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Drainin required for membrane fusion of the contractile vacuole in Dictyostelium is the prototype of a protein family also represented in man
Author(s) -
Becker Michael,
Matzner Monika,
Gerisch Günther
Publication year - 1999
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 - 10.1093/emboj/18.12.3305
Subject(s) - biology , contractile vacuole , vacuole , microbiology and biotechnology , dictyostelium , lipid bilayer fusion , caenorhabditis elegans , vesicle associated membrane protein 8 , membrane protein , cytosol , membrane , biochemistry , gene , cytoplasm , enzyme
The contractile vacuole expels water by forming a channel with the plasma membrane and thus enables cells to survive in a hypo‐osmotic environment. Here we characterize drainin, a Dictyostelium protein involved in this process, as the first member of a protein family represented in fission yeast, Caenorhabditis elegans and man. Gene replacement in Dictyostelium shows that drainin acts at a checkpoint of channel formation between the contractile vacuole and the plasma membrane. A green fluorescent protein fusion of drainin localizes specifically to the contractile vacuole and rescues its periodic discharge in drainin‐null cells. Drainin is a peripheral membrane protein, requiring a short hydrophobic stretch in its C‐terminal region for localization and function. We suggest that drainin acts in a signaling cascade that couples a volume‐sensing device in the vacuolar membrane to the membrane fusion machinery.