Berlin 2015 – scientific programme
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BP: Fachverband Biologische Physik
BP 22: Posters: Cytoskeletal filaments
BP 22.8: Poster
Tuesday, March 17, 2015, 14:00–16:00, Poster A
Drebrin-like protein (DBN-1) is a novel sarcomere component which stabilizes actin filaments during muscle contraction — Eugenia Butkevich1, Kai Bodensiek1, Nikta Fakhri1, Kerstin von Roden1, Iwan T. Schaap1, 2, Irina Majoul3, Christoph F. Schmidt1, and •Dieter R. Klopfenstein1 — 1Drittes Physikalisches Institut, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen — 2Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen — 3Institute of Biology, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck - Germany
Actin filament organization and stability in the sarcomeres of muscle cells are critical for force generation. Here, we have identified and functionally characterized a C. elegans drebrin-like protein DBN-1 as a crucial constituent of the muscle-contraction machinery in the nematode. In vitro, DBN-1 exhibited actin filament binding and bundling activity. High-resolution AFM showed single DBN-1 molecules decorating the sides of actin filaments. In vivo, DBN-1 is expressed in body wall muscles constituting an essential sarcomere component. Surprisingly, during muscle contraction, DBN-1 alternated location between myosin- and actin-rich regions of the myofilament lattice likely regulating proper spacing of alpha-actinin and tropomyosin. A loss-of-function mutation in dbn-1 resulted in the partial depolymerization of F-actin upon muscle contraction. Taken together, DBN-1 organizes the muscle contractile apparatus maintaining the spatial relationship between actin-binding proteins and strengthening actin filaments by bundling.