Comparative electron microscopic study on projectin and titin binding to F-actin
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Updated: Sep 21, 2026

Using Microfluidics and Fluorescence Microscopy to Study the Assembly Dynamics of Single Actin Filaments and Bundles
Published on: May 5, 2022
Z A Podlubnaya1, M D Shpagina, I M Vikhlyantsev
1Institute of Theoretical and Experimental Biophysics RAS, Pushchino 142290, Moscow Region, Russia. podlubnaya@mail.iteb.ru
Abstract:
Using the system of F-actin paracrystals, we have obtained electron microscopic evidence that projectin from synchronous flight muscles of Locusta migratoria binds to actin filaments in the same fashion as skeletal titin. Control actin paracrystals formed in the presence of Mg(2+) ions have great width and length and blunted ends. The addition of either projectin or titin results in disruption of compact ordered packing of F-actin in paracrystals and leads to the formation of loose filament bundles with smaller diameters and tapered ends. It is also accompanied with the appearance of individual actin filaments in considerable amounts. The effect becomes more pronounced with the increase in concentrations of added projectin or titin. Possible physiological implications of projectin-actin interactions are discussed.
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