biostudies-literatureUnknown27(15)Du FThe contractile vacuole (CV) system is the osmoregulatory organelle required for survival for many free-living cells under hypotonic conditions. We identified a new CV regulator, Disgorgin, a TBC-domain-containing protein, which translocates to the CV membrane at the late stage of CV charging and regulates CV-plasma membrane fusion and discharging. disgorgin(-) cells produce large CVs due to impaired CV-plasma membrane fusion. Disgorgin is a specific GAP for Rab8A-GTP, which also localizes to the CV and whose hydrolysis is required for discharging. We demonstrate that Drainin, a previously identified TBC-domain-containing protein, lies upstream from Disgorgin in this pathway. Unlike Disgorgin, Drainin lacks GAP activity but functions as a Rab11A effector. The BEACH family proteins LvsA andThe EMBO journal2064-76https://www.ebi.ac.uk/biostudies/studies/S-EPMC2516880biostudies-literatureRegulation of contractile vacuole formation and activity in Dictyostelium.PMC2516880Briggs SShen ZSun BDe Lozanne ADu FFirtel RAEdwards KfalseRegulation of contractile vacuole formation and activity in Dictyostelium.The contractile vacuole (CV) system is the osmoregulatory organelle required for survival for many free-living cells under hypotonic conditions. We identified a new CV regulator, Disgorgin, a TBC-domain-containing protein, which translocates to the CV membrane at the late stage of CV charging and regulates CV-plasma membrane fusion and discharging. disgorgin(-) cells produce large CVs due to impaired CV-plasma membrane fusion. Disgorgin is a specific GAP for Rab8A-GTP, which also localizes to the CV and whose hydrolysis is required for discharging. We demonstrate that Drainin, a previously identified TBC-domain-containing protein, lies upstream from Disgorgin in this pathway. Unlike Disgorgin, Drainin lacks GAP activity but functions as a Rab11A effector. The BEACH family proteins LvsA and2008-01-01T00:00:00Z2008 Aug2026-03-16T16:25:45.188Z2019-03-27T00:16:12ZS-EPMC25168801863609510.1038/emboj.2008.131