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Regulation of contractile vacuole formation and activity in Dictyostelium
Author(s) -
Du Fei,
Edwards Kimberly,
Shen Zhouxin,
Sun Binggang,
De Lozanne Arturo,
Briggs Steven,
Firtel Richard A
Publication year - 2008
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2008.131
Subject(s) - biology , dictyostelium , contractile vacuole , vacuole , microbiology and biotechnology , mycetozoa , biochemistry , gene , cytoplasm
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 and LvsD were identified in a suppressor/enhancer screen of the disgorgin − large CV phenotype and demonstrated to have distinct functions in regulating CV formation. Our studies help define the pathways controlling CV function.