Abstract
We have developed two independent assays to study the integration, folding, and intracellular transport of the polytopic plasma membrane H(+)-ATPase in yeast. To follow folding, controlled trypsinolysis was used to distinguish between the E1 conformation of the ATPase (favored in the presence of ADP) and the E2 conformation (favored in the presence of vanadate). By this criterion, wild-type ATPase appears to recognize its ligands and assume distinct conformations within a short time after its biosynthesis. To follow intracellular transport, we have exploited the fact that export of newly synthesized ATPase from the endoplasmic reticulum is accompanied by kinase-mediated phosphorylation, leading to a shift in electrophoretic mobility. Because proper folding is required for transport from the endoplasmic reticulum, the mobility shift also serves as a convenient bioassay for correct folding. As a first step toward identifying cell components important in folding of the nascent ATPase, we have used the dual assays to examine the role of KAR2, encoding the yeast homolog of immunoglobulin heavy chain binding protein/78-kDa glucose-regulated protein, and SEC65, encoding a subunit of the yeast signal recognition particle. Although mutation of KAR2 caused defective translocation of several secretory precursors into the endoplasmic reticulum lumen, ATPase folding and intracellular transport were unperturbed. By contrast, in a sec65 mutant, the folding and intracellular transport of newly synthesized ATPase were delayed. Our data suggest that conformational maturation of the ATPase is a rapid process in wild-type cells and that membrane integration mediated by signal recognition peptide is important for the proper folding of this polytopic protein.
Full text
PDF




Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Amaya Y., Nakano A. SRH1 protein, the yeast homologue of the 54 kDa subunit of signal recognition particle, is involved in ER translocation of secretory proteins. FEBS Lett. 1991 Jun 3;283(2):325–328. doi: 10.1016/0014-5793(91)80619-e. [DOI] [PubMed] [Google Scholar]
- Chang A., Slayman C. W. Maturation of the yeast plasma membrane [H+]ATPase involves phosphorylation during intracellular transport. J Cell Biol. 1991 Oct;115(2):289–295. doi: 10.1083/jcb.115.2.289. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Deshaies R. J., Kepes F., Böhni P. C. Genetic dissection of the early stages of protein secretion in yeast. Trends Genet. 1989 Mar;5(3):87–93. doi: 10.1016/0168-9525(89)90032-2. [DOI] [PubMed] [Google Scholar]
- Deshaies R. J., Koch B. D., Werner-Washburne M., Craig E. A., Schekman R. A subfamily of stress proteins facilitates translocation of secretory and mitochondrial precursor polypeptides. Nature. 1988 Apr 28;332(6167):800–805. doi: 10.1038/332800a0. [DOI] [PubMed] [Google Scholar]
- Deshaies R. J., Sanders S. L., Feldheim D. A., Schekman R. Assembly of yeast Sec proteins involved in translocation into the endoplasmic reticulum into a membrane-bound multisubunit complex. Nature. 1991 Feb 28;349(6312):806–808. doi: 10.1038/349806a0. [DOI] [PubMed] [Google Scholar]
- Geering K., Kraehenbuhl J. P., Rossier B. C. Maturation of the catalytic alpha-subunit of Na,K-ATPase during intracellular transport. J Cell Biol. 1987 Dec;105(6 Pt 1):2613–2619. doi: 10.1083/jcb.105.6.2613. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Green N., Fang H., Walter P. Mutants in three novel complementation groups inhibit membrane protein insertion into and soluble protein translocation across the endoplasmic reticulum membrane of Saccharomyces cerevisiae. J Cell Biol. 1992 Feb;116(3):597–604. doi: 10.1083/jcb.116.3.597. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hann B. C., Poritz M. A., Walter P. Saccharomyces cerevisiae and Schizosaccharomyces pombe contain a homologue to the 54-kD subunit of the signal recognition particle that in S. cerevisiae is essential for growth. J Cell Biol. 1989 Dec;109(6 Pt 2):3223–3230. doi: 10.1083/jcb.109.6.3223. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hann B. C., Stirling C. J., Walter P. SEC65 gene product is a subunit of the yeast signal recognition particle required for its integrity. Nature. 1992 Apr 9;356(6369):532–533. doi: 10.1038/356532a0. [DOI] [PubMed] [Google Scholar]
- Hann B. C., Walter P. The signal recognition particle in S. cerevisiae. Cell. 1991 Oct 4;67(1):131–144. doi: 10.1016/0092-8674(91)90577-l. [DOI] [PubMed] [Google Scholar]
- Hartmann E., Rapoport T. A., Lodish H. F. Predicting the orientation of eukaryotic membrane-spanning proteins. Proc Natl Acad Sci U S A. 1989 Aug;86(15):5786–5790. doi: 10.1073/pnas.86.15.5786. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Holcomb C. L., Hansen W. J., Etcheverry T., Schekman R. Secretory vesicles externalize the major plasma membrane ATPase in yeast. J Cell Biol. 1988 Mar;106(3):641–648. doi: 10.1083/jcb.106.3.641. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hurtley S. M., Helenius A. Protein oligomerization in the endoplasmic reticulum. Annu Rev Cell Biol. 1989;5:277–307. doi: 10.1146/annurev.cb.05.110189.001425. [DOI] [PubMed] [Google Scholar]
- Ljungdahl P. O., Gimeno C. J., Styles C. A., Fink G. R. SHR3: a novel component of the secretory pathway specifically required for localization of amino acid permeases in yeast. Cell. 1992 Oct 30;71(3):463–478. doi: 10.1016/0092-8674(92)90515-e. [DOI] [PubMed] [Google Scholar]
- Nakamoto R. K., Rao R., Slayman C. W. Expression of the yeast plasma membrane [H+]ATPase in secretory vesicles. A new strategy for directed mutagenesis. J Biol Chem. 1991 Apr 25;266(12):7940–7949. [PubMed] [Google Scholar]
- Nguyen T. H., Law D. T., Williams D. B. Binding protein BiP is required for translocation of secretory proteins into the endoplasmic reticulum in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A. 1991 Feb 15;88(4):1565–1569. doi: 10.1073/pnas.88.4.1565. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Normington K., Kohno K., Kozutsumi Y., Gething M. J., Sambrook J. S. cerevisiae encodes an essential protein homologous in sequence and function to mammalian BiP. Cell. 1989 Jun 30;57(7):1223–1236. doi: 10.1016/0092-8674(89)90059-7. [DOI] [PubMed] [Google Scholar]
- Novick P., Schekman R. Export of major cell surface proteins is blocked in yeast secretory mutants. J Cell Biol. 1983 Feb;96(2):541–547. doi: 10.1083/jcb.96.2.541. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pelham H. R. Control of protein exit from the endoplasmic reticulum. Annu Rev Cell Biol. 1989;5:1–23. doi: 10.1146/annurev.cb.05.110189.000245. [DOI] [PubMed] [Google Scholar]
- Perlin D. S., Brown C. L. Identification of structurally distinct catalytic intermediates of the H+-ATPase from yeast plasma membranes. J Biol Chem. 1987 May 15;262(14):6788–6794. [PubMed] [Google Scholar]
- Rao R., Slayman C. W. Mutagenesis of conserved residues in the phosphorylation domain of the yeast plasma membrane H(+)-ATPase. Effects on structure and function. J Biol Chem. 1993 Mar 25;268(9):6708–6713. [PubMed] [Google Scholar]
- Roberts C. J., Pohlig G., Rothman J. H., Stevens T. H. Structure, biosynthesis, and localization of dipeptidyl aminopeptidase B, an integral membrane glycoprotein of the yeast vacuole. J Cell Biol. 1989 Apr;108(4):1363–1373. doi: 10.1083/jcb.108.4.1363. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rose M. D., Misra L. M., Vogel J. P. KAR2, a karyogamy gene, is the yeast homolog of the mammalian BiP/GRP78 gene. Cell. 1989 Jun 30;57(7):1211–1221. doi: 10.1016/0092-8674(89)90058-5. [DOI] [PubMed] [Google Scholar]
- Serrano R., Kielland-Brandt M. C., Fink G. R. Yeast plasma membrane ATPase is essential for growth and has homology with (Na+ + K+), K+- and Ca2+-ATPases. Nature. 1986 Feb 20;319(6055):689–693. doi: 10.1038/319689a0. [DOI] [PubMed] [Google Scholar]
- Simon S. M., Blobel G. A protein-conducting channel in the endoplasmic reticulum. Cell. 1991 May 3;65(3):371–380. doi: 10.1016/0092-8674(91)90455-8. [DOI] [PubMed] [Google Scholar]
- Stevens T., Esmon B., Schekman R. Early stages in the yeast secretory pathway are required for transport of carboxypeptidase Y to the vacuole. Cell. 1982 Sep;30(2):439–448. doi: 10.1016/0092-8674(82)90241-0. [DOI] [PubMed] [Google Scholar]
- Stirling C. J., Hewitt E. W. The S. cerevisiae SEC65 gene encodes a component of yeast signal recognition particle with homology to human SRP19. Nature. 1992 Apr 9;356(6369):534–537. doi: 10.1038/356534a0. [DOI] [PubMed] [Google Scholar]
- Stirling C. J., Rothblatt J., Hosobuchi M., Deshaies R., Schekman R. Protein translocation mutants defective in the insertion of integral membrane proteins into the endoplasmic reticulum. Mol Biol Cell. 1992 Feb;3(2):129–142. doi: 10.1091/mbc.3.2.129. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vogel J. P., Misra L. M., Rose M. D. Loss of BiP/GRP78 function blocks translocation of secretory proteins in yeast. J Cell Biol. 1990 Jun;110(6):1885–1895. doi: 10.1083/jcb.110.6.1885. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Walter P., Lingappa V. R. Mechanism of protein translocation across the endoplasmic reticulum membrane. Annu Rev Cell Biol. 1986;2:499–516. doi: 10.1146/annurev.cb.02.110186.002435. [DOI] [PubMed] [Google Scholar]
- Yu J., Fischman D. A., Steck T. L. Selective solubilization of proteins and phospholipids from red blood cell membranes by nonionic detergents. J Supramol Struct. 1973;1(3):233–248. doi: 10.1002/jss.400010308. [DOI] [PubMed] [Google Scholar]