Actin (monomeric globular form) (G-actin)

G-actin, or monomeric globular actin, is a 42 kDa cytoskeletal protein that exists as a single, globular polypeptide with a deep cleft housing an ATP/ADP binding site[1][6][7]. It serves as the monomeric building block for filamentous actin (F-actin) and plays a central role in the formation and dynamic remodeling of the actin cytoskeleton, which underpins critical processes such as cell movement, muscle contraction, cytokinesis, and maintenance of cellular architecture. G-actin interacts with numerous actin-binding proteins and is a key mediator of actin filament dynamics, treadmilling, and nucleation[1][2][3]. Its dysfunction or dysregulation is implicated in a variety of pathological states including cancer, cardiac, and neurodegenerative diseases. While G-actin-binding drugs are mainly cytoskeletal research tools and not conventional therapeutics, their cellular effects underscore the essential and sensitive role of G-actin in cell biology[3][2].

Other names

Globular actinMonomeric actinG-actin

Inhibition of polymerization (cytochalasins, latrunculins bind G-actin and prevent its incorporation into F-actin) Promotion of polymerization or stabilization (jasplakinolide, phalloidin promotes or stabilizes polymerization into F-actin)