VMA16

..Recently, two VMA3 homologues, VMA11 and VMA16 (PPA1), have been identified in yeast, and VMA11 has been shown to be required for the V-ATPase activity...

..Our results suggest Voa1p functions with Vma21p early in V(0) assembly in the ER, but then it dissociates before exit of the V(0)-Vma21p complex from the ER for transport to the Golgi compartment...

..However, we report that subunit c'' is not essential for assembly but is for functional coupling of the enzyme...

..Thus SKG1 encodes a novel protein that affects the cell wall polymer composition in the growing region of the cell...

....

..Furthermore, a chimeric fusion between Vma16p and Vma3p, Vma16-Vma3p, was found to assemble into a fully functional V-ATPase complex, further supporting the conclusion that the ..

..Conversely, Stm1 accumulation induces cell death. In addition we identified five other genes whose overexpression in proteasomal mutants caused similar apoptotic phenotypes...

..Structural differences within the membrane-spanning domains of both V(0) and F(0) may account for the unique properties of the ATP-hydrolyzing V-ATPase compared with the ATP-generating F-type ATP synthase...

..Recent information concerning targeting and regulation of V-ATPases has also been obtained...

..However, the relative arrangement of the EG and C subunits in solution is more open than that in the holoenzyme, suggesting a conformational change of EGC during regulatory assembly and disassembly...

..Understanding V-ATPase function will provide important insights into diseases of the kidney (renal tubular acidosis), bone diseases (osteopetrosis), and in tumor metastasis, and new drug targets should arise from our studies. ..

..abstract_text> ..

..Additional functions for the assembly factors will be investigated such as escorting the V- ATPase into ER derived vesicles and chaperoning the complex to the cis-Golgi. ..

..These studies are likely to increase our basic understanding of diseases that result from missorting of lysosomal hydrolases such as Mucolipidosis II and III and other lysosomal storage diseases...

..The sighting of this mass spectrometer at the University of Oregon will make this technology immediately accessible to our researchers, rather than having to rely on long distance collaborations. ..

..The other two assembly factors, Vmal2p and Vma22p, will also be investigated for roles in assembly of the complex and for packaging of the V-ATPase into vesicles budding from the ER. ..

..Understanding V-ATPase function will provide important insights into diseases of the kidney (renal tubular acidosis), bone diseases (osteopetrosis), and in tumor metastasis, and new drug targets should arise from our studies. ..

..These basic mechanistic studies in yeast are providing important insights into our understanding of many lysosomal storage diseases in humans. ..

..Major equipment is shared and housed in common space. The laboratories of most of the faculty are contiguous and in interconnected buildings. This arrangement fosters interactions and collaborations among faculty and students. ..

..These basic studies in yeast are providing important insights into our understanding of many diseases in humans related to defects in organelle acidification. ..

..The long-term objective of the studies with the vacuolar H+- ATPase is to develop a mechanistic understanding of the pathway of assembly for this very complex membrane protein...

..Mutations will be constructed and their effects assessed in yeast cells by standard yeast genetic methodology. Antibodies to this protein will be used to test for its function in our cell-free Golgi to vacuole transport assay...

..the work described in this proposal should increase our understanding of the specificity of the enzyme defective in Mucolipidosis II and III and thus help elucidate the process of targeting lysosomal proteins in general...