Mechanobiology: how mechanics regulate life

Selected questions:

1. How did the authors determine which regions of PIEZO1 are most responsive to mechanical changes?
2. Does the blades graded flexibility influence the sensibility to mechanical constraints?
3. In Figure 1a, one third of the blade in PIEZO1 could not be resolved using Cryo- EM. What are the reasons for this, and how did the researchers overcome these limitations to model the complete protein structure?
4. How might changes in the lipid composition of the plasma membrane influence the mechanosensitivity and flexibility of PIEZO1?
5. What are the advantages of using nanoscopic fluorescence imaging (iPALM and MINFLUX) to observe PIEZO1 conformations compared to other methods like cryo-EM?
6. How did the researchers ensure that tagging PIEZO1 with fluorophores did not interfere with its native functionality or activation mechanisms?
7. How do small-molecule modulators like Yoda1 and GsMTx-4 influence PIEZO1 activation, and what insights does this provide about the gating mechanism of the channel?
8. Could you explain why the models used to predict the characteristics of PIEZO1 protein (AlphaFold II and PIEZO2 cryo-EM) seems to underestimate the real values, as shown in several figures (Figure 1.e, 2.e, 2.f, 2.g, ...) ? Where does this difference come from ?
9. What does the inter-PIEZO repeat binding energy represent ? How is it calculated and could you explain why there is a significant decrease of free energy between the distal and proximal repeat domains of PIEZO1 blades ?
10. The study observes flexibility differences between the proximal and distal regions of PIEZO1 blades, with greater flexibility in distal regions. How might this graded flexibility influence cooperative vs. independent movement of blade sections, particularly in cells experiencing simultaneous mechanical cues from multiple directions, as in vascular or neuronal cells? Could these interactions create distinct mechanosensory responses unique to such cell types?