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Frederick Sachs

Center for Single Molecule Biophysics Physiology and Biophysical Sciences, SUNY, Buffalo, NY

Friday, September 30th, 2016 at 11:00:00 AM

Aula Querzoli - LENS

Published on-line at 12:41:28 PM on Thursday, September 22nd, 2016

Tracing cells by their mechanics

Cells live by the flow of energy among three pools of free energy: chemical, electrical and mechanical.

Cells live by the flow of energy among three pools of free energy:chemical, electrical and mechanical. The chemical pool is studied with biochemical tools, the electrical pool by electrophysiology, and the mechanical pool is generally ignored. Attempting to understand cells without paying attention to mechanics is a bit like building a Ferrari given the periodic table; there are no missing parts, but… 


·         We have learned about molecular mechanics from in vitro tools such as AFM and laser traps, but a dish of saline is not the same as the inside of a living cell. Reductionism can be misleading as we deal with complex systems. We want to know what is going on inside living cells.  To address these issues we designed genetically coded optical probes to measure the stress in specific structural proteins. The force probes are nontoxic since we have made transgenic flies and worms and cell lines. We have learned that:


·         Structural proteins are generally under tension. This allows them to transmit signals across and between cells at speeds much higher than chemical messengers. Touching one part of a cell can lead to changes of stress throughout the cell.

·         There are gradients of stress in specific proteins within single cells, so that affiliated biochemistry will vary from place to place, and over time, even in a single cell.

·         Neighboring cells can have very different distributions of stress.

·         Osmotic stress is not confined to the cell membrane, but is distributed throughout the cytoplasm.

·         Stemness is associated with high stress in actin and α-actinin, and perhaps other proteins.

·         Effector transducers of mechanical stress, such as mechanosensitive ion channels, are modulated by stress in the cytoskeleton.

·         Key observation:We have MUCH MORE TO LEARN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

For further informations, please contact Marco Capitanio.