A formin dimer (blue and green) takes several steps (left) and then changes to screw mode (right).

On page 889, Shemesh et al. suggest how formin builds actin filaments without tangling them. Formin, according to the new theory, slowly winds the filament and then undoes the twist with one big slip.

Formin caps the barbed ends of actin filaments, yet allows more monomers to be added. It has been proposed that a formin dimer works as if climbing stairs. The formin dimer initially contacts the terminal actin monomers but then releases its grip on the actin monomer second from the top, allowing it to bind a new actin monomer. When that new actin monomer is added, the free half of the formin dimer attaches to it. The other half of formin then releases its actin, and so on.

The model made sense but did...

The Rockefeller University Press
2005
The Rockefeller University Press
2005
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