Strain-induced mechanoresponse depends on cell contractility and BAG3-mediated autophagy

Mol Biol Cell. 2021 Oct 1;32(20):ar9. doi: 10.1091/mbc.E21-05-0254. Epub 2021 Aug 11.

Abstract

Basically, all mammalian tissues are constantly exposed to a variety of environmental mechanical signals. Depending on the signal strength, mechanics intervenes in a multitude of cellular processes and is thus capable of inducing simple cellular adaptations but also complex differentiation processes and even apoptosis. The underlying recognition typically depends on mechanosensitive proteins, which most often sense the mechanical signal for the induction of a cellular signaling cascade by changing their protein conformation. However, the fate of mechanosensors after mechanical stress application is still poorly understood, and it remains unclear whether protein degradation pathways affect the mechanosensitivity of cells. Here, we show that cyclic stretch induces autophagosome formation in a time-dependent manner. Formation depends on the cochaperone BAG family molecular chaperone regulator 3 (BAG3) and thus likely involves BAG3-mediated chaperone-assisted selective autophagy. Furthermore, we demonstrate that strain-induced cell reorientation is clearly delayed upon inhibition of autophagy, suggesting a bidirectional cross-talk between mechanotransduction and autophagic degradation. The strength of the observed delay depends on stable adhesion structures and stress fiber formation in a Ras homologue family member A (RhoA)-dependent manner.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Animals
  • Apoptosis / physiology
  • Apoptosis Regulatory Proteins / metabolism*
  • Autophagosomes / metabolism
  • Autophagy / physiology
  • Biomechanical Phenomena
  • Cell Line
  • Fibroblasts / cytology
  • Fibroblasts / metabolism
  • Mechanoreceptors / cytology
  • Mechanoreceptors / metabolism*
  • Mechanotransduction, Cellular
  • Mice
  • Muscle, Smooth / cytology
  • Muscle, Smooth / metabolism
  • Proteolysis
  • Rats
  • Signal Transduction / physiology
  • Transcription Factors / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Apoptosis Regulatory Proteins
  • BAG3 protein, rat
  • Transcription Factors