within seconds of MCP-1 activation, JAK2 phosphorylates CCR2 at the Tyr139 position and promotes JAK2/STAT3 complex association to the receptor. This MCP-1-initiated phosphorylation and association to JAK2 is also observed in CCR2B-transfected HEK293 cells. In contrast, when a CCR2B Tyr139Phe mutant is expressed in HEK293 cells, it is not phosphorylated in tyrosine and triggers neither JAK2/STAT3 activation nor Ca2+ mobilization in response to MCP-1. These results implicate the tyrosine kinase pathway in early chemokine signaling, suggesting a key role for this kinase in later events.
Mellado
M
M
Department of Immunology and Oncology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científica-Universidad Autónoma de Madrid, Spain.
Rodríguez-Frade
J M
JM
Aragay
A
A
del Real
G
G
Martín
A M
AM
Vila-Coro
A J
AJ
Serrano
A
A
Mayor
F
F
Martínez-A
C
C
D019943:Amino Acid Substitution / Q000235:genetics; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D018932:Chemokine CCL2 / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D053614:Janus Kinase 2; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D054390:Receptors, CCR2; D019707:Receptors, Chemokine / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D018121:Receptors, Cytokine / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects; D014443:Tyrosine / Q000235:genetics / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
C515334:CCR2 protein, human; D018932:Chemokine CCL2; D011518:Proto-Oncogene Proteins; D054390:Receptors, CCR2; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine; D010566:Virulence Factors, Bordetella; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D002118:Calcium