Abstract
Autophagy is an intracellular process for vacuolar degradation of cytoplasmic components. We have found that C-terminus of Apg8 is modified with lipid by ubiquitination-like reaction after cleavage of C-terminus by APG4 protease and this Apg8 lipidation system is essential for autophagy. Existence of APG8 and APG4 orthologues in Arabidopsis implicates that, in plant autophagy which is not well study, these molecules would function in a similar way. All of nine AtAPG8 and two AtAPG4 were expressed in almost all organs of Arabidopsis and induced by nitrogen-starvation. It has been known that yeast Apg8 is delivered to the vacuole by autophagy. So I made transgenic plants expressed GFP-AtAPG8 fusion protein and observed various tissues by fluorescence microscopy. GFP-AtAPG8 localized on some dot structures of cytoplasm and lumens of vacuole. Observation of GFP-AtAPG8 under nitrogen-starvation condition is in progress. We will also report behavior of AtAPG8 in double mutant of AtAPG4.
