MTV proteins unveil ER- and microtubule-associated compartments in the plant vacuolar trafficking pathway.

The factors and mechanisms involved in vacuolar transport in plants, and in particular those directing vesicles to their target endomembrane compartment, remain largely unknown. To identify components of the vacuolar trafficking machinery, we searched for () mutants that abnormally secrete the synthetic vacuolar cargo VAC2. We report here on the identification of 17 mutations, corresponding to mutant alleles of , , , , , , , , , , , and Eight of the MTV proteins localize at the interface between the -Golgi network (TGN) and the multivesicular bodies (MVBs), supporting that the trafficking step between these compartments is essential for segregating vacuolar proteins from those destined for secretion.

Plant Cells under Attack: Unconventional Endomembrane Trafficking during Plant Defense.

Since plants lack specialized immune cells, each cell has to defend itself independently against a plethora of different pathogens. Therefore, successful plant defense strongly relies on precise and efficient regulation of intracellular processes in every single cell. Smooth trafficking within the plant endomembrane is a prerequisite for a diverse set of immune responses.

SEIPIN Proteins Mediate Lipid Droplet Biogenesis to Promote Pollen Transmission and Reduce Seed Dormancy.

Lipid droplets (LDs) are ubiquitous organelles in plant cells, but their physiological roles are largely unknown. To gain insight into the function of LDs in plants, we have characterized the Arabidopsis homologs of SEIPIN proteins, which are crucial factors for LD biogenesis in yeast and animals. is expressed almost exclusively in embryos, while and have broader expression profiles with maximal levels in embryos and pollen, where LDs accumulate most abundantly.