Cofilin is ubiquitously expressed in eukaryotic cells where it binds to Actin, thereby regulating the rapid cycling of Actin assembly and disassembly, essential for cellular viability. Cofilin is a low molecular weight protein that binds to filamentous F-Actin by bridging two longitudinally-associated Actin subunits, changing the F-Actin filament twist. This process is allowed by the dephosphorylation of Cofilin Ser 3 by factors like opsonized zymosan. LIM kinase 1 (LIMK-1), a serine kinase, phosphorylates Cofilin and renders it unable to bind and depolymerize F-Actin.