Séminaire IBIP
Les séminaires ont lieu sur le Campus Montpellier SupAgro/INRA de La Gaillarde (2, place P. Viala Montpellier)

Jeudi 9 octobre 2014
Salle 104 (Château) à 14h

How plastid proteins find their way to the vacuole for degradation: a unique process that uses selective-autophagy

Simon Michaeli
BPMP, Equipe Ubistress

Selective-autophagy has been extensively studied in various organisms, but knowledge regarding its functions in plant cells, particularly in organelles turnover, is limited. We have recently discovered an Arabidopsis Atg8-binding protein, termed ATI1, and showed its involvement ER-to-vacuole trafficking through special ER localized bodies. In this presentation I will further show that following carbon starvation, ATI1 is also incorporated to specific bodies located within plastids. These plastid ATI-bodies are distinct from the ER ATI-bodies and they are detected mainly in senescing cells that exhibit plastid degradation. Additionally, these plastid localized bodies contain a stroma protein marker as cargo and were observed budding from plastids into the cytosol. ATI1 interacts with specific plastid proteins that were further detected as cargo of these ATI plastid bodies. Moreover, ATI1 was shown to be required for the turn-over of one of these plastid-localized ATI1-interacting proteins, as a representative. ATI1, located on these bodies, also interacts with Atg8, which subsequently leads to their targeting to the vacuole by a process that requires functional autophagy. Finally, we show that the trafficking pathways involving ATI1 are required for proper salt stress tolerance. Together, our results implicate ATI1 in an autophagic plastid-to-vacuole trafficking through its ability to interact with both plastid proteins and Atg8 of the core autophagy machinery.

Contact : Simon Michaeli

Contacts IBIP :
Sabine Zimmermann
Alexandre Martiniere
Christine Granier
Chantal Baracco