Interleukin-8 receptors R1 and R2 activate mitogen-activated protein kinases and induce c-fos, independent of Ras and Raf-1 in Chinese hamster ovary cells.
Many of the biological effects of interleukin-8 (IL-8) are realized by binding to the two seven-transmembrane receptors IL-8 R1 and IL-8 R2. IL-8 R1 is activated only by IL-8, while IL-8 R2 is activated by IL-8, GROalpha, and a few other alpha chemokines. In addition to the well-known chemoattractant function, IL-8 is also angiogenic and mitogenic. IL-8 R1 and R2 have been shown to interact with Galphai2 and Galpha16, resulting in the activation of several mitogen-activated protein kinases. We have investigated IL-8 R1 and IL-8 R2 regulated upstream mediators and downstream effects of extracellularly responsive kinase (ERK) signaling pathways by expressing the individual receptors in a heterologous system. Our results demonstrate the following in CHO cells stably expressing either IL-8 R1 or R2 receptors: (a) IL-8 activates ERK and ERK kinases (MEK) through R1. Both IL-8 and GROalpha activate ERK and MEK through R2, whereas MIP-1alpha, a beta chemokine, does not activate these kinases through either of these receptors. (b) ERK activation is inhibited by pertussis toxin and MEK1 inhibitor. (c) ERK activation is independent of the upstream mediators Ras and Raf-1. (d) The downstream effects of ERK activation result in an increase of c-fos mRNA through both R1 and R2 receptors.
Shyamala
V
V
Chiron Corporation, Emeryville, California 94608, USA. shyamala@cc.chiron.com
Khoja
H
H
D000818:Animals; D015703:Antigens, CD / Q000502:physiology*; D016466:CHO Cells; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002460:Cell Line; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D054360:Chemokine CXCL1; D019743:Chemokines, CXC; D002630:Chemotactic Factors / Q000502:physiology; D006224:Cricetinae; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D006133:Growth Substances / Q000502:physiology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D016209:Interleukin-8 / Q000378:metabolism*; D019402:Macrophage Inflammatory Proteins / Q000502:physiology; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D037342:Pertussis Toxin; D011493:Protein Kinase C / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis* / Q000235:genetics; D019908:Proto-Oncogene Proteins c-raf / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D018123:Receptors, Interleukin / Q000502:physiology*; D023062:Receptors, Interleukin-8A; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D010738:Type C Phospholipases / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D018631:ras Proteins / Q000502:physiology*
D015703:Antigens, CD; C475829:CXCL1 protein, human; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D054360:Chemokine CXCL1; D019743:Chemokines, CXC; D002630:Chemotactic Factors; D004791:Enzyme Inhibitors; D005419:Flavonoids; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D016209:Interleukin-8; D019402:Macrophage Inflammatory Proteins; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D018123:Receptors, Interleukin; D023062:Receptors, Interleukin-8A; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D019908:Proto-Oncogene Proteins c-raf; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D010738:Type C Phospholipases; D018631:ras Proteins; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one