gaktin

Gaktin is a fictional cytoskeletal protein introduced in educational materials and simulation datasets to illustrate actin-like polymer dynamics. It is not observed in nature; the term is used for teaching and modeling purposes.

Biochemical properties and structure: Gaktin monomers are modeled as ~45 kDa globular proteins that bind ATP and assemble into polar filaments. In the hypothetical filament, subunits add to the barbed end with a slow hydrolysis-coupled turnover. The monomer exhibits an actin-like fold with an ATP-binding pocket and four subdomains, but the sequence is distinct from actin to emphasize divergence.

Filament properties and interactions: The filaments provide tracks for hypothetical motor proteins and help maintain cell shape in the imagined organism. Gaktin-binding proteins regulate assembly and disassembly; severing and capping proteins control filament length.

Genetics and expression: In the model organism, the gaktin gene is normally expressed during cell growth and redistributed under stress; expression is modulated by regulatory networks analogous to actin in real systems.

Research and educational use: Gaktin is studied primarily through computer simulations, structural modeling, and classroom demonstrations. In silico experiments explore polymerization kinetics, filament mechanics, and interactions with motor proteins.

See also: Actin, Cytoskeleton, Motor protein, Filament.