Involvement of myosin in intracellular motility and cytomorphogenesis in Micrasterias
Version of Record online: 2 JAN 2013
© The Author(s) Journal compilation © 2003 International Federation for Cell Biology
Cell Biology International
Volume 27, Issue 12, pages 977–986, December 2003
How to Cite
Oertel, A., Holzinger, A. and Lütz-Meindl, U. (2003), Involvement of myosin in intracellular motility and cytomorphogenesis in Micrasterias. Cell Biology International, 27: 977–986. doi: 10.1016/j.cellbi.2003.07.004
- Issue online: 2 JAN 2013
- Version of Record online: 2 JAN 2013
- Received 10 April 2003, revised 9 June 2003, accepted 17 July 2003
- 2,3-butanedione monoxime (BDM);
- 1-(5-iodonaphthalene-1-sulfonyl)-1H-hexhydro-1.4-diazapine (ML7);
- N-ethylmaleimide (NEM)
Myosin was detected on Western blots of Micrasterias denticulata extracts by use of antibodies from different sources. Inhibitors with different targets of the actomyosin system, such as the myosin ATPase-blockers N-ethylmaleimide (NEM) and 2,3-butanedione monoxime (BDM), or the myosin light chain kinase inhibitor 1-(5-iodonaphthalene-1-sulfonyl)-1H-hexhydro-1,4-diazapine (ML7), had similar effects on intracellular motility during cell development in the green alga Micrasterias, thus pointing towards a participation of myosin in these processes. The drugs markedly altered the mode of postmitotic nuclear migration, slowed down cytoplasmic streaming, changed cell pattern development and prevented normal chloroplast distribution and spreading into the growing semicell. In addition, an increase and dilatations in ER cisternae and marked morphological changes of the Golgi system were observed by transmission electron microscopy after exposure of growing cells to BDM.
Neither BDM nor ML7 exhibited any effect on the distribution or arrangement of the cortical F-actin network nor on the F-actin basket around the nucleus, characteristic of untreated growing Micrasterias cells (J Cell Sci 107 (1994) 1929). This is particularly interesting since BDM caused disintegration of the microtubule system co-localized to the F-actin cage during normal nuclear migration. Together with the fact that other microtubules not connected to the F-actin system remained uninfluenced by BDM, this observation is evidence of an integrative function of myosin between the cytoskeleton elements.