Tubulin Post-Translational Modifications are altered by changes in Actin-Myosin Contractility in non-muscle cells

All cells regulate their contractility by the interaction of actin and myosin. In non-muscle cells, however, this interaction is regulated by rho, a GTPase, which is the upstream effector for multiple pathways. Cell contractility increases when rho is active, and prior research has shown the depolymerization of microtubules (MTs) activates rho. Microtubules play a role in many cellular functions and it is thought that either associations with MT-associated proteins and/or post-translational modifications to tubulin regulate MT functions. Numerous post-translational modifications (PTMs) to microtubules have been identified, but their roles are not well understood. A possible relationship between changes in cell contractility and two tubulin post-translational modifications, acetylation and detyrosination, has been suggested by past research. We investigated if altered cell contractility caused changes in MT acetylation and detyrosination. We found that inhibition of rho caused a decrease in the amount of acetylation while activation of rho caused an increase. Since MT acetylation and detyrosination correlate with more stable MTs, our results suggest that a signaling pathway or feedback mechanisms exists in cells that allow them to respond to changes in contractility by altering MT dynamics. This not only sheds light on the crosstalk between actin and microtubules due to rho having a feedback mechanism as opposed to linear, but also allows for the speculation that one of the downstream effects of rho is the regulation of the enzymes that control MT acetylation