UMMS Affiliation

Department of Physiology

Publication Date


Document Type



Acrylic Resins; Animals; Cell Movement; Cells, Cultured; Embryo, Mammalian; Fibroblasts; Mice; Mutation; Nonmuscle Myosin Type IIB


Life Sciences | Medicine and Health Sciences


Although myosin II is known to play an important role in cell migration, little is known about its specific functions. We have addressed the function of one of the isoforms of myosin II, myosin IIB, by analyzing the movement and mechanical characteristics of fibroblasts where this protein has been ablated by gene disruption. Myosin IIB null cells displayed multiple unstable and disorganized protrusions, although they were still able to generate a large fraction of traction forces when cultured on flexible polyacrylamide substrates. However, the traction forces were highly disorganized relative to the direction of cell migration. Analysis of cell migration patterns indicated an increase in speed and decrease in persistence, which were likely responsible for the defects in directional movements as demonstrated with Boyden chambers. In addition, unlike control cells, mutant cells failed to respond to mechanical signals such as compressing forces and changes in substrate rigidity. Immunofluorescence staining indicated that myosin IIB was localized preferentially along stress fibers in the interior region of the cell. Our results suggest that myosin IIB is involved not in propelling but in directing the cell movement, by coordinating protrusive activities and stabilizing the cell polarity.

DOI of Published Version



Mol Biol Cell. 2004 Mar;15(3):982-9. Epub 2003 Dec 29. Link to article on publisher's site

Journal/Book/Conference Title

Molecular biology of the cell

Related Resources

Link to Article in PubMed

PubMed ID