title: Enucleation of human erythroblasts involves non-muscle myosin IIB.
abstract: Mammalian erythroblasts undergo enucleation, a process thought to be similar to cytokinesis. Although an assemblage of actin, non-muscle myosin II, and several other proteins is crucial for proper cytokinesis, the role of non-muscle myosin II in enucleation remains unclear. In this study, we investigated the effect of various cell-division inhibitors on cytokinesis and enucleation. For this purpose, we used human colony-forming unit-erythroid (CFU-E) and mature erythroblasts generated from purified CD34(+) cells as target cells for cytokinesis and enucleation assay, respectively. Here we show that the inhibition of myosin by blebbistatin, an inhibitor of non-muscle myosin II ATPase, blocks both cell division and enucleation, which suggests that non-muscle myosin II plays an essential role not only in cytokinesis but also in enucleation. When the function of non-muscle myosin heavy chain (NMHC) IIA or IIB was inhibited by an exogenous expression of myosin rod fragment, myosin IIA or IIB, each rod fragment blocked the proliferation of CFU-E but only the rod fragment for IIB inhibited the enucleation of mature erythroblasts. These data indicate that NMHC IIB among the isoforms is involved in the enucleation of human erythroblasts.
authors: Department of Hematology, Nephrology, and Rheumatology, Akita University Graduate School of Medicine, Akita, Japan.
authors: Kumi
authors: K
authors: Ubukawa
authors: Yong-Mei
authors: YM
authors: Guo
authors: Masayuki
authors: M
authors: Takahashi
authors: Makoto
authors: M
authors: Hirokawa
authors: Yoshihiro
authors: Y
authors: Michishita
authors: Miho
authors: M
authors: Nara
authors: Hiroyuki
authors: H
authors: Tagawa
authors: Naoto
authors: N
authors: Takahashi
authors: Atsushi
authors: A
authors: Komatsuda
authors: Wataru
authors: W
authors: Nunomura
authors: Yuichi
authors: Y
authors: Takakuwa
authors: Kenichi
authors: K
authors: Sawada
mesh_terms: D000577:Amides / Q000494:pharmacology; D000634:Aminoquinolines / Q000494:pharmacology; D002478:Cells, Cultured; D048749:Cytokinesis / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004900:Erythroblasts / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D015672:Erythroid Precursor Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004920:Erythropoiesis / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006576:Heterocyclic Compounds, 4 or More Rings / Q000494:pharmacology; D006801:Humans; D008840:Microfilament Proteins / Q000037:antagonists & inhibitors; D009218:Myosins / Q000037:antagonists & inhibitors; D024507:Nonmuscle Myosin Type IIA / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D024501:Nonmuscle Myosin Type IIB / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000037:antagonists & inhibitors; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors
chemical_list: D000577:Amides; D000634:Aminoquinolines; D004791:Enzyme Inhibitors; D006576:Heterocyclic Compounds, 4 or More Rings; D008840:Microfilament Proteins; C487513:NSC 23766; D010446:Peptide Fragments; D020033:Protein Isoforms; D011725:Pyridines; D011743:Pyrimidines; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; C108830:Y 27632; D049452:Green Fluorescent Proteins; C472645:blebbistatin; D054460:rho-Associated Kinases; D024507:Nonmuscle Myosin Type IIA; D024501:Nonmuscle Myosin Type IIB; D009218:Myosins; D020830:rac1 GTP-Binding Protein