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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.