Int J Biol Sci 2013; 9(8):778-791. doi:10.7150/ijbs.6459 This issue Cite
Research Paper
1. Bio Imaging and Cell Dynamics Research Center,
2. Bio Remodeling and Gene Therapy Lab., School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea,
3. Department of Marine Biology, Chosun University, Gwangju, 501-759, Korea
4. Department of Alternative Medicine, Nambu University, Gwangju 506-706, Korea
We previously reported a novel interaction between v-Crk and myosin-1c, and demonstrated that this interaction is essential for cell migration, even in the absence of p130CAS. We here demonstrate a role for Crk-myosin-1c interaction in cell adhesion and spreading. Crk-knockout (Crk‑/‑) mouse embryo fibroblasts (MEFs) exhibited significantly decreased cell spreading and reduced Rac1 activity. A stroboscopic analysis of cell dynamics during cell spreading revealed that the cell-spreading deficiency in Crk‑/‑ MEFs was due to the short protrusion/retraction distances and long persistence times of membrane extensions. The low activity of Rac1 in Crk‑/‑ MEFs, which led to delayed cell spreading in these cells, is consistent with the observed defects in membrane dynamics. Reintroduction of v-Crk into Crk‑/‑ MEFs rescued these defects, restoring cell-spreading activity and membrane dynamics to Crk+/+ MEF levels, and normalizing Rac1 activity. Knockdown of myosin-1c by introduction of small interfering RNA resulted in a delay in cell spreading and reduced Rac1 activity to low levels, suggesting that myosin-1c also plays an essential role in cell adhesion and spreading. In addition, deletion of the v-Crk SH3 domain, which interacts with the myosin-1c tail, led to defects in cell spreading. Overexpression of the GFP-myosin-1c tail domain effectively inhibited the v-Crk-myosin-1c interaction and led to a slight decrease in cell spreading and cell surface area. Collectively, these findings suggest that the v-Crk-myosin-1c interaction, which modulates membrane dynamics by regulating Rac1 activity, is crucial for cell adhesion and spreading.
Keywords: v-Crk, myosin-1c, cell adhesion, cell spreading