Where AC proteins (red) bind, the structure of an actin filament (yellow) resembles its depolymerizing end.

Proteins that take apart actin filaments are hardly creative, according to Galkin et al. (page 1057), who show that destabilizing proteins induce structural states that are normally seen at the depolymerizing end of actin.

That end—the so-called pointed end—normally depolymerizes in the cell even as actin monomers are added at the other “barbed” end. This treadmilling is disturbed by ADF/cofilin (AC) proteins, which tear down actin filaments near the leading edge of migrating cells. The authors used electron microscopy and three-dimensional reconstructions to investigate how AC proteins promote instability and dismantle filaments.

AC-bound filaments looked like the pointed ends of naked actin filaments. Both were missing a contact between subdomain (SD) 2 of one actin monomer and SD1 of the monomer just above it in the filament....

The Rockefeller University Press
2003
The Rockefeller University Press
2003
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