Actin Dynamics

 

The fast and reversible polymerization of actin proteins into long filaments consisting of hundreds of subunits is the driving force for many types of cell motions. Actin filament growth proceeds via polymerization, depolymerization, ATP hydrolysis and release of phosphate. We are interested in understanding how the free energy of ATP hydrolysis is used by cells to power constant turnover of actin filaments.

 

We developed a theoretical description of average filament elongation rate and length fluctuations, under non-steady state conditions.

     

 

We are further interested in how proteins such as formins regulate actin polymerization. We have developed a quantitative model describing the elongation kinetics of actin filaments associated with formin and profilin. The model also rationalizes how filaments associated with formins with many such binding sites can exceed the “diffusion-limited” rate of bare actin.

 

 

References

 

D. B. Heisler, E. Kudryashova, D. O. Grinevich, C. Suarez, J. D. Winkelman, K. G. Birukov, S. R. Kotha, N. L. Parinandi, D. Vavylonis, D. R. Kovar, D. S. Kudryashov, "ACD toxin-produced actin oligomers poison formin-controlled actin polymerization," Science, 49:535-539 (2015).

Fujiwara, Vavylonis, and Pollard, Proc. Natl. Acad. Sci. USA 104, 8826–8832 (2007)

Vavylonis, Yang, and O’Shaughnessy, Proc. Natl. Acad. Sci. USA 102, 8543–8548 (2005)

Vavylonis, Kovar, O’Shaughnessy, and Pollard, Molecular Cell, 39 455 (2006).