title: Microtubule sliding drives proplatelet elongation and is dependent on cytoplasmic dynein.
abstract: Bone marrow megakaryocytes produce platelets by extending long cytoplasmic protrusions, designated proplatelets, into sinusoidal blood vessels. Although microtubules are known to regulate platelet production, the underlying mechanism of proplatelet elongation has yet to be resolved. Here we report that proplatelet formation is a process that can be divided into repetitive phases (extension, pause, and retraction), as revealed by differential interference contrast and fluorescence loss after photoconversion time-lapse microscopy. Furthermore, we show that microtubule sliding drives proplatelet elongation and is dependent on cytoplasmic dynein under static and physiological shear stress by using fluorescence recovery after photobleaching in proplatelets with fluorescence-tagged β1-tubulin. A refined understanding of the specific mechanisms regulating platelet production will yield strategies to treat patients with thrombocythemia or thrombocytopenia.
authors.affiliation: Division of Translational Medicine and.
authors.forename: Markus
authors.identifier: http://orcid.org/0000-0002-2381-116X
authors.initials: M
authors.lastname: Bender
authors.affiliation: Hematology Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Platelet BioGenesis, Chestnut Hill, MA;
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Thon
authors.affiliation: School of Engineering and Applied Sciences, Harvard University, Cambridge, MA; Department of Bioengineering, McGill University, Montreal, QC, Canada;
authors.forename: Allen J
authors.initials: AJ
authors.lastname: Ehrlicher
authors.affiliation: Hematology Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA;
authors.forename: Stephen
authors.initials: S
authors.lastname: Wu
authors.affiliation: Platelet BioGenesis, Chestnut Hill, MA; School of Engineering and Applied Sciences, Harvard University, Cambridge, MA; Institute of Biotechnology, Vilnius University, Vilnius, Lithuania.
authors.forename: Linas
authors.initials: L
authors.lastname: Mazutis
authors.affiliation: Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA; Division of Neonatology, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden;
authors.forename: Emoke
authors.initials: E
authors.lastname: Deschmann
authors.affiliation: Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA;
authors.forename: Martha
authors.initials: M
authors.lastname: Sola-Visner
authors.affiliation: Hematology Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA; Platelet BioGenesis, Chestnut Hill, MA; Department of Surgery, Vascular Biology Program, Boston Children's Hospital, Boston, MA; and.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Italiano
authors.affiliation: Division of Translational Medicine and.
authors.forename: John H
authors.initials: JH
authors.lastname: Hartwig
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000166:cytology / Q000378:metabolism*; D002454:Cell Differentiation; D003593:Cytoplasm / Q000378:metabolism; D056445:Cytoplasmic Dyneins / Q000235:genetics / Q000378:metabolism*; D036681:Fluorescence Recovery After Photobleaching; D015870:Gene Expression; D040542:Mechanotransduction, Cellular; D008533:Megakaryocytes / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D008857:Microscopy, Interference; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism*; D061251:Primary Cell Culture; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013314:Stress, Mechanical; D034061:Thrombopoiesis / Q000235:genetics; D014404:Tubulin / Q000235:genetics / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D014404:Tubulin; D056445:Cytoplasmic Dyneins