biostudies-literatureZhou XAcademy of Finland (Suomen Akatemia)7808https://www.ebi.ac.uk/biostudies/studies/S-EPMC12371084biostudies-literatureUnknown16(1)Sac1 is a conserved phosphoinositide phosphatase, whose loss-of-function compromises cell and organism viability. Here, we employ acute auxin-inducible Sac1 degradation to identify its immediate downstream effectors in human cells. Most of Sac1 is degraded in ~1 h, paralleled by increased PI(4)P and decreased cholesterol in the trans-Golgi network (TGN) during the following hour, and superseded by Golgi fragmentation, impaired glycosylation, and selective degradation of TGN proteins by ~4 h. The TGN disintegration results from its acute deacidification caused by disassembly of the Golgi V-ATPase. Mechanistically, Sac1 mediated TGN membrane composition maintains an assembly-promoting conformation of the V0a2 subunit. Key phenotypes of acute Sac1 degradation are recapitulated in human differNature communicationsControl of Golgi- V-ATPase through Sac1-dependent co-regulation of PI(4)P and cholesterol.PMC12371084364185332096Vihinen HSasaki JLi HHoltta MMorioka SSasaki TZhou XLi SThiele CJokitalo EIkonen EKaptan Svan der Stoel MMPietilainen OVattulainen IfalseControl of Golgi- V-ATPase through Sac1-dependent co-regulation of PI(4)P and cholesterol.Sac1 is a conserved phosphoinositide phosphatase, whose loss-of-function compromises cell and organism viability. Here, we employ acute auxin-inducible Sac1 degradation to identify its immediate downstream effectors in human cells. Most of Sac1 is degraded in ~1 h, paralleled by increased PI(4)P and decreased cholesterol in the trans-Golgi network (TGN) during the following hour, and superseded by Golgi fragmentation, impaired glycosylation, and selective degradation of TGN proteins by ~4 h. The TGN disintegration results from its acute deacidification caused by disassembly of the Golgi V-ATPase. Mechanistically, Sac1 mediated TGN membrane composition maintains an assembly-promoting conformation of the V0a2 subunit. Key phenotypes of acute Sac1 degradation are recapitulated in human differ2025-01-01T00:00:00Z2025 Aug2026-05-08T06:53:01.251Z2026-04-07T23:31:16.675ZS-EPMC123710844084155810.1038/s41467-025-63125-7