background_1 background_2

MEETING REPORT - EMBO Workshop Endoplasmic reticulum: The master regulator of membrane trafficking 23/10/2022 – 27/10/2022 by Lucie Maisonneuve

This 5-day long workshop reunited researchers working on structural aspects of the endoplasmic reticulum (ER), its function and its relationship to other organelles. We were able to follow talks on ER structure and shape, on ER contact sites with mitochondria, Golgi apparatus, nucleus, or lysosomes, on lipid regulation in the ER and on ER stress and its particular effects in cell biology.

Amongst the researchers invited, Sophie Janssens (VIB, Ghent) talked about dendritic cells (DCs) and described the role of IRE1α in conventional type 1 DC (cDC1) maturation and engulfment capacities of apoptotic cells. IRE1α is an ER stress sensor, activated when the ER faces an accumulation of misfolded proteins and its role is to reduce the protein load and to re-establish cellular homeostasis. In cDC1, she showed that IRE1α is activated when apoptotic cells are engulfed, leading to cDC1 maturation, and correlating with the chemokine receptor CCR7 upregulation.

A high number of other talks gave us insights on ER contact sites with different organelles. Contact sites could be visualised with precision thanks to techniques such as FRET, Cryogenic-electron microscopy (cryo-EM) or Airyscan confocal microscopy (Jennifer Lippincott-Schwartz). ER-mitochondria contact sites were the most discussed, as a lot of new tethers bringing ER and mitochondria together were described (Luca Scorrano) and mechanisms of mitochondria fusion and fission involving the ER were reported (Gia Voeltz). ER-Golgi contact sites were explored as well, relating the proteins involved in ER export to the Golgi, through COPII vesicles, and the mechanism behind the export of different cargos (Liz Miller, Felix Campelo).

Protein translocation into the ER was highlighted through further description of the Sec61 translocon and the discovery of new complexes that could share this function (Maya Schuldiner). We also learn about on ER transmembrane proteins insertion and stabilisation through the Sec61 translocon (Manu Hedge, Bob Keenan).
Finally, lipid regulation through the ER was reviewed. The formation of lipid droplets from the ER membrane and how the organelle could mediate triacylglycerol and cholesterol synthesis or distribution were highlighted (Bruno Antonny, Tobias Walther).