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Science 334 (6063): 1710-1713

Copyright © 2011 by the American Association for the Advancement of Science

Direct Redox Regulation of F-Actin Assembly and Disassembly by Mical

Ruei-Jiun Hung,1 Chi W. Pak,2 Jonathan R. Terman1,*

Abstract: Different types of cell behavior, including growth, motility, and navigation, require actin proteins to assemble into filaments. Here, we describe a biochemical process that was able to disassemble actin filaments and limit their reassembly. Actin was a specific substrate of the multidomain oxidation-reduction enzyme, Mical, a poorly understood actin disassembly factor that directly responds to Semaphorin/Plexin extracellular repulsive cues. Actin filament subunits were directly modified by Mical on their conserved pointed-end, which is critical for filament assembly. Mical posttranslationally oxidized the methionine 44 residue within the D-loop of actin, simultaneously severing filaments and decreasing polymerization. This mechanism underlying actin cytoskeletal collapse may have broad physiological and pathological ramifications.

1 Departments of Neuroscience and Pharmacology and Neuroscience Graduate Program, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
2 Department of Biochemistry, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.

* To whom correspondence should be addressed. E-mail: jonathan.terman{at}

Semaphorin 4D/Plexin-B1-Mediated M-Ras GAP Activity Regulates Actin-Based Dendrite Remodeling through Lamellipodin.
G.-i. Tasaka, M. Negishi, and I. Oinuma (2012)
J. Neurosci. 32, 8293-8305
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