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Cytoplasmic elongation and rupture in megakaryoblastic leukemia cells via activation of adhesion and motility by staurosporine on fibronectin‐bound substratum
Author(s) -
Yamazaki Yoshimitsu,
Sanokawa Reiko,
Fujita Yasuko,
Zhou Deshan,
Kawasaki Kazunori,
Tanaka Hideoki,
Komatsu Tsunehiko,
Nagasawa Toshiro,
Oka Syuichi
Publication year - 1999
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/(sici)1097-4652(199905)179:2<179::aid-jcp8>3.0.co;2-r
Subject(s) - microbiology and biotechnology , cytoplasm , fibronectin , staurosporine , cytochalasin , filopodia , microfilament , cytoskeleton , cytochalasin b , elongation , motility , cytochalasin d , chemistry , biology , actin , protein kinase c , kinase , cell , biochemistry , extracellular matrix , materials science , ultimate tensile strength , metallurgy
Human megakaryoblastic leukemia Meg‐01 cells were attached to fibronectin (FN)‐coated substratum, on which remarkable spreading and cytoplasmic elongation was induced by treatment with a protein kinase inhibitor, staurosporine (stp). This effect was inhibited by RGDS and was also not seen on FN‐lacking substratum. The extended cytoplasm had swollen terminals and nodes, which contained GpIIb and β‐thromboglobulin, occasionally included α granules, and tended to form particles (2–5 μm) after rupture of the narrowed cytoplasm. Among other protein kinase modulators tested, only K252a promoted the elongation, while calphostin, herbimycin, TPA, and calyculin suppressed it. The cells began to migrate soon after addition of stp, with attachment to the substratum held at some sites during the migration. This tethered movement seemed to cause the cytoplasmic elongation and the rupture into particles. The elongation was retarded by pretreating the cells with cytochalasin A and Clostridium C3 toxin but not with demecolcine. Actin microfilaments in the stp‐treated Meg‐01 cells accumulated in the filopodia and periphery of the extended cytoplasm, in which vinculin was colocalized as adhesion plaques. The microtubules were longitudinally oriented through the cytoplasmic extension and showed no ring profile in the nodes and particles. Thus, stp in the presence of FN appears to stimulate reorganization of actin‐based cytoskeleton and formation of focal contacts in Meg‐01 cells. This leads to the activation of cell adhesion and motility, and then cytoplasmic elongation and rupture into particles. J. Cell. Physiol. 179:179–192, 1999. © 1999 Wiley‐Liss, Inc.