Imaging ONEWORLD - 'Motion of single molecular tethers reveals dynamic subdomains at organelle contact sites.' - Chris Obara


Scientific Organisers: Stefanie Reichelt, Alex Sossick, Nick Barry, Alessandro Esposito and Kirti Prakash

The meeting will begin at 1pm BST.

As part of the 'Imaging ONEWORLD' series, the focus of these lectures is on microscopy and image analysis methods and how to apply these to your research. Almost all aspects of imaging such as sample preparation, labelling strategies, experimental workflows, ‘how-to’ image and analyse, as well as facilitating collaborations and inspiring new scientific ideas will be covered. Speakers will be available for questions and answers. The organisers, CRUK CI core facility staff, Gurdon Institute, MRC-LMB, MRC Cancer Unit and NPL will be able to continue the discussion and provide advice on your imaging projects.


Speaker

  • Chris Obara

    Janelia Research Campus
    Christopher Obara a postdoctoral fellow working in the group of Jennifer Lippincott-Schwartz at the HHMI Janelia Research Campus. He received his bachelor’s degrees in Physics and Entomology at the University of Florida before performing his doctoral work at the National Institute of Allergy and Infectious Diseases. His dissertation work was focused on quantitative cytometry- and microscopy-based approaches to defining the stoichiometric properties of virus-antibody interactions during productive and abortive virus membrane fusion events. He is broadly interested in the way protein and lipid interactions have evolved to solve complex energetic problems in living systems. His current work focuses on the development and application of novel imaging approaches to characterize the biophysical and material processes that give rise to biological events, with a particular focus in the endomembrane system of mammalian cells.
     


Speaker's Abstract

Membrane-bound organelles provide distinct compartments where incompatible biological processes can be separated from one another. However, biochemical reactions in these disparate environments must be coordinated to facilitate homeostasis, particularly in response to environmental changes. Sites of direct contact between the organelles play an important role in this process, serving as signaling hubs and locations of direct transfer for macromolecules. Numerous specific molecular tethers have been implicated in contact site regulation, but their small size and dynamic nature has made direct visualization of this process challenging. Here, we use high-speed single molecule imaging to directly observe tethering and release dynamics of tethers in individual contact sites between the ER and mitochondria. We demonstrate the existence of structurally-regulated subdomains within single contact sites by comparative imaging with 3D electron microscopy of vitreously-frozen samples. We find that organelle contacts are highly fluid environments, with individual tethers arriving and leaving on a timescale of seconds.