Confinement Sensing and Signal Optimization via Piezo1/PKA and Myosin II Pathways.

Area of Science:

• Cell biology
• Biophysics
• Mechanobiology

Background:

• Cells utilize specific signaling pathways for locomotion in diverse physical microenvironments.
• The mechanisms by which cells sense and respond to physical confinement remain largely unknown.

Purpose of the Study:

• To elucidate the signaling pathways cells employ to sense and adapt to physical confinement.
• To identify the molecular players involved in confinement-induced cellular responses.

Main Methods:

• Utilized microfabricated devices and substrate-printing techniques.
• Employed Förster resonance energy transfer (FRET)-based biosensors to monitor intracellular signaling.
• Investigated the roles of Piezo1, myosin II, calcium (Ca2+), and protein kinase A (PKA) activity.

Main Results:

• Cellular transition from unconfined to confined spaces increased intracellular Ca2+ levels.
• Ca2+ elevation was dependent on the stretch-activated cation channel Piezo1.
• Confinement led to phosphodiesterase 1 (PDE1)-dependent suppression of PKA activity.
• Both Piezo1 and myosin II independently mediated confinement sensing, as indicated by abrogated differential regulation of PKA and cell stiffness upon their dual inhibition.
• Confinement-activated signals from Piezo1 and myosin II converge on a signaling circuit that optimizes cell motility.

Conclusions:

• Physical confinement triggers a signaling cascade involving Piezo1 and myosin II.
• This cascade modulates intracellular Ca2+ and PKA activity, leading to changes in cell stiffness and motility.
• The study reveals a novel mechanism for cellular adaptation to physical microenvironmental cues.