Identification of factors determining vacuole morphology together with AMSH3 in Arabidopsis thaliana

• Applicant: Professorin Dr. Erika Isono
• Subject Area: Plant Cell and Developmental Biology
• Term: from 2011 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 192037990

We have recently identified the Arabidopsis AMSH3 protein, a deubiquitinating enzyme, as a novel factor in the vacuolar biogenesis and cellular trafficking pathway. amsh3 mutants are seedling lethal, lack large central vacuoles and show defects in vacuolar transport. The vacuole (lysosome) exist also in yeast and animal cells, and although its biogenesis has been intensively studied in yeast cells, the involvement of a deubiquitinating enzyme in this process was not reported in other organisms, suggesting that there might be a distinct mechanism for vacuole biogenesis in plants. The experiments described in this proposal aim (1) at understanding the role of AMSH3 and ubiquitination in the context of other factors by characterizing vacuole fusion defective (vfd) mutants and thereby identifying factors that function in the same pathway as amsh3 in vacuole biogenesis; and (2) at elucidating the function of an Arabidopsis small GTPase family, RAB7;G, in vacuole biogenesis as a possible AMSH3 substrate candidate. Taking advantage of both forward and reverse genetics, this research will allow us to gain deeper insights into the mechanism of vacuole biogenesis in Arabidopsis and the role of ubiquitination in this process.

• DFG Programme: Research Grants