Thermodynamic Regulation of Actin Polymerization

Published

June 1, 2001

Author(s)

P S. Niranjan, J G. Forbes, S C. Greer, J Dudowicz, Karl Freed, Jack F. Douglas

Abstract

A Flory-Huggins-type lattice model of actin polymerization under equilibrium conditions is employed to analyze new spectroscopic measurements for the extent of actin polymerization diameter} as a function of temperature T, salt concentration [KC1], and the initial concentration of actin monomers [G_o]. The theory subsumes existing mechanisms for actin monomer initiation, dimerization, and chain propagation. The extent of polymerization diameter} increases with T to an unanticipated maximum, and the calculations explain this unusual effect as arising from a competition between monomer activation, which diminishes upon heating, and propagating chain growth, which increases upon heating. The actin polymerization is described as a rounded phase transition, and the associated polymerization temperature T_p depends strongly, but nearly linearly on [G_o]and [KC1] over the concentration regimes investigated. Our findings support the suggestion that physicochemical changes can complement regulatory proteins in controlling actin polymerization in living systems.

Citation

Journal of Chemical Physics

Volume

114

Issue

No. 24

Pub Type

Journals

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Keywords

Flory-Huggins-type lattice model

Citation

Niranjan, P. , Forbes, J. , Greer, S. , Dudowicz, J. , Freed, K. and Douglas, J. (2001), Thermodynamic Regulation of Actin Polymerization, Journal of Chemical Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=851976 (Accessed March 13, 2025)