Myosin II mutant Dictyostelium amoebae crawl more slowly than wild-type cells. Thus, myosin II must contribute to amoeboid locomotion. We propose that contractile forces generated by myosin II help the cell's rear edge to detach from the substratum and retract, allowing the cell to continue forward. To test this hypothesis, we measured the speed of wild-type and myosin II null mutant Dictyostelium cells on surfaces of varying adhesivity. As substratum adhesivity increased, the speed of myosin II null mutant cells decreased substantially compared to wild-type cells, suggesting that the mutant is less able to retract from sticky surfaces. Furthermore, interference reflection microscopy revealed a myosin-II-dependent contraction in wild-type but not null mutant cells that is consistent with a balance of adhesive and contractile forces in retraction. Although myosin II null mutant cells have a defect in retraction, pseudopod extension does not cause the cells to become elongated on sticky surfaces. This suggests a mechanism, based possibly on cytoskeletal tension, for regulating cell shape in locomotion. The tension would result from the transmission of tractional forces through the cytoskeletal network, providing the myosin II null mutant with a limited means of retraction and cell division on a surface.
A mechanical function of myosin II in cell motility
P.Y. Jay, P.A. Pham, S.A. Wong, E.L. Elson; A mechanical function of myosin II in cell motility. J Cell Sci 1 January 1995; 108 (1): 387–393. doi: https://doi.org/10.1242/jcs.108.1.387
Download citation file:
Advertisement
Cited by
Follow us on Instagram
Cell science is bursting with beautiful images and over on Instagram, we're showing them off!
Follow JCS and FocalPlane on Instagram for stories and techniques across cell biology.
Mole - The Corona Files
"There are millions of people around the world who continue to believe that the Terrible Pandemic is a hoax."
Mole continues to offer his wise words to researchers on how to manage during the COVID-19 pandemic.
Life after a Travelling Fellowship
Sina Krokowski is a postdoc in Andres Floto's lab, investigating the cell biology underlying host-pathogen interactions. In 2015, Sina used a Travelling Fellowship to visit the Carballido-López lab in Paris where she learned a new technique that was vital for her PhD. We caught up with Sina to hear about the ongoing impact of the trip on her scientific career since.
Upcoming grant deadlines
Grants awarded by The Company of Biologists help scientists travel, attend events and host sustainable activities. Make a note of the upcoming application deadlines and find out more about the grants on offer:
Sustainable Conferencing Grants
17 May 2021
Travelling Fellowships
31 May 2021
Scientific Meeting Grants
4 June 2021