Sorting and Transport of Proteins into the Dense Vesicle Pathway

• Applicant: Professor Dr. David G. Robinson
• Subject Area: Plant Cell and Developmental Biology
• Term: from 2004 to 2009
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5442874

Storage protein accumulation is a unique feature of plant seeds which is of huge agricultural importance. Here we focus our attention on the specific problem of how the globulin class of storage proteins is recognized and sorted within the endomembrane system. Previous work in our laboratory has established that these proteins are separated from secretory proteins early during their transport through the Golgi apparatus, and packaged into specific carrier vesicles: "dense vesicles, dv". The mechanism of this process is unknown. We intend to carry out a functional characterization of LBP48, an integral membrane protein in pea cotyledons which specifically binds legumin, in order to define its role in protein sorting. We will also critically examine the situation with respect to VSR1, a protein previously shown to be a receptor for acid hydrolases, in the sorting of globulins into developing Arabidopsis cotyledons. In order to ascertain the importance of hydrophobic sequences as sorting determinants for the dv-pathway, we have devised a novel in situ assay using fusion-constructs of the neutral cargo molecule PAT. Finally, we plan to determine whether the enzymes required for storage protein processing are transported in different Golgi-derived vesicles.

• DFG Programme: Research Grants