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Force-Dependent Structural Changes of Filamin C Rod Domains Regulated by Filamin C Dimer.

Yunxin DengJie Yan
Published in: Journal of the American Chemical Society (2023)
Filamin C (FLNC), a large dimeric actin-binding protein in muscle cells, plays a critical role in transmitting force in the cytoskeleton and that between membrane receptors and the cytoskeleton. It performs crucial mechanosensing and downstream mechanotransduction functions via force-dependent interactions with signaling proteins. Mutations in FLNC have been linked to muscle and heart diseases. The mechanical responses of the force-bearing elements in FLNC have not been determined. This study investigated the mechanical responses of FLNC domains and their dimerization interface using magnetic tweezers. Results showed high stability of the N-terminal domains in the rod-1 segment but significant changes in the rod-2 domains in response to forces of a few piconewtons (pN). The dimerization interface, formed by the R24 domain, has a lifetime of seconds to tens of seconds at pN forces, and it dissociates within 1 s at forces greater than 14 pN. The findings suggest the FLNC dimerization interface provides sufficient mechanical stability that enables force-dependent structural changes in rod-2 domains for signaling protein binding and maintains structural integrity of the rod-1 domains.
Keyphrases
  • single molecule
  • binding protein
  • skeletal muscle
  • heart failure
  • induced apoptosis
  • atrial fibrillation
  • cell death
  • oxidative stress
  • transcription factor
  • high resolution