Binds to F-actin and exhibits pH-sensitive F-actin depolymerizing activity (By similarity). Important for normal progress through mitosis and normal cytokinesis (By similarity). In conjunction with the subcortical maternal complex (SCMC), plays an essential role for zygotes to progress beyond the first embryonic cell divisions via regulation of actin dynamics (By similarity). Required for the centralization of the mitotic spindle and symmetric division of zygotes (By similarity). Plays a role in the regulation of cell morphology and cytoskeletal organization in epithelial cells (By similarity). Required for the up-regulation of atypical chemokine receptor ACKR2 from endosomal compartment to cell membrane, increasing its efficiency in chemokine uptake and degradation (By similarity). Required for neural tube morphogenesis and neural crest cell migration (By similarity). Can bind G- and F-actin in a 1:1 ratio of cofilin to actin (By similarity). It is a major component of intranuclear and cytoplasmic actin rods (By similarity). Interacts with the subcortical maternal complex (SCMC) via interaction with TLE6 and NLRP5 (By similarity). Interacts with C9orf72 (By similarity). Colocalizes with the actin cytoskeleton in membrane ruffles and lamellipodia. Detected at the cleavage furrow and contractile ring during cytokinesis. Almost completely in nucleus in cells exposed to heat shock or 10% dimethyl sulfoxide. Inactivated by phosphorylation on Ser-3. Phosphorylated on Ser-3 in resting cells. Dephosphorylated by PDXP/chronophin; this restores its activity in promoting actin filament depolymerization. The phosphorylation of Ser-24 may prevent recognition of the nuclear localization signal (By similarity). Phosphorylated via a ARRB1-RAC1-LIMK1-PAK1 cascade upon active ligand stimulation of atypical chemokine receptor ACKR2 (By similarity). Belongs to the actin-binding proteins ADF family.