Current Projects

Our research focuses on the regulation of vesicle trafficking mechanisms in plant cells. Our goal is to understand how cells control the flow of proteins and specialized metabolites between different cellular compartments. We are currently working on the following projects:

Endosomal sorting of membrane proteins for degradation:

Cells are able to interact with other cells and their environment through molecules located in their surface and therefore, it is critical for a cell to be able to control the protein composition of its plasma membrane. We are analyzing the mechanisms that mediate the recognition and degradation of plasma membrane proteins in plants. These mechanisms allow cells to control the abundance of key plasma membrane proteins involved in cell signaling, growth, and development, such as activated receptors, hormone transporters, and ion channels. The degradation of plasma membrane proteins is mediated by membrane-bound organelles called endosomes. Plasma membrane proteins internalized by endocytosis are sorted for degradation in endosomes called multivesicular endosomes (MVEs). 
We are focusing on understanding how endocytosed plasma membrane proteins, such as activated receptors, auxin transporters, and ion channels, are recognized in endosomes and sorted for degradation. Soluble proteins that are not anchored into membranes can be degraded by cytoplasmic proteases that belong to the 26S-proteasome degradation pathway. But how does a cell degrade a protein that is inserted in the plasma membrane? Most plasma membrane proteins are flagged for degradation at the plasma membrane by ubiquitination. ESCRT proteins recognize ubiquitinated membrane proteins and sort them into intraluminal vesicles, giving rise to MVEs. When MVE fuse with lysosomes/vacuoles, the endosomal vesicles are released in the vacuolar lumen and degraded.

Autophagy:

Autophagy mechanisms Autophagy is the process by which cytoplasmic material is delivered to the vacuole for storage or degradation. We are characterizing both conventional and unconventional autophagy processes that operate in plants and do not seem to depend on the canonical autophagy machinery. We have identified conserved autophagy (ATG) components that are critical for the recycling on carbon and nitrogen in maize.  We are currently focusing on the function of cell type-specific autophagic pathways to improve maize resilience in field conditions.