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) Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted 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 Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Li, H.-L. Articles by Puré, E. Search for Related Content PubMed PubMed Citation Articles by Li, H.-L. Articles by Puré, E. Social Bookmarking                      What's this?

Volume 272, Number 29, Issue of July 18, 1997 pp. 18200-18208
©1997 by The American Society for Biochemistry and Molecular Biology, Inc.

Syk Is Required for BCR-mediated Activation of p90Rsk, but Not p70S6k, via a Mitogen-activated Protein Kinase-independent Pathway in B Cells

(Received for publication, March 27, 1997, and in revised form, May 7, 1997)

Hsiu-Ling Li , Mark S. Forman , Tomohiro Kurosaki and Ellen Puré

From the Wistar Institute, Philadelphia, Pennsylvania 19104 and the  Department of Molecular Genetics, Institute for Hepatic Research, Kansai Medical University, Moriguchi 570, Japan

The tyrosine kinases Syk and Lyn are activated in B lymphocytes following antibody induced cross-linking of the B cell receptor for antigen (BCR). It has been suggested that activation of Syk is dependent on Lyn. We tested this hypothesis by comparing the phosphorylation and activation of several downstream effector molecules in parental DT40, DT40Syk and DT40Lyn B cells. The phosphorylation and activation of p90Rsk was ablated in Syk-deficient B cells but unaffected in Lyn-deficient B cells while the phosphorylation/activation of Ras GTPase activating protein (Ras GAP) and mitogen activated protein (MAP) kinase required both Syk and Lyn. Thus, these data indicate that Syk can be activated in the absence of Lyn after BCR cross-linking and results in the activation of p90Rsk via a MAP kinase-independent pathway in DT40Lyn cells. We also demonstrated that BCR mediates the activation of p70S6k. However, activation of p70S6k in DT40Syk and DT40Lyn cells was comparable with that observed in parental cells. Thus, either Syk or Lyn may be sufficient for activation of p70S6k, or activation of p70S6k occurs independently of both Syk and Lyn. The kinase activity of Syk was required for the phosphorylation/activation of each of these downstream effector molecules but only the phosphorylation of Ras GAP was affected in cells expressing a mutant of Syk in which tyrosines 525 and 526 were substituted to phenlyalanines.

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

This article has been cited by other articles:

				M. Jacob, L. Todd, M. F. Sampson, and E. Pure Dual role of Cbl links critical events in BCR endocytosis Int. Immunol., April 1, 2008; 20(4): 485 - 497. [Abstract] [Full Text] [PDF]

				S. Lavens, E. A. Faust, F. Lu, M. Jacob, M. Leta, P. M. Lieberman, and E. Pure Identification of Protein Tyrosine Kinases Required for B-Cell- Receptor-Mediated Activation of an Epstein-Barr Virus Immediate-Early Gene Promoter J. Virol., August 15, 2004; 78(16): 8543 - 8551. [Abstract] [Full Text] [PDF]

				U. D. Bajpai, K. Zhang, M. Teutsch, R. Sen, and H. H. Wortis Bruton's Tyrosine Kinase Links the B Cell Receptor to Nuclear Factor {kappa}B Activation J. Exp. Med., May 15, 2000; 191(10): 1735 - 1744. [Abstract] [Full Text] [PDF]

				J.-i. Abe, M. Okuda, Q. Huang, M. Yoshizumi, and B. C. Berk Reactive Oxygen Species Activate p90 Ribosomal S6 Kinase via Fyn and Ras J. Biol. Chem., January 21, 2000; 275(3): 1739 - 1748. [Abstract] [Full Text] [PDF]

				T. M. Yankee, L. M. Keshvara, S. Sawasdikosol, M. L. Harrison, and R. L. Geahlen Inhibition of Signaling Through the B Cell Antigen Receptor by the Protooncogene Product, c-Cbl, Requires Syk Tyrosine 317 and the c-Cbl Phosphotyrosine-Binding Domain J. Immunol., December 1, 1999; 163(11): 5827 - 5835. [Abstract] [Full Text] [PDF]

				A. Craxton, A. Jiang, T. Kurosaki, and E. A. Clark Syk and Bruton's Tyrosine Kinase Are Required for B Cell Antigen Receptor-mediated Activation of the Kinase Akt J. Biol. Chem., October 22, 1999; 274(43): 30644 - 30650. [Abstract] [Full Text] [PDF]

				M. Fujimoto, J. C. Poe, P. J. Jansen, S. Sato, and T. F. Tedder CD19 Amplifies B Lymphocyte Signal Transduction by Regulating Src-Family Protein Tyrosine Kinase Activation J. Immunol., June 15, 1999; 162(12): 7088 - 7094. [Abstract] [Full Text] [PDF]

				H.-L. Li, W. W. Davis, E. L. Whiteman, M. J. Birnbaum, and E. Pure The tyrosine kinases Syk and Lyn exert opposing effects on the activation of protein kinase Akt/PKB in B lymphocytes PNAS, June 8, 1999; 96(12): 6890 - 6895. [Abstract] [Full Text] [PDF]

				H.-L. Li, W. Davis, and E. Pure Suboptimal Cross-linking of Antigen Receptor Induces Syk-dependent Activation of p70S6 Kinase through Protein Kinase C and Phosphoinositol 3-Kinase J. Biol. Chem., April 2, 1999; 274(14): 9812 - 9820. [Abstract] [Full Text] [PDF]

				L. M. Keshvara, C. C. Isaacson, T. M. Yankee, R. Sarac, M. L. Harrison, and R. L. Geahlen Syk- and Lyn-Dependent Phosphorylation of Syk on Multiple Tyrosines Following B Cell Activation Includes a Site That Negatively Regulates Signaling J. Immunol., November 15, 1998; 161(10): 5276 - 5283. [Abstract] [Full Text] [PDF]

				C. Venkataraman, N. Muthusamy, S. Muthukkumar, and S. Bondada Activation of Lyn, Blk, and Btk But Not Syk in CD72-Stimulated B Lymphocytes J. Immunol., April 1, 1998; 160(7): 3322 - 3329. [Abstract] [Full Text] [PDF]