Drebrin-like protein DBN-1 is a sarcomere component that stabilizes actin filaments during muscle contraction
Butkevich, Eugenia ; Bodensiek, Kai ; Fakhri, Nikta ; von Roden, Kerstin ; Schaap, Iwan A. T. ; Majoul, Irina ; Schmidt, Christoph F. ; Klopfenstein, Dieter R.
Citable Link (URL):http://resolver.sub.uni-goettingen.de/purl?gs-1/16945
Actin filament organization and stability in the sarcomeres of muscle cells are critical for force generation. Here we identify and functionally characterize a Caenorhabditis elegans drebrin-like protein DBN-1 as a novel constituent of the muscle contraction machinery. In vitro, DBN-1 exhibits actin filament binding and bundling activity. In vivo, DBN-1 is expressed in body wall muscles of C. elegans. During the muscle contraction cycle, DBN-1 alternates location between myosin- and actin-rich regions of the sarcomere. In contracted muscle, DBN-1 is accumulated at I-bands where it likely regulates proper spacing of α-actinin and tropomyosin and protects actin filaments from the interaction with ADF/cofilin. DBN-1 loss of function results in the partial depolymerization of F-actin during muscle contraction. Taken together, our data show that DBN-1 organizes the muscle contractile apparatus maintaining the spatial relationship between actin-binding proteins such as α-actinin, tropomyosin and ADF/cofilin and possibly strengthening actin filaments by bundling.
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