Figure 7. Phosphorylation of a conserved regulatory surface of Sec24 enhances the ability of the COPII coat to recognize the autophagy machinery.
Phosphorylation of the Sec24 membrane distal sites regulates the interaction of Sec24 with the C-terminus of Atg9. During starvation, the Sec24-Atg9 interaction is needed to increase autophagosome number. If Sec24 is not phosphorylated, it is unable to efficiently interact with Atg9 and COPII vesicles traffic to the Golgi.
Figure 7—figure supplement 1. Sec13-GFP accumulates at the PAS in the atg9∆ mutant.
(A) WT and atg9∆ cells expressing Sec13-GFP and Ape1-RFP were starved for nitrogen for 2 hr at 30°C and the percent of Ape1-RFP that colocalized with (left) or was adjacent to (right) Sec13-GFP was determined for over 300 cells from three biological replicates. When the COPII vesicles accumulate in the atg9∆ mutant, fewer are found adjacent to the PAS. Averages and s.e.m. are shown for three biological replicates. p-value = 0.018 (colocalized), 0.01 (adjacent to), Student’s unpaired t-test. *p<0.05. (B) Representative images quantitated in (A). Scale bar 2 µm. Arrowheads mark the PAS.