HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Downey, GregoryP. Articles by Grinstein, S. Search for Related Content PubMed PubMed Citation Articles by Downey, GregoryP. Articles by Grinstein, S. Social Bookmarking                      What's this?

Volume 271, Number 35, Issue of August 30, 1996 pp. 21005-21011
©1996 by The American Society for Biochemistry and Molecular Biology, Inc.

---

Chemotactic Peptide-induced Activation of MEK-2, the Predominant Isoform in Human Neutrophils
INHIBITION BY WORTMANNIN

(Received for publication, May 26, 1995, and in revised form, June 14, 1996)

Gregory P. Downey , Jeffrey R. Butler ^¶ , John Brumell ^¶ , Niels Borregaard , Lars Kjeldsen , Andrea K. Sue-A-Quan and Sergio Grinstein ^¶

From the  Department of Medicine, Institute of Medical Science, and the  Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8 Canada, the  Granulocyte Research Laboratory, Rigshospitalet, DK-2100 Copenhagen, Denmark, and the ^¶ Division of Cell Biology, Research Institute, the Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada

Exposure of neutrophils to a variety of agonists including chemoattractant peptides and cytokines induces degranulation and activation of the oxidative burst which are required for bacterial killing. The signaling pathways regulating these important functions are incompletely characterized. Mitogen-activated protein (MAP) kinases, which include the extracellular signal-regulated kinases (ERKs), are activated rapidly in neutrophils, suggesting that they may regulate cell activation. We found that neutrophils express two isoforms of MAP/ERK kinase (MEK), mixed-function kinases that are responsible for phosphorylation and activation of ERK. Like MEK-1, MEK-2 was found to reside in the cytosol both before and after stimulation. Studies were undertaken to define the relative abundance and functional contribution of MEK-1 and MEK-2 in neutrophils and to characterize the signaling pathways leading to their activation. Although the abundance of the two isoforms was similar, the activity of MEK-2 was at least 3-fold greater than that of MEK-1. A rise in cytosolic [Ca²⁺] was insufficient for MEK stimulation, and blunting the [Ca²⁺] change with intracellular chelators failed to prevent receptor-mediated activation of either isoform, implying that cytosolic Ca²⁺ transients are not necessary. In contrast, both MEK-1 and MEK-2 were activated by exposure of cells to protein kinase C (PKC) agonists. Conversely, PKC antagonists inhibited the chemotactic stimulation of both isoforms, suggesting that PKC was required for their activation. Despite these similarities, clear differences were also found in the pathways leading to activation of the MEK isoforms. In particular, MEK-2 was considerably more sensitive than MEK-1 to the phosphatidylinositol 3-kinase inhibitor wortmannin. Phosphorylation and activation of ERK-1 and ERK-2 were also reduced by this inhibitor. In summary, MEK-2 is stimulated in formyl-methionyl-leucyl-phenylalanine-treated neutrophils, where it appears to be functionally the predominant isoform. The time course and inhibitor sensitivity of MEK-2 activation parallel those of several components of the microbicidal response, suggesting a signaling role of the MEK-ERK pathway.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				J. Y. Channon, K. A. Miselis, L. A. Minns, C. Dutta, and L. H. Kasper Toxoplasma gondii Induces Granulocyte Colony-Stimulating Factor and Granulocyte-Macrophage Colony-Stimulating Factor Secretion by Human Fibroblasts: Implications for Neutrophil Apoptosis Infect. Immun., November 1, 2002; 70(11): 6048 - 6057. [Abstract] [Full Text] [PDF]

				G. Cicchetti, P. G. Allen, and M. Glogauer CHEMOTACTIC SIGNALING PATHWAYS IN NEUTROPHILS: FROM RECEPTOR TO ACTIN ASSEMBLY Crit. Rev. Oral. Biol. Med., May 1, 2002; 13(3): 220 - 228. [Abstract] [Full Text]

				M. Berger, S. Budhu, E. Lu, Y. Li, D. Loike, S. C. Silverstein, and J. D. Loike Different Gi-coupled chemoattractant receptors signal qualitatively different functions in human neutrophils J. Leukoc. Biol., May 1, 2002; 71(5): 798 - 806. [Abstract] [Full Text] [PDF]

				M. Takami, V. Terry, and L. Petruzzelli Signaling Pathways Involved in IL-8-Dependent Activation of Adhesion Through Mac-1 J. Immunol., May 1, 2002; 168(9): 4559 - 4566. [Abstract] [Full Text] [PDF]

				M. O. Hannigan, L. Zhan, Y. Ai, A. Kotlyarov, M. Gaestel, and C.-K. Huang Abnormal Migration Phenotype of Mitogen-Activated Protein Kinase-Activated Protein Kinase 2-/- Neutrophils in Zigmond Chambers Containing Formyl-Methionyl-Leucyl-Phenylalanine Gradients J. Immunol., October 1, 2001; 167(7): 3953 - 3961. [Abstract] [Full Text] [PDF]

				J. P. Lian, L. Crossley, Q. Zhan, R. Huang, P. Coffer, A. Toker, D. Robinson, and J. A. Badwey Antagonists of Calcium Fluxes and Calmodulin Block Activation of the p21-Activated Protein Kinases in Neutrophils J. Immunol., February 15, 2001; 166(4): 2643 - 2650. [Abstract] [Full Text] [PDF]

				H. Ali, J. Ahamed, C. Hernandez-Munain, J. L. Baron, M. S. Krangel, and D. D. Patel Chemokine Production by G Protein-Coupled Receptor Activation in a Human Mast Cell Line: Roles of Extracellular Signal-Regulated Kinase and NFAT J. Immunol., December 15, 2000; 165(12): 7215 - 7223. [Abstract] [Full Text] [PDF]

				J. P. Lian, R. Huang, D. Robinson, and J. A. Badwey Activation of p90RSK and cAMP Response Element Binding Protein in Stimulated Neutrophils: Novel Effects of the Pyridinyl Imidazole SB 203580 on Activation of the Extracellular Signal-Regulated Kinase Cascade J. Immunol., October 15, 1999; 163(8): 4527 - 4536. [Abstract] [Full Text] [PDF]

				D. D. Browning, N. D. Windes, and R. D. Ye Activation of p38 Mitogen-activated Protein Kinase by Lipopolysaccharide in Human Neutrophils Requires Nitric Oxide-dependent cGMP Accumulation J. Biol. Chem., January 1, 1999; 274(1): 537 - 542. [Abstract] [Full Text] [PDF]

				M. Tardif, M.-J. Rabiet, T. Christophe, M.-D. Milcent, and F. Boulay Isolation and Characterization of a Variant HL60 Cell Line Defective in the Activation of the NADPH Oxidase by Phorbol Myristate Acetate J. Immunol., December 15, 1998; 161(12): 6885 - 6895. [Abstract] [Full Text] [PDF]

				M. H. Pillinger, C. Capodici, P. Rosenthal, N. Kheterpal, S. Hanft, M. R. Philips, and G. Weissmann Modes of action of aspirin-like drugs: Salicylates inhibit Erk activation and integrin-dependent neutrophil adhesion PNAS, November 24, 1998; 95(24): 14540 - 14545. [Abstract] [Full Text] [PDF]

				W. Zhong, Q. Zen, J. Tebo, K. Schlottmann, M. Coggeshall, and R. F. Mortensen Effect of Human C-Reactive Protein on Chemokine and Chemotactic Factor-Induced Neutrophil Chemotaxis and Signaling J. Immunol., September 1, 1998; 161(5): 2533 - 2540. [Abstract] [Full Text] [PDF]

				M. Kashiwada, Y. Shirakata, J.-I. Inoue, H. Nakano, K. Okazaki, K. Okumura, T. Yamamoto, H. Nagaoka, and T. Takemori Tumor Necrosis Factor Receptor-associated Factor 6 (TRAF6) Stimulates Extracellular Signal-regulated Kinase (ERK) Activity in CD40 Signaling Along a Ras-independent Pathway J. Exp. Med., January 19, 1998; 187(2): 237 - 244. [Abstract] [Full Text] [PDF]

				G. P. Downey, J. R. Butler, H. Tapper, L. Fialkow, A. R. Saltiel, B. B. Rubin, and S. Grinstein Importance of MEK in Neutrophil Microbicidal Responsiveness J. Immunol., January 1, 1998; 160(1): 434 - 443. [Abstract] [Full Text] [PDF]

				L. Zheng, J. Eckerdal, I. Dimitrijevic, and T. Andersson Chemotactic Peptide-induced Activation of Ras in Human Neutrophils Is Associated with Inhibition of p120-GAP Activity J. Biol. Chem., September 12, 1997; 272(37): 23448 - 23454. [Abstract] [Full Text] [PDF]

				G. Daum, U. Hedin, Y. Wang, T. Wang, and A. W. Clowes Diverse Effects of Heparin on Mitogen-Activated Protein Kinase–Dependent Signal Transduction in Vascular Smooth Muscle Cells Circ. Res., July 19, 1997; 81(1): 17 - 23. [Abstract] [Full Text]

				P. H. Naccache, S. Levasseur, G. Lachance, S. Chakravarti, S. G. Bourgoin, and S. R. McColl Stimulation of Human Neutrophils by Chemotactic Factors Is Associated with the Activation of Phosphatidylinositol 3-Kinase gamma J. Biol. Chem., July 28, 2000; 275(31): 23636 - 23641. [Abstract] [Full Text] [PDF]

				C.-i. Lee, K. Miura, X. Liu, and J. L. Zweier Biphasic Regulation of Leukocyte Superoxide Generation by Nitric Oxide and Peroxynitrite J. Biol. Chem., December 8, 2000; 275(50): 38965 - 38972. [Abstract] [Full Text] [PDF]

				S. Bechoua and L. W. Daniel Phospholipase D Is Required in the Signaling Pathway Leading to p38 MAPK Activation in Neutrophil-like HL-60 Cells, Stimulated by N-Formyl-methionyl-leucyl-phenylalanine J. Biol. Chem., August 17, 2001; 276(34): 31752 - 31759. [Abstract] [Full Text] [PDF]