Rojas Pierce Laboratory
 

RESEARCH

Protein Trafficking to the Plant Vacuolar Membrane

Research in our lab is focused on targeting mechanisms for plant tonoplast proteins using both classical genetic and chemical genetic approaches.

Tonoplast membrane transporters carry out the movement of molecules in and out of the plant vacuole including lipids, ions, sugars, hormones and defense molecules. The transport of molecules across the tonoplast is essential for plant vacuolar function, including the maintenance of cellular turgor and ion sequestration, which ultimately control osmotic potential of the cytosol. To improve plant stress tolerance and ultimately increase the nutritional value of plants for human consumption, it is essential that we understand how to regulate vacuolar trafficking of membrane proteins.

 

Novel inhibitors of tonoplast protein trafficking

In order to characterize trafficking pathways of tonoplast proteins, we identified chemical inhibitors that affect protein trafficking to the vacuole. One inhibitor, named C834, inhibits the targeting of the GFP-TIP2;1 marker protein to the tonoplast.

Using C834 treatments as well as other pharmacological tools, our group has shown that, in Arabidopsis, TIP3;1 and TIP2;1 are likely to use a Golgi-independent pathway, while TIP1;1 is likely to use a Golgi-dependent pathway. It is unknown at this point why these proteins are bypassing the Golgi, and how these closely related proteins are being targeted to each pathway.

C834 inhibits the targeting of the GFP-TIP2;1 marker protein to the tonoplast.

 

Novel regulators of tonoplast protein trafficking and vacuole biogenesis

With the goal of identifying proteins that regulate the trafficking pathway for TIP2;1, we have identified mutants in which these proteins are mis-localized. One of these mutants highlighted the role of a SNARE protein and phosphoinositides in vacuole fusion.

Loss of function alleles of VTI11 have many vacuoles per cell

We are currently characterizing the role of VTI11 SNARE in vacuole fusion during the development of the large central vacuole. This protein is critical for the normal morphology of the vacuole as evidenced by the mutant phenotypes of itt3, a new allele for this locus.

 

 

 

Outreach Research People

Our lab is very active in outreach activities. We have hosted several High-school students and will soon start hosting 7th and 8th graders from a local Middle school in Raleigh.

Research in our lab is focused on targeting mechanisms for tonoplast proteins in Arabidopsis. We use chemical and classical genetic approaches to understand trafficking mechanisms and vacuole biogenesis.
An important goal of our lab is the training of outstanding graduate and undergraduate students and postdocs.
     
 
ROJAS-PIERCE LABORATORY- North Carolina State University.