Transitions: A unified cellular and in vitro approach to discover molecular mechanisms of microtubule dynamics and regulation

University Of Texas Southwestern Medical Center, Dallas TX

Investigators

Abstract

Through this “Transitions” award, the principal investigator will obtain training in modern genetics and imaging methods and apply these skills to the study of the dynamic cellular polymers called microtubules, which provide structure and shape to eukaryotic cells. The goals of this projects are to discover new, mechanism-defining mutations in the polymerizing subunits and to understand how cellular functions of microtubules respond to selective perturbations of polymerization dynamics. The long-term goal of the work is to create a more wholistic understanding of microtubule dynamics that bridges molecules to phenotypes using a combination of in vitro and in cell studies, unified with mechanism-specific tubulin mutants. The results and materials arising from this work will provide new insights into a fundamental process of high significance. In addition to the impact of the work itself, broader impacts of the project include new training for the PI in scientific animation that will allow dissemination of this increasingly important discipline at the PI’s home institution through a new nanocourse. Graduate and undergraduate students will also receive interdisciplinary training by taking part in the research, and the PI will continue microscopy-based outreach activities at local public schools. The dynamic properties of microtubules are central to their function, and they derive from the structural and biochemical properties of individual αβ-tubulin subunits and their interactions within the polymer. Understanding the molecular mechanisms underlying microtubule dynamics and regulation has been challenging because doing so requires integrating ‘one molecule at a time’ views of biochemistry and structure with lower-resolution measurements of collective behavior spanning different length and time scales. During the professional development phase of the project, the PI will receive training in modern yeast genetics and imaging by performing suppressor and de novo screens to identify new mutations that perturb microtubule dynamics and by defining their consequences for cellular function. The research portion of the project will encompass two complementary directions: (i) using larger scale genetic screening to identify new buried mutations that perturb microtubule dynamics, and (ii) determining the consequences for spindle assembly and chromosome segregation of ‘re-tuning’ cellular microtubule dynamics by expressing variable amounts of mechanism-specific tubulin mutants. These new methods and directions will overcome current bottlenecks and allow the PI to undertake a broader scope of research to connect mechanistic studies to cellular physiology. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.