Proton-ATPase

Tcirgl (ATP6i) A3 subunit of the vacuolar proton ATPase oc allele in the monse Osteopetrosis with increased number of inactive osteoclasts, failure of tooth eruption Majority of cases of malignant infantile osteopetrosis Chondrodysplasia, small size, premature death... 

Ludwig,J., Kerscher, S., Brandt, U., Pfeiffer, K., Gedawi, F., Apps, D. K., and Schagger, H. (1998). Identification and characterization of a novel 9.2-kDa membrane sector-associated protein of vacuolar proton ATPase from chromaffin granules. J. Biol. Chem. 273, 10939-10947. 

McEnery, M. W., Buhle, E. L.,Jr, Aebi, U., andPedersen, P. L. (1984). Proton ATPase of rat liver mitochondria Preparation and visualization of a functional complex using the novel zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-l-propanesulfonate./. Biol. Chem. 259, 4642-4651. 

Xie, X. S., and Stone, D. K. (1988). Partial resolution and reconstitution of the subunits of the clathrin-coated vesicle proton ATPase responsible for Ca2+-activated ATP hydrolysis. /. Biol. Chem. 263, 9859-9867. 

Her research interests originally focused on biological cell membranes, first working on phosphate transport in Escherichia coli and then the plasma membrane proton ATPase in Saccharomyces cerevisiae. While isolating vanadate-resistant mutants in yeast, she became fascinated with work showing that oral administration of vanadium salts alleviated symptoms of diabetes and switched her research focus to that area. She has pursued the insulin-enhancing mechanism of vanadium salts and complexes in cell culture, the STZ-induced diabetic rat, and human type 2 diabetic patients. The National Institutes of Health, the American Heart Association, and the American Diabetes Association have funded the work in her laboratory. Willsky has lectured all around the world and published both research articles and book chapters in this area. 

N. Nelson (1992). Evolution of organeller proton-ATPases. Biochim. Biophys. Acta, 1100, 109-124. 

The proton-ATPase complex, first purified by Pick and Racker [54], was reported to contain nine different subunits, four of which may belong to the membrane sector. Later studies in our laboratory detected only three subunits in the... 

Subunit structure and function of the proton ATPase complex... 

Fig. 12.1. Relative sizes of mitochondrial and chloroplast chromosomes and location of protein structural genes. The figure was constructed from published data [5,15,17,22,26-28]. The structural genes are marked by wide sections. Black areas code for proteins. White areas are introns. 0x1, OxII and OxIII are subunits I, II and III of cytochrome c oxidase. Cyt b, cytochrome b. Fo and Fo, are subunits 6 and 9 of the proton ATPase complex. In the chloroplast chromosome the arrows indicate the transcription direction and the size of the transcripts. CF,a, CFj/8, CFjc and CFoIII are subunits a, /S, t and III of the chloroplast proton ATPase complex [30]. PSII5], PSII44, and PSII34 are subunits of photosystem II reaction center with the corresponding molecular weights of 51000, 44000 and 34000. PSI70 is subunit I of photosystem I reaction center. Cyt /is cytochrome/ cyt is cytochrome b and b -flV is subunit IV of cytochrome b(,-f complex.

Once the chromaffin granule is formed, low molecular components such as catecholamines, ATP and Ca are concentrated in the cisterna using the proton motive force provided by a proton ATPase [39,45]. Upon receiving stimulus, the granules fuse with the plasma membrane and the catecholamines are released from the cell. To prevent continual growth of the plasma membrane, portions of it must... 

The energy dependence of import into mitochondria has been exploited to accumulate large amounts of precursors in an uncoupler-poisoned living cell [93]. Precursor to the 8-subunit of the proton ATPase has been purified from such cells by affinity chromatography on an antibody column, followed by chromatofocussing and isoelectric focussing. After renaturation, this precursor can be correctly processed by the matrix protease and can be imported into mitochondria, but only in the presence of a proteinaceous factor from the yeast cytoplasm [94]. A similar finding has been reported for import of precursors into rat liver mitochondria in which a factor is provided by the reticulocyte lysate [95,96]. 

Fig. 12.6. The onset of synthesis of various mitochondrial polypeptides upon transferring anaerobically grown yeast cells to aerobic conditions. Yeast cells were grown overnight under anaerobic conditions. At time zero they were transferred to aerobic conditions, and at the indicated time periods samples of cells were removed and lysed in the presence of NaOH and mercaptoethanol. Samples containing about 50 /ig of protein were electrophoresed in a sodium dodecyl sulfate-polyacrylamide gel. The proteins were electrotransferred to nitrocellulose sheets and decorated with specific antibodies and l-labelled protein A. Paper pieces corresponding to the labelled protein spots were cut out from the immune blot and counted in a y counter. The amount of counts obtained in the samples of 8 h aerobic conditions was taken as 100%. The antibodies used were directed against the following polypeptides porin of the mitochondrial outer membrane (29 k) /8 subunit of the proton-ATPase (iS-F,) subunit IV of cytochrome c oxidase (OxIV) and subunit V of cytochrome c oxidase (OxV).

Nelson. N. (1991) Structure and pharmacology of the proton-ATPases. Trends Pharmacol. Sci., 12. 71-75. 

Smeulders MJ, Keer J, Speight RA, Williams HD. Adaptation of Mycobacterium smegmatis to stationary phase. J Bacteriol 1999 181 270-83. Sturgill-Koszycki S, Schlesinger PH, Chakraborty P, Haddix PL, Collins HL, Fok AK, Allen RD, Gluck SL, Heuser J, Russell DG. Lack of acidification in Mycobacterium phagosomes produced by exclusion of the vesicular proton-ATPase. Science 1994 263 678-81. 

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