help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Biophys. J. BioFAST: First Published August 11, 2006. doi:10.1529/biophysj.106.080937
© 2006 by the Biophysical Society.

A more recent version of this article appeared on November 1, 2006.
This Article
Right arrow Full Text (Rapid PDF)
Right arrow All Versions of this Article:
biophysj.106.080937v1
91/9/3519    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Mahaffy, R. E.
Right arrow Articles by Pollard, T. D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mahaffy, R. E.
Right arrow Articles by Pollard, T. D.

CELL BIOPHYSICS

Kinetics of the formation and dissociation of actin filament branches mediated by Arp2/3 complex

Rachel E. Mahaffy 1 and Thomas D. Pollard 1*

1 Yale University

* To whom correspondence should be addressed. E-mail: thomas.pollard{at}yale.edu.

Submitted on January 6, 2006
Revised on March 14, 2006
Accepted on 28 July 2006


  Abstract
The actin filament network at the leading edge of motile cells relies on localized branching by Arp2/3 complex from "mother" filaments growing near the plasma membrane. The nucleotide bound to the mother filaments (ATP, ADP and phosphate or ADP) may influence the branch dynamics. To determine the effect of the nucleotide bound to the subunits of the mother filament on the formation and stability of branches, we compared the time courses of actin polymerization in bulk samples measured using the fluorescence of pyrene actin with observations of single filaments by total internal reflection fluorescence (TIRF) microscopy. While the branch nucleation rate in bulk samples was nearly the same regardless of the nucleotide on the mother filaments, we observed fewer branches by microscopy on ADP bound filaments than on ADP-Pi bound filaments. Observation of branches in the microscope depends on their binding to the slide. Since the probability that a branch binds to the slide is directly related to its lifetime, we used counts of branches to infer their rates of dissociation from mother filaments. We conclude that the nucleotide on the mother filament does not affect the initial branching event, but that branches are an order of magnitude more stable on the sides of new ATP- or ADP-Pi filaments than on ADP- actin filaments.

Key Words: Actin, Arp2/3 complex, branch dynamics




This article has been cited by other articles:


Home page
 Biophys. JHome page
F. J. Brooks and A. E. Carlsson
Actin Polymerization Overshoots and ATP Hydrolysis as Assayed by Pyrene Fluorescence
Biophys. J., August 1, 2008; 95(3): 1050 - 1062.
[Abstract] [Full Text] [PDF]

Home page
 ScienceHome page
D. Chereau, M. Boczkowska, A. Skwarek-Maruszewska, I. Fujiwara, D. B. Hayes, G. Rebowski, P. Lappalainen, T. D. Pollard, and R. Dominguez
Leiomodin Is an Actin Filament Nucleator in Muscle Cells
Science, April 11, 2008; 320(5873): 239 - 243.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
L. Pasic, T. Kotova, and D. A. Schafer
Ena/VASP Proteins Capture Actin Filament Barbed Ends
J. Biol. Chem., April 11, 2008; 283(15): 9814 - 9819.
[Abstract] [Full Text] [PDF]

Home page
 J. Cell Biol.Home page
I. Rouiller, X.-P. Xu, K. J. Amann, C. Egile, S. Nickell, D. Nicastro, R. Li, T. D. Pollard, N. Volkmann, and D. Hanein
The structural basis of actin filament branching by the Arp2/3 complex
J. Cell Biol., March 5, 2008; 180(5): 887 - 895.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Copyright © 2006 by the Biophysical Society.