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Blood, 1 February 2006, Vol. 107, No. 3, pp. 973-979. Prepublished online as a Blood First Edition Paper on October 18, 2005; DOI 10.1182/blood-2005-05-2015. This Article Full Text Full Text (PDF) All Versions of this Article: 2005-05-2015v1 107/3/973    most recent 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 Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Redondo, P. C. Articles by Sage, S. O. Search for Related Content PubMed PubMed Citation Articles by Redondo, P. C. Articles by Sage, S. O. Related Collections Hemostasis, Thrombosis, and Vascular Biology Signal Transduction Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  HEMOSTASIS, THROMBOSIS, AND VASCULAR BIOLOGY A role for cofilin in the activation of store-operated calcium entry by de novo conformational coupling in human platelets Pedro C. Redondo, Matthew T. Harper, Juan A. Rosado, and Stewart O. Sage From the Department of Physiology, University of Extremadura, Cáceres, Spain; and the Department of Physiology, University of Cambridge, Cambridge, United Kingdom. Store-operated Ca2+ entry (SOCE) is a major mechanism for Ca2+ influx in platelets and other cells. De novo conformational coupling between elements in the plasma membrane and Ca2+ stores, where the actin cytoskeleton plays an important regulatory role, has been proposed as the most likely mechanism to activate SOCE in platelets. Here we have examined for the first time changes in platelet F-actin levels on a subsecond time scale. Using stopped-flow fluorimetry and a quenched-flow approach, we provide evidence for the involvement of cofilin in actin filament reorganization and SOCE in platelets. Thrombin (0.1 U/mL) evoked an initial decrease in F-actin that commenced within 0.1 second and reached a minimum 0.9 second after stimulation, prior to the activation of SOCE. F-actin then increased, exceeding basal levels approximately 2.5 seconds after stimulation. Thrombin also induced cofilin dephosphorylation and activation, which paralleled the changes observed in F-actin, and rapid Btk activation. Inhibition of cofilin dephosphorylation by LFM-A13 resulted in the loss of net actin depolymerization and an increased delay in SOCE initiation. These results suggest that cofilin is important for the rapid actin remodeling necessary for the activation of SOCE in platelets through de novo conformational coupling. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: G. E. Woodard, G. M. Salido, and J. A. Rosado Enhanced exocytotic-like insertion of Orai1 into the plasma membrane upon intracellular Ca2+ store depletion Am J Physiol Cell Physiol, June 1, 2008; 294(6): C1323 - C1331. [Abstract] [Full Text] [PDF] S. E Fiedler, M. Bajpai, and D. W Carr Identification and Characterization of RHOA-Interacting Proteins in Bovine Spermatozoa Biol Reprod, January 1, 2008; 78(1): 184 - 192. [Abstract] [Full Text] [PDF] B. T. Kile, A. D. Panopoulos, R. A. Stirzaker, D. F. Hacking, L. H. Tahtamouni, T. A. Willson, L. A. Mielke, K. J. Henley, J.-G. Zhang, I. P. Wicks, et al. Mutations in the cofilin partner Aip1/Wdr1 cause autoinflammatory disease and macrothrombocytopenia Blood, October 1, 2007; 110(7): 2371 - 2380. [Abstract] [Full Text] [PDF] S. L. Zhang, A. V. Yeromin, X. H.-F. Zhang, Y. Yu, O. Safrina, A. Penna, J. Roos, K. A. Stauderman, and M. D. Cahalan Genome-wide RNAi screen of Ca2+ influx identifies genes that regulate Ca2+ release-activated Ca2+ channel activity PNAS, June 13, 2006; 103(24): 9357 - 9362. [Abstract] [Full Text] [PDF]

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