Pilot Project 8 (2022)

Shedding light on inter-organellar communication: An optogenetic approach to investigate organelle contact sites

The group of Maria Bohnert investigates the biology of organelle contact sites, specialized structures where the membranes of different cellular organelles are physically linked to each other by so-called tether proteins. Contact sites act as hubs for interorganellar communication and hotspots for metabolism, and have diverse roles in organelle positioning, membrane biogenesis, and membrane dynamics (1). Systematic studies indicate that all types of organelles form contacts with each other (2; 3; 4). Famous examples in yeast include the nucleus-vacuole junction NVJ between the nuclear endoplasmic reticulum (ER) and vacuoles (5), the ER-mitochondria encounter structure ERMES (6) and the contact site between the cortical ER and the plasma membrane (7).

Research over the past years has uncovered that many contact sites are not static, but instead respond dynamically to environmental cues (8). This is exciting, as a metabolically controlled remodelling of membrane interfaces may allow the cell to coordinate the responses of different organelles to environmental changes, and to propagate signals across multiple membrane systems. Unfortunately however, we are currently lacking tools for targeted dynamic manipulation of organelle contact sites, impeding experimental access to this important aspect of contact site biology.