Death by Light: Using Channelrhodopsin-2 to Induce Mitochondrial Damage and Apoptosis (2012)

Undergraduates: Matt Danzi, Corey Cusack

Faculty Advisor: Mohanish Deshmukh
Department: Biology

---

The aim of this project was to develop a research tool which would allow for direct and precise insult to a cell thereby causing cell death by apoptosis without causing any unwanted side effects. One of the key steps in cell death by apoptosis is the loss of electrical potential across the mitochondrial inner membrane. The light-activated ion channel called Channelrhodopsin-2 (ChR2) has the ability to permit the flow of ions across a membrane when it is activated by shining blue light on it. So for this project, ChR2 was tagged with a red fluorescent protein and targeted to the mitochondrial inner membrane in order to trigger apoptosis via a loss of mitochondrial membrane potential when the ChR2 is activated by blue light. Mitochondrial localization of the ChR2 was checked using immunofluorescence to compare the location of the ChR2 with known mitochondrial markers such as the protein cytochrome c. The result of these experiments shows that some of the ChR2 is localizing to mitochondria but the activation of this ChR2 is insufficient to depolarize the mitochondrial inner membrane and trigger apoptosis. Further experiments will aim to increase the levels of ChR2 expression in the mitochondria so that activation of ChR2 will be able to depolarize the mitochondrial inner membrane and trigger apoptosis.