Competition between myosin II and β<sub>H</sub>-spectrin regulates cytoskeletal tension.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37367948.
- Also identified by DOI 10.7554/eLife.84918 and PMC identifier 10328500.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Spectrins are membrane cytoskeletal proteins generally thought to function as heterotetramers comprising two α-spectrins and two β-spectrins. They influence cell shape and Hippo signaling, but the mechanism by which they influence Hippo signaling has remained unclear. We have investigated the role and regulation of the <i>Drosophila</i> β-heavy spectrin (β<sub>H</sub>-spectrin, encoded by the <i>karst</i> gene) in wing imaginal discs. Our results establish that β<sub>H</sub>-spectrin regulates Hippo signaling through the Jub biomechanical pathway due to its influence on cytoskeletal tension. While we find that α-spectrin also regulates Hippo signaling through Jub, unexpectedly, we find that β<sub>H</sub>-spectrin localizes and functions independently of α-spectrin. Instead, β<sub>H</sub>-spectrin co-localizes with and reciprocally regulates and is regulated by myosin. <i>In vivo</i> and <i>in vitro</i> experiments support a model in which β<sub>H</sub>-spectrin and myosin directly compete for binding to apical F-actin. This competition can explain the influence of β<sub>H</sub>-spectrin on cytoskeletal tension and myosin accumulation. It also provides new insight into how β<sub>H</sub>-spectrin participates in ratcheting mechanisms associated with cell shape change.
Medical subject headings
- Drosophila Proteins
- Spectrin