GMF severs actin-Arp2/3 complex branch junctions by a cofilin-like mechanism

Casey A. Ydenberg, Shae B. Padrick, Meredith O. Sweeney, Meghal Gandhi, Olga Sokolova, Bruce L. Goode

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

Background Branched actin filament networks driving cell motility, endocytosis, and intracellular transport are assembled in seconds by the Arp2/3 complex and must be equally rapidly debranched and turned over. One of the only factors known to promote debranching of actin networks is the yeast homolog of glia maturation factor (GMF), which is structurally related to the actin filament-severing protein cofilin. However, the identity of the molecular mechanism underlying debranching and whether this activity extends to mammalian GMF have remained open questions. Results Using scanning mutagenesis and total internal reflection fluorescence microscopy, we show that GMF depends on two separate surfaces for debranching. One is analogous to the G-actin and F-actin binding site on cofilin, but we show using fluorescence anisotropy and chemical crosslinking that it instead interacts with actin-related proteins in the Arp2/3 complex. The other is analogous to a second F-actin binding site on cofilin, which in GMF appears to contact the first actin subunit in the daughter filament. We further show that GMF binds to the Arp2/3 complex with low nanomolar affinity and promotes the open conformation. Finally, we show that this debranching activity and mechanism are conserved for mammalian GMF. Conclusions GMF debranches filaments by a mechanism related to cofilin-mediated severing, but in which GMF has evolved to target molecular junctions between actin-related proteins in the Arp2/3 complex and actin subunits in the daughter filament of the branch. This activity and mechanism are conserved in GMF homologs from evolutionarily distant species.

Original languageEnglish (US)
Pages (from-to)1037-1045
Number of pages9
JournalCurrent Biology
Volume23
Issue number12
DOIs
StatePublished - Jun 17 2013

Fingerprint

Glia Maturation Factor
Actin-Related Protein 2-3 Complex
Actin Depolymerizing Factors
actin
Actins
microfilaments
Actin Cytoskeleton
binding sites
Binding Sites
proteins
endocytosis
Fluorescence Polarization
fluorescence microscopy
crosslinking
Mutagenesis
cell movement
mutagenesis
Endocytosis
Fluorescence microscopy
Fluorescence Microscopy

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)

Cite this

Ydenberg, C. A., Padrick, S. B., Sweeney, M. O., Gandhi, M., Sokolova, O., & Goode, B. L. (2013). GMF severs actin-Arp2/3 complex branch junctions by a cofilin-like mechanism. Current Biology, 23(12), 1037-1045. https://doi.org/10.1016/j.cub.2013.04.058

GMF severs actin-Arp2/3 complex branch junctions by a cofilin-like mechanism. / Ydenberg, Casey A.; Padrick, Shae B.; Sweeney, Meredith O.; Gandhi, Meghal; Sokolova, Olga; Goode, Bruce L.

In: Current Biology, Vol. 23, No. 12, 17.06.2013, p. 1037-1045.

Research output: Contribution to journalArticle

Ydenberg, CA, Padrick, SB, Sweeney, MO, Gandhi, M, Sokolova, O & Goode, BL 2013, 'GMF severs actin-Arp2/3 complex branch junctions by a cofilin-like mechanism', Current Biology, vol. 23, no. 12, pp. 1037-1045. https://doi.org/10.1016/j.cub.2013.04.058
Ydenberg CA, Padrick SB, Sweeney MO, Gandhi M, Sokolova O, Goode BL. GMF severs actin-Arp2/3 complex branch junctions by a cofilin-like mechanism. Current Biology. 2013 Jun 17;23(12):1037-1045. https://doi.org/10.1016/j.cub.2013.04.058
Ydenberg, Casey A. ; Padrick, Shae B. ; Sweeney, Meredith O. ; Gandhi, Meghal ; Sokolova, Olga ; Goode, Bruce L. / GMF severs actin-Arp2/3 complex branch junctions by a cofilin-like mechanism. In: Current Biology. 2013 ; Vol. 23, No. 12. pp. 1037-1045.
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AU - Gandhi, Meghal

AU - Sokolova, Olga

AU - Goode, Bruce L.

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