Actin and myosin regulate cytoplasm stiffness in plant cells: a study using optical tweezers
Article first published online: 15 SEP 2009
© The Authors (2009). Journal compilation © New Phytologist (2009)
Volume 185, Issue 1, pages 90–102, January 2010
How to Cite
van der Honing, H. S., de Ruijter, N. C. A., Emons, A. M. C. and Ketelaar, T. (2010), Actin and myosin regulate cytoplasm stiffness in plant cells: a study using optical tweezers. New Phytologist, 185: 90–102. doi: 10.1111/j.1469-8137.2009.03017.x
- Issue published online: 1 DEC 2009
- Article first published online: 15 SEP 2009
- Received: 15 June 2009, Accepted: 26 July 2009
- cytoplasmic organization;
- cytoplasmic strand;
- optical tweezers;
- •Here, we produced cytoplasmic protrusions with optical tweezers in mature BY-2 suspension cultured cells to study the parameters involved in the movement of actin filaments during changes in cytoplasmic organization and to determine whether stiffness is an actin-related property of plant cytoplasm.
- •Optical tweezers were used to create cytoplasmic protrusions resembling cytoplasmic strands. Simultaneously, the behavior of the actin cytoskeleton was imaged.
- •After actin filament depolymerization, less force was needed to create cytoplasmic protrusions. During treatment with the myosin ATPase inhibitor 2,3-butanedione monoxime, more trapping force was needed to create and maintain cytoplasmic protrusions. Thus, the presence of actin filaments and, even more so, the deactivation of a 2,3-butanedione monoxime-sensitive factor, probably myosin, stiffens the cytoplasm. During 2,3-butanedione monoxime treatment, none of the tweezer-formed protrusions contained filamentous actin, showing that a 2,3-butanedione monoxime-sensitive factor, probably myosin, is responsible for the movement of actin filaments, and implying that myosin serves as a static cross-linker of actin filaments when its motor function is inhibited. The presence of actin filaments does not delay the collapse of cytoplasmic protrusions after tweezer release.
- •Myosin-based reorganization of the existing actin cytoskeleton could be the basis for new cytoplasmic strand formation, and thus the production of an organized cytoarchitecture.