title: Effect of spectrin dimer on actin polymerization.
abstract: Spectrin dimer is shown to influence the polymerization behaviour of actin. The polymerization of both Mg2+- and Ca2+-actin is regulated by an enhancement in the rate of nucleation and a fragmentation of preformed actin filaments. In addition, spectrin decreases the critical concentration of Ca2+-actin but not that of Mg2+-actin. This suggests that the two types of actin may differ in their interaction with spectrin dimer probably due to the different conformations. Band 4.1 elevates the effects of spectrin under non-equilibrium conditions but its contribution is less at steady state.
mesh_terms: D000199:Actins; D000818:Animals; D001665:Binding Sites; D001704:Biopolymers; D001798:Blood Proteins; D002118:Calcium; D055598:Chemical Phenomena; D002621:Chemistry; D003598:Cytoskeletal Proteins; D008274:Magnesium; D008565:Membrane Proteins; D009479:Neuropeptides; D011817:Rabbits; D013049:Spectrin
chemical_list: D000199:Actins; D001704:Biopolymers; D001798:Blood Proteins; D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D009479:Neuropeptides; C028841:erythrocyte membrane band 4.1 protein; C120557:erythrocyte membrane protein band 4.1-like 1; D013049:Spectrin; D008274:Magnesium; D002118:Calcium