Aims
We previously reported that yeast Atg15 is a phospholipase B-type enzyme with broad substrate specificity (Kagohashi et al., JCB 2023). Such properties suggest that its activity must be tightly regulated in vivo. This study aimed to identify factors that regulate Atg15 function in yeast.
Methods
We performed immunoprecipitation (IP) assays using epitope-tagged Atg15 to identify interacting proteins from yeast lysates.
Results
We identified a previously uncharacterized vacuolar protein that specifically binds to Atg15. Localization studies confirmed that this protein resides in the vacuole. Functional analysis revealed that it inhibits the enzymatic activity of Atg15, suggesting it acts as a negative regulator.
Conclusions
These findings reveal a novel mode of regulation for Atg15 through physical interaction with a vacuolar inhibitory factor, providing new insights into the control of lipase activity within the cell.