PolarNet at the EMBO Polarity Meeting 2017

Occurring once every two years, the EMBO conference on Cell Polarity and Membrane Dynamics is an excellent conference for young researchers working on the topic to attend. The conference is limited to about 200 participants, giving one the chance to interact with almost everyone and converse as scientists love to do. This year, it took place between the 4th and 9th of June. The stunning location in Sant Feliu de Guixols, Spain, and the wonderful program put together by organisers Dr. Fernando Martin-Belmonte (CBGMSO, Madrid) and Dr. Gillian Griffiths (MRC, Cambridge) made the event an absolute pleasure to attend!

Students and group leaders from PolarNet who attended the conference

Beautiful views of the ocean in Sant Feliu de Guixols

The conference was divided up into several sessions:

  1. Mechanobiology and mathematical models
  2. Planar Polarity
  3. Epithelial polarity in development and regeneration
  4. Polarized trafficking, sorting and secretion
  5. Stem Cells and Cancer
  6. Polarity in the immune response
  7. Endocytic pathways in polarity

Each session featured some invited speakers and short talks, with several familiar names from the world of polarity research presenting both published and unpublished data.

The keynote lecture was given by Dr. Marino Zerial (CBG, Dresden) on “Hepatocyte polarity and the organization of the liver”. Hepatocytes exhibit a complex apico-basal polarity: their apical membranes form a three-dimensional narrow belt between adjacent cells, which collectively give rise to the bile canaliculi (BC) network, an essential component for bile secretion and overall liver function. The project from the Zerial lab, focused on using high resolution imaging techniques to build a 3D reconstruction of the bile canaliculi network in order to develop a multi-scale predictive mathematical model. The work so far, hints at a long-range order of hepatocyte polarity in the central-portal vein orientation where hepatocytes are wrapped in sinusoidal cages.

Liver tissue organization and function. Left: Schematic from Alberts, et al., 2014. The Molecular Biology of the Cell. Right: 3D reconstruction of liver tissue from the Zerial lab webpage

Since my PhD project deals with single molecule techniques and polarity complexes, I thought to focus a little more about two talks that greatly interested me during the conference.

Dr. Oriol Gallego gave a short talk about his recently published data on the structure of the exocyst complex (Picco et al., 2017, Cell). The complex itself is conserved in all eukaryotes and contains eight subunits. So far, we were limited to understanding about 26% of the structure of the exocyst from crystallography techniques. In this study, the authors used engineered yeast to induce the anchoring of the exocyst to static platforms. This anchoring platform was tagged with one fluorophore to act as a reference point, while a fluorophore of a different colour was used to tag the terminus of each of the subunits (one at a time). Using high resolution single molecule imaging, it was possible to measure the distance between the two fluorophores and use a computer model to position the subunits in 3D space. This study not only provided an in depth look at the architecture of the exocyst complex, but also suggested how several exocyst complexes could cooperate during vesicle tethering.

Graphical abstract from Picco et al., 2017 (Cell) on the discovery of the structure of the exocyst

Dr. Daniel St. Johnston (Gurdon Institute, Cambridge) gave an interesting talk on unpublished research on the Drosophila midgut epithelium as a novel model system that was more comparable to mammalian epithelia, due to its septate junctions being above the adherens junctions. He focused on the possibility of alternative modes of polarity maintenance, as knocking out several components of traditional polarity pathways seemed to have no visible phenotype. He then went on to discuss more on the lateral junctional components: Discs Large (DLG), Lethal Giant Larvae (LGL) and Scribbled.

Just to mention a few other speakers: Dr. Matthieu Piel (Institut Curie) gave an entertaining talk on controlled cell deformation in aiding cell migration and nuclear damage that occurs in the process, Dr. Suzanne Eaton (CBG, Dresden) spoke on mechanical tension regulating the endocytosis mediated turnover of E-cadherin in the Drosophila wing disc, and Dr. Ian Macara (Vanderbilt University, Nahsville) spoke on an alternative function of PAR-3, which is considered a classical polarity protein, in acting also as an exocyst receptor in mammalian epithelia.

Research from the labs of PolarNet were also featured: Dr. Mike Boxem, Dr. Anne Spang and Dr. Fluorent Peglion (Goehring Lab), all gave talks ranging from RNA based polarity, to the proteins involved in traditional polarity complexes.

At the end of each day, a poster session took place, where the participants mingled, Sangria in hand, discussing new ideas late into the night. All in all, it was a great event for the Early Stage Researchers of PolarNet, to be at.