The F-BAR protein Hof1 tunes formin activity to sculpt actin cables during polarized growth
| Autor: | Brian R. Graziano, Casey A. Ydenberg, Julian A. Eskin, Bruce L. Goode, Salvatore L. Alioto, Mikael V. Garabedian, David P. Waterman, Hoi-Ying E. Yu |
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| Rok vydání: | 2014 |
| Předmět: |
Saccharomyces cerevisiae Proteins
Arp2/3 complex Saccharomyces cerevisiae macromolecular substances Profilins Actin remodeling of neurons Actin-binding protein Molecular Biology Cytoskeleton Cell Proliferation Cell Size Actin nucleation biology fungi Cell Polarity Actin remodeling Articles Cell Biology Actin cytoskeleton Actins Cell biology Actin Cytoskeleton Cytoskeletal Proteins Phenotype Microscopy Fluorescence Formins Mutation biology.protein MDia1 Microtubule-Associated Proteins |
| Zdroj: | Molecular Biology of the Cell |
| ISSN: | 1939-4586 1059-1524 |
| Popis: | A new in vivo role is defined for the yeast F-BAR protein Hof1 in polarized cell growth. Hof1 dimers bind to the FH1 domains of the formin Bnr1 and inhibit actin polymerization while the formin remains attached to filament ends. This activity is required in vivo for normal actin cable architecture and polarized secretion. Asymmetric cell growth and division rely on polarized actin cytoskeleton remodeling events, the regulation of which is poorly understood. In budding yeast, formins stimulate the assembly of an organized network of actin cables that direct polarized secretion. Here we show that the Fer/Cip4 homology–Bin amphiphysin Rvs protein Hof1, which has known roles in cytokinesis, also functions during polarized growth by directly controlling the activities of the formin Bnr1. A mutant lacking the C-terminal half of Hof1 displays misoriented and architecturally altered cables, along with impaired secretory vesicle traffic. In vitro, Hof1 inhibits the actin nucleation and elongation activities of Bnr1 without displacing the formin from filament ends. These effects depend on the Src homology 3 domain of Hof1, the formin homology 1 (FH1) domain of Bnr1, and Hof1 dimerization, suggesting a mechanism by which Hof1 “restrains” the otherwise flexible FH1-FH2 apparatus. In vivo, loss of inhibition does not alter actin levels in cables but, instead, cable shape and functionality. Thus Hof1 tunes formins to sculpt the actin cable network. |
| Databáze: | OpenAIRE |
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