![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
Vol. 17, Issue 7, 2855-2868, July 2006
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Department of Biology and Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454
Submitted February 15, 2006;
Revised March 16, 2006;
Accepted April 5, 2006
Monitoring Editor: David Drubin
Rapid turnover of actin structures is required for dynamic remodeling of the cytoskeleton and cell morphogenesis, but the mechanisms driving actin disassembly are poorly defined. Cofilin plays a central role in promoting actin turnover by severing/depolymerizing filaments. Here, we analyze the in vivo function of a ubiquitous actin-interacting protein, Aip1, suggested to work with cofilin. We provide the first demonstration that Aip1 promotes actin turnover in living cells. Further, we reveal an unanticipated role for Aip1 and cofilin in promoting rapid turnover of yeast actin cables, dynamic structures that are decorated and stabilized by tropomyosin. Through systematic mutagenesis of Aip1 surfaces, we identify two well-separated F-actin–binding sites, one of which contributes to actin filament binding and disassembly specifically in the presence of cofilin. We also observe a close correlation between mutations disrupting capping of severed filaments in vitro and reducing rates of actin turnover in vivo. We propose a model for balanced regulation of actin cable turnover, in which Aip1 and cofilin function together to "prune" tropomyosin-decorated cables along their lengths. Consistent with this model, deletion of AIP1 rescues the temperature-sensitive growth and loss of actin cable defects of tpm1
mutants.
The online version of this article contains supplemental material at MBC Online (http://www.molbiolcell.org).
Address correspondence to: Bruce L. Goode ( goode{at}brandeis.edu)
This article has been cited by other articles:
|
|
 |
|
  L. Gao and A. Bretscher Analysis of Unregulated Formin Activity Reveals How Yeast Can Balance F-Actin Assembly between Different Microfilament-based Organizations Mol. Biol. Cell, April 1, 2008; 19(4): 1474 - 1484. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Gunning, G. O'neill, and E. Hardeman Tropomyosin-Based Regulation of the Actin Cytoskeleton in Time and Space Physiol Rev, January 1, 2008; 88(1): 1 - 35. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Mseka, J. R. Bamburg, and L. P. Cramer ADF/cofilin family proteins control formation of oriented actin-filament bundles in the cell body to trigger fibroblast polarization J. Cell Sci., December 15, 2007; 120(24): 4332 - 4344. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Ren, J. Charlton, and P. N. Adler The flare Gene, Which Encodes the AIP1 Protein of Drosophila, Functions to Regulate F-Actin Disassembly in Pupal Epidermal Cells Genetics, August 1, 2007; 176(4): 2223 - 2234. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. G. Clark and D. C. Amberg Biochemical and Genetic Analyses Provide Insight Into the Structural and Mechanistic Properties of Actin Filament Disassembly by the Aip1p Cofilin Complex in Saccharomyces cerevisiae Genetics, July 1, 2007; 176(3): 1527 - 1539. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. B. Moseley and B. L. Goode The Yeast Actin Cytoskeleton: from Cellular Function to Biochemical Mechanism Microbiol. Mol. Biol. Rev., September 1, 2006; 70(3): 605 - 645. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Odorizzi The multiple personalities of Alix. J. Cell Sci., August 1, 2006; 119(Pt 15): 3025 - 3032. [Abstract] [Full Text] [PDF]
|
|
