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Microscopic evidence that actin-interacting protein 1 actively disassembles actin-depolymerizing factor/Cofilin-bound actin filaments.

Shoichiro Ono·Kurato Mohri·Kanako Ono
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Abstract

Actin-depolymerizing factor (ADF)/cofilin and gelsolin are the two major factors to enhance actin filament disassembly. Actin-interacting protein 1 (AIP1) enhances fragmentation of ADF/cofilin-bound filaments and caps the barbed ends. However, the mechanism by which AIP1 disassembles ADF/cofilin-bound filaments is not clearly understood. Here, we directly observed the effects of these proteins on filamentous actin by fluorescence microscopy and gained novel insight into the function of ADF/cofilin and AIP1. ADF/cofilin severed filaments and AIP1 strongly enhanced disassembly at nanomolar concentrations. However, gelsolin, gelsolin-actin complex, or cytochalasin D did not enhance disassembly by ADF/cofilin, suggesting that the strong activity of AIP1 cannot be explained by simple barbed end capping. Barbed end capping by ADF/cofilin and AIP1 was weak and allowed filament elongation, whereas gelsolin or gelsolin-actin complex strongly capped and inhibited elongation. These results suggest that AIP has an active role in filament severing or depolymerization and that ADF/cofilin and AIP1 are distinct from gelsolin in modulating filament elongation.

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Actin CytoskeletonActin Depolymerizing FactorsActinsAnimalsCaenorhabditis elegans ProteinsDestrinGelsolinMicrofilament ProteinsRabbitsComparative StudyJournal ArticleResearch Support, U.S. Gov't, Non-P.H.S.Research Support, U.S. Gov't, P.H.S.

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Shoichiro Ono, Kurato Mohri, Kanako Ono. 2004-01-23. Microscopic evidence that actin-interacting protein 1 actively disassembles actin-depolymerizing factor/Cofilin-bound actin filaments.. https://doi.org/10.1074/jbc.m313418200

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