Watanabe Y, Suzuki K. The activation mechanism of Atg15, a vacuolar phospholipase required for the disintegration of organelle membranes.
Autophagy 2024:1-2. [PMID:
38513722 DOI:
10.1080/15548627.2024.2333165]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 03/15/2024] [Indexed: 03/23/2024] Open
Abstract
The disintegration of cytoplasm-to-vacuole targeting (Cvt) bodies and autophagic bodies in vacuoles is essential to the Cvt pathway and macroautophagy in yeast. Atg15 is a vacuolar lipase required for the degradation of both Cvt and autophagic bodies. However, the molecular mechanism of their degradation by Atg15 remains poorly understood. In a recent study, we showed that recombinant Chaetomium thermophilum Atg15 (CtAtg15) possesses phospholipase activity, and that this activity is significantly elevated by proteolytic cleavage at a site away from the active center. The proteolytic cleavage of CtAtg15 causes a conformational change around the active center, resulting in the active open state. Interestingly, activated CtAtg15 can degrade not only Cvt and autophagic bodies but also organelle membranes. On the basis of these results, we propose an activation mechanism by which Atg15, as an "organellase," functions only in vacuoles.
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