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Blood, 1 November 2005, Vol. 106, No. 9, pp. 2952-2961. Prepublished online as a Blood First Edition Paper on August 2, 2005; DOI 10.1182/blood-2005-03-1062. This Article Full Text (PDF) All Versions of this Article: 2005-03-1062v1 106/9/2952    most recent Alert me when this article is cited Alert me if a correction is posted 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 Rights and Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Stork, P. J Articles by Dillon, T. J Search for Related Content PubMed PubMed Citation Articles by Stork, P. J Articles by Dillon, T. J Social Bookmarking                   What's this?  Previous Article  |  Next Article  Submitted March 17, 2005 Accepted June 17, 2005 Multiple roles of Rap1 in hematopoietic cells: complementary versus antagonistic functions Philip J Stork* and Tara J Dillon Vollum Institute, Oregon Health & Science University, Portland, OR, USA * Corresponding author; email: stork{at}ohsu.edu. Small G proteins serve as critical control points in signal transduction, integrating a wide range of stimuli to dictate discrete cellular outcomes. The outcomes of small G protein signaling can both potentiate and antagonize each other. Studies in hematopoietic cells have uncovered multiple functions for the small G protein Rap1. Because Rap1 can regulate cell proliferation, differentiation, and cell adhesion through distinct mechanisms, it serves as a paradigm for the need for tight cellular control of small G protein function. Rap1 has received recent attention for its role in enhancing integrin-dependent signals. This action of Rap1 augments a variety of processes that characterize hematopoietic cell function including aggregation, migration, extravasation, and homing to target tissues. Rap1 may also regulate cellular differentiation and proliferation via pathways that are distinct from those mediating adhesion, and involve regulation of the MAP kinase or ERK cascade. These actions of Rap1 occur in selected cell types to enhance or diminish ERK signaling depending on the expression pattern of the MAP kinase kinase kinases of the Raf family: Raf-1 and B-Raf. This review will examine the functions of Rap1 in hematopoietic cells, and focus on three cellular scenarios where the multiple actions of Rap1 function have been proposed. Recent studies implicating Rap1 in the maturation of megakaryocytes, the pathogenesis of CML and activation of peripheral T cells will receive particular attention. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

	Copyright © 2005 by American Society of Hematology         Online ISSN: 1528-0020