Abstract Detail

Genetics Section

Rad, Sara Abolhassani [1], Kohalmi, Susanne E [1].

Analyzing the non-enzymatic role of Arogenate dehydratase 5 in Arabidopsis thaliana .

The final step of phenylalanine biosynthesis in planta is catalyzed by arogenate dehydratases (ADTs). In the Arabidopsis thaliana genome, six genes (ADT1- ADT6) were identified that code for this type of enzyme. Previously in our lab, all ADTs were cloned as ADT- CFP fusion genes and their subcellular localization were studied. Through co-localization of ADT-CFPs, it is shown that all ADTs localize to stroma-filled projections from chloroplasts called stromules, a likely place for their enzymatic role of these proteins in the cell. Surprisingly some of ADTs show additional unique localization pattern. For example ADT5 is found to localize to the nucleus, which suggests an uncharacterized nuclear role for this protein. Such multifunctional proteins are referred to as moonlighting proteins, as they have additional and often unexpected functions in the cell. The nuclear localization of ADT5 suggests a role in gene transcription. ADT5 uses a transit peptide to enter to the chloroplast and for targeting ADT5 to the nucleus we examined two possibilities: 1) the protein could use an internall Nuclear Localization Sequence (NLS), 2) the protein could interact with other proteins to be imported into the nucleus by “piggyback”. Several deletion constructs for ADT5 were generated and using confocal microscopy the localization of the truncated proteins was investigated. ADT5 is suggested to have an interaction with importin α isoform 6 (IMPA-6). Importin proteins are usually involved in the import of proteins into the nucleus. We used the yeast 2-hybrid system and the Bi- molecular Fluorescence Complementation system (BiFC) to determine if these two proteins are able to interact and if IMPA6 targets ADT5 into the nucleus. Results will be shown and discussed. This project is part of a larger analysis characterizing differences and similarities of closely related proteins to understand the role of protein families.

1 - Western Univerity, Biology, 1151 Richmond Street North, London, Ontario, N6A 5B7, Canada

Keywords:
arogenate dehydratase 5
phenylalanine biosynthesis
nuclear localization
Chloroplast localization.

Presentation Type: Oral Paper:Papers for Sections
Session: 6
Location: Salon 15/16/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 9:00 AM
Number: 6005
Abstract ID:1154
Candidate for Awards:Margaret Menzel Award