Biophysical Society Thematic Meeting - June 28-July 1, 2015

New Biological Frontiers Illuminated by Molecular Sensors and Actuators

Monday Speaker Abstracts

Optogenetic Investigation of Organelle Quality Control Wei Yuan Yang . Academia Sinica, Taipei, Taiwan.

Autophagy is a trafficking process that enables eukaryotic cells to transport cytoplasmic materials into lysosomes for recycling and degradation, and one of its prominent functions is the selective elimination of dysfunctional organelles. This allows cells to rid themselves of unwanted stress to maintain health and avoid the activation of cell death. One vivid example of this is Parkin-mediated mitophagy: mitochondria defective in protein import results in their selective elimination through the autophagic machinery. The lack of proper mitophagy has been implicated as one cause of Parkinson’s disease. Autophagy is therefore a vital strategy for cellular quality control of organelles. Here I will discuss the prospect of utilizing organelle- specific photosensitizers to probe these processes inside living cells.

All-optical Electrophysiology with Microbial Rhodopsins Adam Cohen . Harvard, Cambridge, USA.

In the wild, microbial rhodopsin proteins convert sunlight into biochemical signals in their host organisms. Some microbial rhodopsins convert sunlight into changes in membrane voltage. We engineered a microbial rhodopsin to run in reverse: to convert changes in membrane voltage into fluorescence signals that are readily detected in a microscope. Archaerhodopsin-derived voltage- indicating proteins enable optical mapping of bioelectric phenomena with unprecedented speed and sensitivity. We are engineering new molecular logic into microbial rhodopsins by taking advantage of their strong optical nonlinearities. For instance, we engineered a bistable rhodopsin into a light-gated voltage integrator which converts a transient electrical impulse into a stable photochemical product.

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