Abstract:

Interactions between different subcellular organelles are essential for individual organelle function and for the maintenance of overall cellular homeostasis. Over the last decade membrane contact sites, regions where apposing organelle membranes are brought into close proximity via the action of protein tethers, have emerged as key sites where organelle communication takes place.  Recent work recent has shown that essentially all organelles interact with each other to different extents and at least 44 different types of contact site involving 263 different tethering complexes have been identified to date.   Peroxisomes, organelles with a critical role in both lipid and ROS homeostasis, are no exception and interact with the ER, mitochondria, lipid-droplets and lysosomes. These interactions allow lipid transfer, specifically of the very long chain fatty acid substrates which are only able to be processed by peroxisomes. Most notably, highly extensive interactions between peroxisomes and the ER have been observed for decades in ultrastructural studies of mammalian cells but until recently the mechanism and importance of such interactions remained unclear.  

Here, I will present our work on the tethering proteins ACBD5, ACBD4 and VAPB, which physically link peroxisomes to the ER to allow exchange events between the organelles. I will discuss new data on mechanisms to regulate this tethering, present a novel potential function of peroxisome-ER tethers in mitosis and highlight how loss of ER-peroxisome interactions is linked to disease.  

 

Hosted by James Lythall and Helen Weavers