Organelle homeostasis in the plant secretory pathway

Understanding how cells maintain efficient compartmentalization and control the delivery and integration of bio-molecules into specialized organelles is a fundamental challenge in eukaryotic cell biology. The secretory pathway is an exquisite example of complexity for biomolecule trafficking and compartmentalization. The plant secretory pathway is responsible for the biosynthesis of one third of the cellular proteome, essential lipids and protein-modifying sugars. The life of these biomolecules starts in the endoplasmic reticulum (ER). They are then shuttled to the Golgi apparatus and the trans-Golgi network for sorting and delivery to target compartments. A striking feature of the organelles of the secretory pathway is the enormous difference in morphology, which is coupled to a tight functional diversity. To learn about how the secretory organelles establish and maintain their morphology and how the underlying mechanisms may influence their function as well as the function of other organelles, we have carried out forward genetic screens with fluorescent reporters to markers of proximal and distal compartments of the secretory pathway. Through these screens we have identified novel plant-specific as well as conserved factors that will be presented in this talk.