title: Role of nucleotide hydrolysis in the polymerization of actin and tubulin.
abstract: Here is presented a short survey of the main aspects of the involvement of nucleotide hydrolysis in the polymerization of actin and microtubules: 1) XTP hydrolysis is not tightly coupled to the polymerization process; XTP hydrolysis and phosphate release generate an unstable XDP-polymer which is maintained at steady state, in the presence of XTP, by terminal XTP-subunits; this feature can generate patterns of phase transitions of the polymer between stable and unstable conformations; 2) Interactions between subunits are involved in the mechanism of XTP hydrolysis; 3) XTP cleavage on the polymer is followed by the slow release of Pi; the structural and thermodynamic characteristics of the transient XDP-Pi-polymer may play a crucial role in the regulation of the dynamics of microtubules and actin filaments.
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D000818:Animals; D006868:Hydrolysis; D008870:Microtubules / Q000378:metabolism; D009711:Nucleotides / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D011108:Polymers; D011817:Rabbits; D013552:Swine; D013816:Thermodynamics; D014404:Tubulin / Q000378:metabolism*
chemical_list: D000199:Actins; D009711:Nucleotides; D010710:Phosphates; D011108:Polymers; D014404:Tubulin