Atg23 prevents aberrant fusion of Atg9 vesicles during delivery to autophagosome formation sites.

Atg23 prevents inappropriate fusion of Atg9 vesicles during autophagosome formation in yeast, ensuring proper membrane delivery for autophagy.

• Why it matters: Understanding how Atg9 vesicles are accurately trafficked without fusion errors is crucial for revealing autophagosome biogenesis mechanisms, which are vital for cellular health and disease prevention.
• What they did: The study examined Saccharomyces cerevisiae and found that Atg23 remains bound to Atg9 vesicles after formation, shielding them from SNARE-dependent fusion during cytoplasmic transport, and identified a phosphorylation switch regulating this process.
• The result: This work uncovers an Atg1-dependent phosphorylation mechanism that controls Atg9 vesicle dynamics, enabling precise membrane delivery and facilitating subsequent steps in autophagosome formation.