Vacuole

The vacuole is a generally large fluid-filled membrane-bound compartment in the cytoplasm. The precise form and function of vacuoles may vary between phyla. Plant vacuoles are among the best characterized. They differ in terms of their lumenal contents and processing enzymes, as well as on the basis of the type of integral proteins in their membranes (tonoplast intrinsic proteins, TIPs). Examples include the lytic vacuole, the storage vacuole and the lutoid. One important function of plant vacuoles is the maintenance of hydrostatic pressure. Other eukaryotes employ vacuoles for a variety of purposes, including storage (as in the yeast lysosome/vacuole), secretion and phagocytosis. In Protozoa, contractile vacuoles can be used to discharge water from the cytoplasm to the external environment. Aquatic microorganisms may employ gas vacuoles (composed of clusters of inert gas vesicles) to provide buoyancy.

Source:http://purl.uniprot.org/locations/272