Biochemistry Seminar: Thomas Boothby
Throughout the academic year, the Department of Biochemistry invites professors from other universities and institutes to speak at the University of Colorado Boulder. These seminars provide an opportunity for faculty and students to learn about exciting current research at other universities.
Come out and meet Dr. Thomas Boothby during his seminar.
Dr. Boothby serves as a postdoctoral research fellow at the University of North Carolina at Chapel Hill..
This Seminar is hosted by the Department of Biochemistry. For more information about the seminar or Dr.Boothby's schedule, please email Dr. Roy Parker.
Seminar Title: "Drying without dying: tardigrades use intrinsically disordered proteins to survive extreme dessication."
Tardigrades (AKA water bears) are a phylum of microscopic animals renowned for their ability to survive a number of different environmental extremes including: desiccation, freezing, temperatures above the boiling point of water, intense radiation, low oxygen conditions, and even prolonged exposure to the vacuum of outer space. How tardigrades protect themselves, their cells, and their cellular components from these extremes is largely unknown. To identify candidate mediators of desiccation tolerance we compared transcriptomes from hydrated and drying tardigrades. We found that members of a family of genes encoding intrinsically disordered proteins (IDPs) are heavily upregulated upon desiccation. These IDPs are unique to tardigrades, are required for the tardigrades to survive drying, improve the desiccation tolerance of heterologous systems, and protect enzymes from desiccation in vitro. We found that at a critical concentration these IDPs form gels, and at concentrations where gelation occurs these IDPs stabilize other proteins. A combination of empirical and computational experiments suggests that the tardigrade IDPs, while disordered, exist in a conformational ensemble that resembles a dumbbell - with two collapsed regions bridged by a more extended linker. Our data indicate that the dumbbell-like conformation of these IDPs is essential for their polymerization, and is likely mediated via interprotein beta-beta interactions between termini of different IDPs. As these gels dry, due to their disordered nature, they do not form crystalline solids, but rather form more amorphous, vitrified (glass-like), solids. This phenomenon of vitrification is observed in tardigrades, with purified tardigrade IDPs, and in yeast heterologously expressing the tardigrade IDPs. Experimental disruption of vitrification of these IDPs correlates with a loss of their protective capabilities. We propose that as tardigrades dry they upregulate the expression of their IDPs, resulting in increased cytoplasmic concentrations and polymerization of these proteins, and ultimately in the gelation of the cytoplasm. Furthermore, we speculate that non-desiccation tolerant proteins are encapsulated within the pores of this gel, which prevents them from unfolding and forming nonfunctional aggregates. Then, upon complete desiccation, these gels vitrify, locking the cytoplasmic contents within a protective glass. Rehydration readily returns the tardigrade IDPs to solution, releasing the protected, non-desiccation tolerant proteins.
Monday, January 28 at 2:00pm to 3:00pm
Jennie Smoly Caruthers Biotec Building, Butcher Auditorium
3415 Colorado Avenue, Boulder, CO 80309