Mechanical and Civil Engineering Seminar

Mechanical and Civil Engineering Seminar Series

Title: How colloidal physics instantiate life in biological cells

Abstract: We are interested in how physics at the colloidal scale instantiate life in biological cells. While principles from physics have driven recent paradigm shifts in how collective biomolecular behaviors orchestrate life, many mechanistic aspects of e.g. transcription, translation, and condensation remain mysterious because understanding and controlling them requires unifying two disparate physical regimes: the atomistic (structural biology) and the microscopic (systems biology). Colloidal-scale modeling bridges this divide and links molecular-scale behaviors to whole-cell function. Today I will discuss our computational model of a bacterial cell, where we represent biomolecules and their interactions physically and chemically, individually and explicitly. With it, we tackle a fundamental open question in biology, from a physico-chemical perspective: why protein synthesis speeds up during faster E. coli growth. We report a new mechanism, "stoichiometric crowding", that leads to a previously undiscovered increase in ribosome productivity that in turn drives the speedup in protein synthesis. More generally, our computational study of protein synthesis in E. coli from the tandem perspective of cell biology and meso-scale physics presents a unique opportunity to broadly explore how the physical state of the cell impacts biological function – and to uncover links among genetic mutations, stress adaptation, and colloidal-scale physics that regulate cell growth or promote dysregulation and disease pathology. Our future vision of this work is a platform for physics-based therapeutics

Bio: Roseanna N. Zia is an Associate Professor of Chemical Engineering and Otterson Faculty Scholar at Stanford University. She received her Ph.D. from the California Institute of Technology in Mechanical Engineering in 2011 with Professor John F. Brady, for development of theory in colloidal hydrodynamics and microrheology. Zia subsequently conducted post-doctoral study of colloidal gels at Princeton University, in collaboration with Professor William B. Russel. Zia began her faculty career at Cornell in January 2013, then subsequently moved her research group to Stanford University in 2017.

NOTE: With the recent spread of the Omicron variant of SARS-CoV-2 and warnings from public health officials about a winter wave of COVID cases, the Institute will start the winter term with one week of remote instruction. From January 3 through January 7, all courses will be offered via Zoom.

Please click the link below to join the webinar:

https://caltech.zoom.us/j/85335887536?pwd=R09vdGphblFQNDFnUE5ua3JPQkFRZz09

Passcode: 884385