Fesselin a Synaptopodin-like Protein Stimulates Actin Nucleation and Polymerization

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Brent Beall (Creator)

Joseph M. Chalovich (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Fesselin is a proline-rich actin binding protein that has recently been isolated from smooth muscle [Leinweber B. D. Fredricksen R. S. Hoffman D. R. and Chalovich J. M. (1999) J. Muscle Res. Cell Motil. 20 539–545]. Fesselin is similar to synaptopodin [Mundel P. Heid H. W. Mundel T. M. Krüger M. Reiser J. and Kriz W. (1997) J. Cell Biol. 139 193–204] in terms of its size isoelectric point and sequence although synaptopodin is not present in smooth muscle. The function f fesselin is unknown. Evidence is presented here that fesselin accelerates the polymerization of actin. Fesselin was effective on actin isolated from either smooth or skeletal muscle at low ionic strength and in the presence of 100 mM KCl. At low ionic strength fesselin decreased the time for 50% polymerization to about 1% of that in the absence of fesselin. The lag phase characteristic of the slow nucleation process of polymerization was eliminated as the fesselin concentration was increased from very low levels. Fesselin did not alter the critical concentration for actin but did increase the rate of elongation by ≈3-fold. The increase in elongation rate constant is insufficient to account for the total increase in polymerization rate. It is likely that fesselin stabilizes the formation of actin nuclei. Time courses of actin polymerization at varied fesselin concentrations and varied ctin concentrations were simulated by increasing the rate of nucleation and both the forward and reverse rate constants for elongation.Originally published Biochemistry Vol. 40 No. 47 Nov 2001

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Publication

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Biochemistry. 40:47(November 2001) p. 14525-14529.

Language: English

Date: 2011

Keywords

fesselin, actin polymerization, elongation rate

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