DATE: May 28, 2020
TIME: 8AM PT, 11AM ET, 4PM GMT, 5PM CET
Mitochondria have traditionally been viewed as energy-generating organelles, through oxidation of metabolic substrates and creation of a proton gradient across the inner mitochondrial membrane (IMM), that is utilized to generate ATP. However, it is increasingly clear that mitochondria communicate frequently with the rest of the cell and are therefore important signaling organelles. Mitochondria are extremely dynamic organelles; that fuse and divide continuously. Failures in mitochondrial dynamics cause severe disorders, and therefore the study of such mechanisms has significant importance.
A growing number of studies suggests that actin polymerization participates in mitochondrial communication and dynamics in mammalian cells. We find that there are at least two distinct modes by which actin and mitochondria interact.
In one mode (Chakrabarti et al (2019) J. Cell Biol. 217(1): 251-268), elevation of cytosolic calcium activates the endoplasmic reticulum (ER)-bound formin INF2, and the resulting actin polymerization stimulates two distinct events that promote mitochondrial division: increased transfer of calcium from ER to mitochondria, (resulting in IMM constriction); and Drp1 recruitment to the outer mitochondrial membrane (OMM), resulting in OMM constriction.
In the other mode (Fung et al (2019) J. Cell Sci.), mitochondrial depolarization causes rapid accumulation of an extensive ‘shell’ of actin filaments around the depolarized mitochondria, dependent on Arp2/3 complex but independent of INF2. This actin shell selectively and subtly unwraps the ER from mitochondria and delays the initial phases of the Pink/Parkin dependent mitophagy pathway.
To achieve the mechanistic information on actin’s role in mitochondrial homeostasis, we have used ANDOR Dragonfly ultra-fast imaging system. Dragonfly provides the perfect solution for imaging live or fixed mitochondria.
In this webinar, we will present our recent results about on the role of actin cytoskeletal on mitochondrial dynamics. Mitochondria imaging analysis tools will also be discussed.
1) Discover the role of ER in regulation mitochondrial dynamics
2) Uncover the role of actin cytoskeleton in stimulating dynamics of both mitochondrial membranes
3) Identify the difficulties in imaging live mitochondria
4) Understand strategies for image live mitochondria
5) Acquire knowledge on biological imaging analysis.