PSI-mediated Vacuolar Sorting is not Disrupted in Arabidopsis <em>leb</em>-2 Mutant

Abstract

The endomembrane system in plant cells enables the cell to manage and coordinate a variety of membranous compartments so that they and their contents arrive at the right location. The secretory pathway takes part in this complex network and has its gateway at the Endoplasmic Reticulum. Therefore, alterations at the Endoplasmic reticulum level could condition how protein trafficking takes place or, at least, influence how such cargo leaves this organelle. With this work, we intended to assess how abnormalities at the Endoplasmic Reticulum would interfere with protein sorting and trafficking. Thus, we used a novel Arabidopsis mutant - leb-2 GFP-h -, presenting ER morphology alterations. Our results show that alterations in the leb-2 GFP-h mutant did not disrupt PSI A/B–mCherry transport to the vacuole but influences the expression of endogenous aspartic proteinases. Furthermore, the study of key-endomembrane genes expression revealed an upregulation of the SNAREs AtVAMP722 and AtVAMP723. As a whole, the leb-2 mutant seems not to interfere with vacuolar routes but may be implicated in secretion events.