Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

This Article Full Text Full Text (PDF, 374K) PPT slides of all figures Alert me when this article is cited Citation Map Services Email this article Similar articles in this journal Similar articles in PubMed Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Skoble, J. Articles by Welch, M. D. Search for Related Content PubMed PubMed Citation Articles by Skoble, J. Articles by Welch, M. D. Pubmed/NCBI databases Substance via MeSH Social Bookmarking                            What's this?

© The Rockefeller University Press, 0021-9525/2000//527 $5.00
The Journal of Cell Biology, Volume 150, Number 3, , 2000 527-538

Three Regions within Acta Promote Arp2/3 Complex-Mediated Actin Nucleation and Listeria monocytogenes Motility

^a Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720-3200
^b School of Public Health, University of California, Berkeley, Berkeley, California 94720-3200
Department of Molecular and Cell Biology, LSA Room 301, University of California, Berkeley, Berkeley, CA 94720-3200.(510) 643-6791(510) 643-9019

welch{at}socrates.berkeley.edu

The Listeria monocytogenes ActA protein induces actin-based motility by enhancing the actin nucleating activity of the host Arp2/3 complex. Using systematic truncation analysis, we identified a 136-residue NH₂-terminal fragment that was fully active in stimulating nucleation in vitro. Further deletion analysis demonstrated that this fragment contains three regions, which are important for nucleation and share functional and/or limited sequence similarity with host WASP family proteins: an acidic stretch, an actin monomer–binding region, and a cofilin homology sequence. To determine the contribution of each region to actin-based motility, we compared the biochemical activities of ActA derivatives with the phenotypes of corresponding mutant bacteria in cells. The acidic stretch functions to increase the efficiency of actin nucleation, the rate and frequency of motility, and the effectiveness of cell–cell spread. The monomer-binding region is required for actin nucleation in vitro, but not for actin polymerization or motility in infected cells, suggesting that redundant mechanisms may exist to recruit monomer in host cytosol. The cofilin homology sequence is critical for stimulating actin nucleation with the Arp2/3 complex in vitro, and is essential for actin polymerization and motility in cells. These data demonstrate that each region contributes to actin-based motility, and that the cofilin homology sequence plays a principal role in activation of the Arp2/3 complex, and is an essential determinant of L. monocytogenes pathogenesis.

Key Words: bacteria • pathogenesis • cell movement • cytoskeleton • microfilament proteins

© 2000 The Rockefeller University Press

CiteULike

Complore

Connotea

Del.icio.us

Digg

Facebook

Reddit

Technorati

Twitter

Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents