Context-dependent mechanogating of PIEZO channels

• Applicant: Professor Dr. Stefan Lechner
• Subject Area: Molecular Biology and Physiology of Neurons and Glial Cells
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 430270658

All cells of our organism are exposed to mechanical forces of one kind or another and are thus equipped with sensors that enable them to detect and convert mechanical stimuli into biochemical signals – a process called mechanotransduction. PIEZO1 and PIEZO2 are mechanically-activated ion channels that play an important role in mechanotransduction in a variety of different cell types including e.g. erythrocytes, chondrocytes, bladder urothelial cells and sensory neurons. In the previous funding period, my research focused on the intramolecular force-coupling mechanisms (i.e. domain-domain interactions within the PIEZO2 trimer) that mediate activation of PIEZO2. A recurring observation of my research was that different types of experimental mechanical stimuli such as membrane stretch applied via the patch-pipette in cell-attached recordings and focal mechanical indentation of the cell with a glass rod applied during whole-cell recording, engage different intracellular as well as intramolecular force-coupling mechanisms to activate PIEZO2. This observation raised the question as to whether different types of naturalistic mechanical stimuli also activate PIEZOs via different force-transmission pathways or whether the different pathways act synergistically to activate PIEZOs in fully intact cells. Hence, the overarching goals of this follow-up proposal are (i) to decipher the contribution of different intracellular and intramolecular force-coupling mechanisms to the activation of PIEZOs by different naturalistic stimuli and (ii) to continue my question to understand the intramolecular force-coupling mechanisms underlying PIEZO channel gating. To address the former question, I will examine the force-transmission pathways involved in the detection of traction forces that occur during neurite outgrowth and cell migration – two processes that were shown to be controlled by PIEZO channel. Moreover, I will examine the role of the cytoskeleton in activating PIEZOs in response to whole-cell compression vs. focal mechanical indentation. Finally, to gain novel insights into the intramolecular gating motions of PIEZOs, I will utilize MINFLUX microscopy to examine conformational changes of PIEZOs during channel activation. Together, the proposed experiments will clarify how PIEZO channels are gated in fully intact cells, which will facilitate future research aiming at understanding how cell adapt to mechanical stress in an ever-changing mechanical environment in order to maintain cell, tissue and not least body integrity.

• DFG Programme: Research Grants