Cracking the tubulin code of cell migration - Project summary Directional cell migration is crucial for many physiological processes, including angiogenesis, wound healing, tissue remodeling, and immune responses. Dysregulated cell migration is associated with various diseases, such as fibrosis and metastatic cancer. Understanding the molecular mechanisms underlying cell migration has broad implications for human health. Cells employ different modes of migration—collective, mesenchymal, amoeboid, etc.—depending on their intracellular state and extracellular environment. Regardless of the mode, cell migration fundamentally requires coordination of cytoskeletal components (e.g., actin, microtubules, intermediate filaments), extracellular environment sensing, and the generation of physical forces for locomotion. Previous studies have highlighted the critical role of microtubules in various aspects of cell migration. While microtubules undergo several post-translational modifications, how these modifications influence cell migration remains largely unexplored. Microtubule acetylation (acetylation of Lysine-40 on α- tubulin) and detyrosination (removal of the carboxy-terminal tyrosine residue on α-tubulin) have been implicated in metastatic cancer, underscoring the need for a mechanistic understanding of their effects on cell migration and cytoskeletal dynamics. However, elucidating these molecular pathways is technically challenging due to the lack of tools to acutely and specifically manipulate these modifications in living cells. To address this gap, I have developed genetically encoded, light-inducible molecular actuators—optoTAT and optoVASH—to specifically and reversibly induce microtubule acetylation and detyrosination, respectively, in living cells. Over the next five years, we will employ these optogenetic tools alongside genetic and pharmacological perturbations to investigate several critical, yet currently intractable, questions: (1) What are the effects of microtubule acetylation and detyrosination on actin and vimentin dynamics, and what molecular signaling pathways mediate these cytoskeletal interactions? (2) How do microtubule acetylation and detyrosination influence cell contractility, mechanosensing, and engagement with the extracellular matrix? (3) What are the effects of these modifications on the mode of migration in two-dimensional environments (flat surfaces) and three-dimensional matrices? Results from this study will illuminate an underexplored area of cytoskeletal biology—microtubule post-translational modifications—and identify key factors that could serve as diagnostic markers or therapeutic targets.
