Vacuole function

Vacuoles function in transport and storage of nutrients and cellular waste products. 

Doberstein, S.K., Baines, I.C., Wiegand, G., Kom, E.D., Pollard, T.D. (1993). Inhibition of contractile vacuole function in vivo by antibodies against myosin-I. Nature 365, 841-843. 

S ATP -I- 1-phosphatidyl-1 D-myo-inositol 3-phosphate <1, 2> (<1>, stress-activated enzyme [1] <1>, essential for vacuole function [1] <1>, generation of 1-phosphatidyl-1 D-myo-inositol 3,5-hisphosphate is regulated... 

Cooke, F.T. Dove, S.K. McEwen, R.K. Painter, G. Holmes, A.B. Hall, M.N. Michell, R.H. Parker, P.J. The stress-activated phosphatidylinositol 3-phosphate 5-kinase Fablp is essential for vacuole function in S. cerevisiae. Curr. Biol., 8, 1219-1222 (1998)... 

Yamamoto, A., DeWald, D.B., Boronenkov, I.V, Anderson, R.A., Emr, S.D. and Koshland, D., 1995, Novel PI(4)P 5-kinase homologue, Fablp, essential for normal vacuole function and morphology in yeast. Mol. Biol. Cell 6 525-539. 

All V-class ATPases transport only ions. These proton pumps, present in the membranes of lysosomes, endosomes, and plant vacuoles, function to acidify the lumen of these organelles. The pH of the lysosomal lumen can be measured precisely in living cells by use of particles labeled with a pH-sensitive fluorescent dye. After these particles are phagocy-tosed by cells and transferred to lysosomes, the lysosomal pH can be calculated from the spectrum of the fluorescence emitted. Maintenance of the 100-fold or more proton gradient between the lysosomal lumen (pH 4.5-5.0) and the cytosol (pH 7.0) depends on ATP production by the cell. 

It is misleading to consider that ROS are always deleterious, and that to prevent release or action of ail ROS will be of therapeutic value. One could reason that some ROS are released without control or purpose, as by-products of the normal metabolism of eicosanoids, or during oxidative phosphorylation in the mitochondria. However, during normal function, inflammatory ceUs appropriately release ROS both intracellularly into vacuoles and extracellularly in order to kill foreign organisms in host defence. Also, nitric oxide is a radical species whose principal role in the lung appears to be the control of pulmonary vascular tone and platelet function. Nevertheless, there are clear examples where fhistrated phagocytosis could explain an excessive release of ROS in... 

ALFENITO, M.R., SOUER, E GOODMAN, C.D., BUELL, R., MOL, J., KOES, R., WALBOT, V., Functional complementation of anthocyanin sequestration in the vacuole by widely divergent glutathione 5-transferases, Plant Cell, 1998,10,1135-1149. 

Vacuoles (70-78) are membrane-bound regions of the cell filled with cell sap. Vacuoles are surrounded by a tonoplast (vacuolar membranes) and are diverse with distinct functions. Most investigators believe that lysosomes and the plant vacuoles are the same. Vacuoles develop turgor pressure and maintain tissue rigidity. They are storage components for various metabolites such as reserve proteins in seeds and malic acid in crassulacean acid metabolism (CAM) plants. Vacuoles canremove toxic secondary products and are the sites of pigment deposition. 

As we saw in Chapter 7, zinc uptake in plants involves proteins of the ZIP family, some of which are root specific while others are found in both roots and shoots. The transport of zinc from the cytosol in many organisms is often associated with members of the cation diffusion facility (CDF) family. Although there are 12 predicted family members in Arabidopsis, only one, MTP1, has been characterized, which seems to function in the transport of Zn into the vacuole. Two members of the heavy metal ATPase (HMA) family, HMA2 and HMA4, have been shown to function in the transport of zinc out of the cells across the plasma membrane. 

The lysosome is an acidic organelle containing many hydrolases and can degrade most biological macromolecules (Kornfeld and Mellman, 1989). The vacuole in yeast and plants is thought to be its functional relative. Both of them are bounded by a single membrane and have... 

Vacuoles Any spaces or cavities within a cell. They may function in digestion, storage, secretion, or excretion, [nih]... 

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