Deciphering the glutamylome to unveil cell mechanics – Mechano-Glu

Cells are continuously challenged by their external mechanical environment. To maintain their homeostasis cells dynamically refine their mechanical properties. Yet, modulating cell mechanics is energy-requiring. Therefore, cells rewire their metabolism to adjust their metabolic needs to their mechanically constraint environment. Together, these findings link mechanical stimuli and metabolic changes and define the mechano-metabo axis as a molecular driver of tissue architecture. Recently, we have demonstrated that mechano-induced glutamine catabolism promotes microtubule glutamylation thereby fine-tuning cells mechanics. Yet, glutamylation is not restricted to tubulin, and mechanisms allowing cells to fine-tune their mechanical state remain largely unknown. Our preliminary data, indicated that several proteins involved in cell metabolism are glutamylated in response to matrix stiffening. Among these proteins, we identified several proteins related to glutamine metabolism. Therefore, we hypothesize that mechanodependent glutamylation of proteins related to glutamine metabolism will fine-tune their function/localization/activity, thus tightly controlling protein glutamylation thereby allowing cells to adapt to their mechanically constrained environment. To elucidate the role of protein glutamylation in the mechanical control of cells we propose a transdisciplinary project that relies on three major conceptual and technical advances present in our laboratories: 1) the demonstration by Partner 1 (P1) that mechanical forces rewire cell metabolism; 2) the demonstration by P2 that glutamylation fine-tune protein function/localization/activity; 3) the unique expertise of P3 in proteomics approaches allowing identification of glutamylation. Specifically, we aim to determine how matrix stiffness modulates proteins glutamylation (Aim 1), and whether and how proteins glutamylation alters the mechano-metabo axis (Aim 2)