Biophysical Society Thematic Meeting| Padova 2019

Quantitative Aspects of Membrane Fusion and Fission

Friday Speaker Abstracts

MITOCHONDRIAL MEMBRANE DYNAMICS VERSUS STEADY COMPARTMENTALIZATION: A CONTRADICTION? WHAT SUPERRESOLUTION IMAGING CAN TELL US Karin B. Busch 1,2 ; Verena Wilkens 2 ; Timo Appelhans 1,2 ; 1 WWU Münster, Biology, Münster, Nordrhein-Westfalen, Germany 2 University of Osnabrück, Biology and Chemistry, Osnabrück, Niedersachsen, Germany The interplay between mitochondrial dynamics and ultrastructure guarantees mitochondrial functionality and adaptation. How this is regulated and how responsiveness is realized is still little understood. The sub-compartmentalization of the inner membrane in cristae provides numerous distinct bioenergetic compartments but at the same time restricts the diffusion and exchange of membrane proteins as well as their assembly. Another important aspect linked to this problem is the execution of quality control: does is occur locally or mitochondria-wide? In order to understand how regulation, adaptation and quality control are realized we need to know the impact of mitochondrial fusion and fission on the distribution and localization of proteins, and the impact of the specific ultrastructure on lateral protein dynamics. By using single molecule localization and tracking microscopy, multi-color superresolution imaging and Immuno-EM, we found that mitochondria, even after several fusion and fission cycles, have a hybrid character in terms of composition– or else phrased: cristae are rather conservative. We will show that this is correlated with zones of different activity. Single mitochondria are therefore not singular units but small mosaics.

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