Katalin Türmer1, József Orbán2, Pál Gróf3, Miklós Nyitrai4. 1. Department of Biophysics, Medical School, University of Pécs, Szigeti u. 12, Pécs H-7624, Hungary; János Szentágothai Research Center, Pécs H-7624, Hungary. 2. Department of Biophysics, Medical School, University of Pécs, Szigeti u. 12, Pécs H-7624, Hungary; János Szentágothai Research Center, Pécs H-7624, Hungary; MTA-PTE High Intensity Terahertz Research Group, Hungary. 3. Department of Biophysics and Radiation Biology, Semmelweis University of Medicine, IX. Tűzoltó u. 37-47, Budapest H-1095, Hungary. 4. Department of Biophysics, Medical School, University of Pécs, Szigeti u. 12, Pécs H-7624, Hungary; János Szentágothai Research Center, Pécs H-7624, Hungary; MTA-PTE Nuclear-Mitochondrial Interactions Research Group, Hungary. Electronic address: miklos.nyitrai@aok.pte.hu.
Abstract
BACKGROUND: Actin filament bundling proteins mediate numerous processes in cells such as the formation of cell membrane protrusions or cell adhesions and stress fiber based locomotion. Among them alpha-actinin and fascin are the most abundant ones. This work characterizes differences in molecular motions in actin filaments due to the binding of these two actin bundling proteins. METHODS: We investigated how alpha-actinin and fascin binding modify the conformation of actin filaments by using conventional and saturation transfer EPR methods. RESULTS: The result characteristic for motions on the microsecond time scale showed that both actin bundling proteins made the bending and torsional twisting of the actin filaments slower. When nanosecond time scale molecular motions were described the two proteins were found to induce opposite changes in the actin filaments. The binding of one molecule of alpha-actinin or fascin modified the conformation of numerous actin protomers. CONCLUSION: As fascin and alpha-actinin participates in different cellular processes their binding can serve the proper tuning of the structure of actin by establishing the right conformation for the interactions with other actin binding proteins. Our observations are in correlation with the model where actin filaments fulfill their biological functions under the regulation by actin-binding proteins. GENERAL SIGNIFICANCE: Supporting the general model for the cellular regulation of the actin cytoskeleton we showed that two abundant actin bundling proteins, fascin and alpha-actinin, alter the conformation of actin filaments through long range allosteric interactions in two different ways providing the structural framework for the adaptation to specific biological functions.
BACKGROUND: Actin filament bundling proteins mediate numerous processes in cells such as the formation of cell membrane protrusions or cell adhesions and stress fiber based locomotion. Among them alpha-actinin and fascin are the most abundant ones. This work characterizes differences in molecular motions in actin filaments due to the binding of these two actin bundling proteins. METHODS: We investigated how alpha-actinin and fascin binding modify the conformation of actin filaments by using conventional and saturation transfer EPR methods. RESULTS: The result characteristic for motions on the microsecond time scale showed that both actin bundling proteins made the bending and torsional twisting of the actin filaments slower. When nanosecond time scale molecular motions were described the two proteins were found to induce opposite changes in the actin filaments. The binding of one molecule of alpha-actinin or fascin modified the conformation of numerous actin protomers. CONCLUSION: As fascin and alpha-actinin participates in different cellular processes their binding can serve the proper tuning of the structure of actin by establishing the right conformation for the interactions with other actin binding proteins. Our observations are in correlation with the model where actin filaments fulfill their biological functions under the regulation by actin-binding proteins. GENERAL SIGNIFICANCE: Supporting the general model for the cellular regulation of the actin cytoskeleton we showed that two abundant actin bundling proteins, fascin and alpha-actinin, alter the conformation of actin filaments through long range allosteric interactions in two different ways providing the structural framework for the adaptation to specific biological functions.
Authors: Qi Wang; Younghyun Lee; Igor Shuryak; Monica Pujol Canadell; Maria Taveras; Jay R Perrier; Bezalel A Bacon; Matthew A Rodrigues; Richard Kowalski; Christopher Capaccio; David J Brenner; Helen C Turner Journal: Sci Rep Date: 2020-07-29 Impact factor: 4.379
Authors: Younghyun Lee; Monica Pujol Canadell; Igor Shuryak; Jay R Perrier; Maria Taveras; Purvi Patel; Antonius Koller; Lubomir B Smilenov; David J Brenner; Emily I Chen; Helen C Turner Journal: Sci Rep Date: 2018-09-10 Impact factor: 4.379
Authors: Yashar Bashirzadeh; Steven A Redford; Chatipat Lorpaiboon; Alessandro Groaz; Hossein Moghimianavval; Thomas Litschel; Petra Schwille; Glen M Hocky; Aaron R Dinner; Allen P Liu Journal: Commun Biol Date: 2021-09-28