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Distinct localizations and roles of non‐muscle myosin II during proplatelet formation and platelet release
Author(s) -
Badirou I.,
Pan J.,
Souquere S.,
Legrand C.,
Pierron G.,
Wang A.,
Eckly A.,
Roy A.,
Gachet C.,
Vainchenker W.,
Chang Y.,
Léon C.
Publication year - 2015
Publication title -
journal of thrombosis and haemostasis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.947
H-Index - 178
eISSN - 1538-7836
pISSN - 1538-7933
DOI - 10.1111/jth.12887
Subject(s) - myosin , microbiology and biotechnology , cytoplasm , cytoskeleton , organelle , myosin light chain kinase , biology , mitochondrion , actin , chemistry , biochemistry , cell
Summary Background At the end of maturation, megakaryocytes ( MKs ) form long cytoplasmic extensions called proplatelets ( PPT ). Enormous changes in cytoskeletal structures cause PPT to extend further, to re‐localize organelles such as mitochondria and to fragment, leading to platelet release. Two non‐muscle myosin II s ( NMII s) are expressed in MKs ; however, only NMII ‐A ( MYH 9), but not NMII ‐B ( MYH 10), is expressed in mature MKs and is implicated in PPT formation. Objectives To provide in vivo evidence on the specific role of NMII ‐A and IIB in MK PPT formation. Methods We studied two transgenic mouse models in which non‐muscle myosin heavy chain ( NMHC ) II ‐A was genetically replaced either by II ‐B or by a chimeric NMHCII that combined the head domain of II ‐A with the rod and tail domains of II ‐B. Results and Conclusions This work demonstrates that the kinetic properties of NM ‐ IIA , depending on the N‐terminal domain, render NMII ‐A the better NMII candidate to control PPT formation. Furthermore, the carboxyl‐terminal domain determines myosin II localization in the constriction region of PPT and is responsible for the specific role of NMII in platelet release.