What is the function of cofilin in actin filament dynamics?
Disassembly pathways must balance assembly to allow shape change during migration and division. Cofilin, also called ADF, 15 to 19 kilodalton protein conserved from yeast to mammals, directly severs and depolymerizes actin. Binding preference for ADP F actin, prevalent in older filament regions away from ATP cap, induces 5 degree reduction in helical twist per subunit from 167 to 162 degrees, weakening longitudinal contacts and increasing filament compliance. At boundaries between cofilin decorated and bare segments mechanical stress concentrates leading to breakage. Severing multiplies filame
Ref: Lodish et al., Molecular Cell Biology, 9th ed., Chapter 18: Cofilin Severing and Actin Turnover.
