Fibers composed of MICROFILAMENT PROTEINS, which are predominately ACTIN. They are the smallest of the cytoskeletal filaments.

Synonyms: Actin Cytoskeleton, Actin Filament, Actin Filaments, Microfilament, Actin Microfilaments, Filament, Actin, Cytoskeleton, Actin, Microfilaments, Actin, Microfilaments, Cytoskeletons, Actin, Actin Cytoskeletons, Filaments, Actin, Microfilament, Actin, Actin Microfilament