Abstract
The mitochondrial pathway of apoptosis involves a complex interplay between dozens of proteins and lipids, and is also dependent on the shape and size of mitochondria. The use of cellular models in past studies has not been ideal for investigating how the complex multi-factor interplay regulates the molecular mechanisms of mitochondrial outer membrane permeabilization (MOMP). Isolated systems have proven to be a paradigm to deconstruct MOMP into individual steps and to study the behavior of each subset of MOMP regulators. In particular, isolated mitochondria are key to in vitro studies of the BCL-2 family proteins, a complex family of pro-survival and pro-apoptotic proteins that directly control the mitochondrial pathway of apoptosis (Renault et al., 2013).In this protocol, we describe three complementary procedures for investigating in real-time the effects of MOMP regulators using isolated mitochondria. The first procedure is “Liver mitochondria isolation” in which the liver is dissected from mice to obtain mitochondria. “Mitochondria labeling with JC-1 and size fractionation” is the second procedure that describes a method to label, fractionate by size and standardize subpopulations of mitochondria. Finally, the “Real-time MOMP measurements” protocol allows to follow MOMP in real-time on isolated mitochondria. The aforementioned procedures were used to determine in vitro the role of mitochondrial membrane shape at the level of isolated cells and isolated mitochondria (Renault et al., 2015).
Keywords: Apoptosis, Mitochondria, BCL-2 Family, MOMP, Mitochondrial Fractionation
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Acknowledgments
We would like to thank everyone in the Chipuk Laboratory for their assistance and support. This work was supported by the following: NIH grants CA157740 and CA206005 (to J.E. Chipuk.); a pilot project from NIH P20AA017067 (to J.E. Chipuk), the JJR Foundation (to J.E. Chipuk), the William A. Spivak Fund (to J.E. Chipuk), the Fridolin Charitable Trust (to J.E. Chipuk), and an American Cancer Society Research Scholar Award (to J.E. Chipuk). This work was also supported in part by two research grants (5-FY11-74 and 1-FY13-416) from the March of Dimes Foundation (to J.E. Chipuk), the Leukemia and Lymphoma Scholar Award (to J.E. Chipuk), and the Developmental Research Pilot Project Program within the Department of Oncological Sciences at Mount Sinai (to J.E. Chipuk).
References
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