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Blood, 1 May 2008, Vol. 111, No. 9, pp. 4605-4616. Prepublished online as a Blood First Edition Paper on January 29, 2008; DOI 10.1182/blood-2007-10-118844. This Article Full Text (PDF) Supplemental Figure and Videos All Versions of this Article: blood-2007-10-118844v1 111/9/4605    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 Patel-Hett, S. Articles by Italiano, J. E. Search for Related Content PubMed PubMed Citation Articles by Patel-Hett, S. Articles by Italiano, J. E., Jr. Related Collections Related Article in Blood Online Social Bookmarking                   What's this?  Previous Article  |  Next Article  Submitted October 19, 2007 Accepted January 13, 2008 Visualization of microtubule growth in living platelets reveals a dynamic marginal band with multiple microtubules Sunita Patel-Hett, Jennifer L. Richardson, Harald Schulze, Ksenija Drabek, Natasha A. Isaac, Karin Hoffmeister, Ramesh A. Shivdasani, J. Chloe Bulinski, Niels Galjart, John H. Hartwig, and Joseph E. Italiano Jr.* Translational Medicine Division, Brigham and Women's Hospital, Boston, MA, United States Laboratory for Pediatric Molecular Biology, Charite Medical University, Berlin, Germany Department of Cell Biology and Genetics, Erasmus University, Rotterdam, Netherlands Department of Medicine, Dana Farber Cancer Institute, Boston, MA, United States Department of Biological Sciences, Columbia University, New York, NY, United States Vascular Biology Program, Department of Surgery, Children's Hospital, Boston, MA, United States * Corresponding author; email: jitaliano{at}rics.bwh.harvard.edu. The marginal band of microtubules maintains the discoid shape of resting blood platelets. Although studies of platelet microtubule coil structure conclude that it is composed of a single microtubule, no investigations of its dynamics exist. In contrast to previous studies, permeabilized platelets incubated with GTP-rhodamine-tubulin revealed tubulin incorporation at 7.9 +/-1.9 points throughout the coil, and anti-EB1 antibodies stained 8.7 +/- 2.0 sites, indicative of multiple free microtubules. To pursue this result, we expressed the microtubule plus-end marker EB3-GFP in megakaryocytes and examined its behavior in living platelets released from these cells. Time-lapse microscopy of EB3-GFP in resting platelets revealed multiple assembly sites within the coil and a bidirectional pattern of assembly. Consistent with these findings, tyrosinated tubulin, a marker of newly assembled microtubules, localized to resting platelet microtubule coils. These results suggest that the resting platelet marginal band contains multiple highly dynamic microtubules of mixed polarity. Analysis of microtubule coil diameters in newly formed resting platelets indicates that microtubule coil shrinkage occurs with aging. Additionally, activated EB3-GFP-expressing platelets exhibited a dramatic increase in polymerizing microtubules, which travel outward and into filopodia. Thus, the dynamic microtubules associated with the marginal band likely function during both resting and activated platelet states. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? Related Article in Blood Online: Platelet marginal bands: not so marginal Katya Ravid Blood 2008 111: 4423. [Full Text] [PDF]

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