Profilin’s affinity for formin regulates the availability of filament ends for actin monomer binding
| Autor: | Naomi Courtemanche, Mark E. Zweifel |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Saccharomyces cerevisiae Proteins
Formins macromolecular substances Saccharomyces cerevisiae Article Protein filament 03 medical and health sciences Profilins 0302 clinical medicine Protein Domains Structural Biology Cytoskeleton Molecular Biology Actin 030304 developmental biology 0303 health sciences Binding Sites biology Chemistry Actin monomer binding fungi Microfilament Proteins Signal transducing adaptor protein Actins Protein Structure Tertiary Actin Cytoskeleton Profilin Microscopy Fluorescence biology.protein Biophysics Profilin binding Peptides 030217 neurology & neurosurgery Protein Binding |
| Zdroj: | J Mol Biol |
| Popis: | Nucleation-promoting proteins tightly regulate actin polymerization in cells. Whereas many of these proteins bind actin monomers directly, formins use the actin-binding protein profilin to dynamically load actin monomers onto their flexible Formin Homology 1 (FH1) domains. Following binding, FH1 domains deliver profilin-actin complexes to filament ends. To investigate profilin’s role as an adaptor protein in formin-mediated elongation, we engineered a chimeric formin that binds actin monomers directly via covalent attachment of profilin to its binding site in the formin. This formin mediates slow filament elongation owing to a high probability of profilin binding at filament ends. Varying the position at which profilin is tethered to the formin alters the elongation rate by modulating profilin occupancy at the filament end. By regulating the availability of the barbed end, we propose that profilin binding establishes a secondary point of control over the rate of filament elongation mediated by formins. Profilin’s differential affinities for actin monomers, barbed ends and polyproline are thus tuned to adaptively bridge actin and formins and optimize the rate of actin polymerization. |
| Databáze: | OpenAIRE |
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