J. Cell Biol.
© The Rockefeller University Press
0021-9525/97/01/299/08 $2.00
Volume 136, Number 2, January 27, 1997 299-306

A Heterodimer of Thioredoxin and I^B₂ Cooperates with Sec18p (NSF) to Promote Yeast Vacuole Inheritance

Zuoyu Xu, Andreas Mayer, Eric Muller,^* and William Wickner

Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755-3844; and ^* Department of Biochemistry, University of Washington, Seattle, Washington 98195

Early in S phase, the vacuole (lysosome) of Saccharomyces cerevisiae projects a stream of vesicles and membranous tubules into the bud where they fuse and establish the daughter vacuole. This inheritance reaction can be studied in vitro with isolated vacuoles. Rapid and efficient homotypic fusion between saltwashed vacuoles requires the addition of only two purified soluble proteins, Sec18p (NSF) and LMA1, a novel heterodimer with a thioredoxin subunit. We now report the identity of the second subunit of LMA1 as I^B₂, a previously identified cytosolic inhibitor of vacuolar proteinase B. Both subunits are needed for efficient vacuole inheritance in vivo and for the LMA1 activity in cell extracts. Each subunit acts via a novel mechanism, as the thioredoxin subunit is not acting through redox chemistry and LMA1 is still needed for the fusion of vacuoles which do not contain proteinase B. Both Sec18p and LMA1 act at an early stage of the in vitro reaction. Though LMA1 does not stimulate Sec18p-mediated Sec17p release, LMA1 cannot fulfill its function before Sec18p. Upon Sec17p/Sec18p action, vacuoles become labile but are rapidly stabilized by LMA1. The action of LMA1 and Sec18p is thus coupled and ordered. These data establish LMA1 as a novel factor in trafficking of yeast vacuoles.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Geumann, U., Barysch, S. V., Hoopmann, P., Jahn, R., Rizzoli, S. O. (2008). SNARE Function Is Not Involved in Early Endosome Docking. Mol. Biol. Cell 19: 5327-5337 [Abstract] [Full Text]  
• Kamena, F., Diefenbacher, M., Kilchert, C., Schwarz, H., Spang, A. (2008). Ypt1p is essential for retrograde Golgi-ER transport and for Golgi maintenance in S. cerevisiae. J. Cell Sci. 121: 1293-1302 [Abstract] [Full Text]  
• Decker, B. L., Wickner, W. T. (2006). Enolase Activates Homotypic Vacuole Fusion and Protein Transport to the Vacuole in Yeast. J. Biol. Chem. 281: 14523-14528 [Abstract] [Full Text]  
• Ballew, N., Liu, Y., Barlowe, C. (2005). A Rab Requirement Is Not Bypassed in SLY1-20 Suppression. Mol. Biol. Cell 16: 1839-1849 [Abstract] [Full Text]  
• Whalley, T., Timmers, K., Coorssen, J., Bezrukov, L., Kingsley, D. H., Zimmerberg, J. (2004). Membrane fusion of secretory vesicles of the sea urchin egg in the absence of NSF. J. Cell Sci. 117: 2345-2356 [Abstract] [Full Text]  
• Alexander, S., Srinivasan, S., Alexander, H. (2003). Proteomics Opens Doors to the Mechanisms of Developmentally Regulated Secretion. Mol. Cell. Proteomics 2: 1156-1163 [Abstract] [Full Text]  
• Marash, M., Gerst, J. E. (2003). Phosphorylation of the Autoinhibitory Domain of the Sso t-SNAREs Promotes Binding of the Vsm1 SNARE Regulator in Yeast. Mol. Biol. Cell 14: 3114-3125 [Abstract] [Full Text]  
• Bayer, M. J., Reese, C., Buhler, S., Peters, C., Mayer, A. (2003). Vacuole membrane fusion: V0 functions after trans-SNARE pairing and is coupled to the Ca2+-releasing channel. JCB 162: 211-222 [Abstract] [Full Text]  
• Seeley, E. S., Kato, M., Margolis, N., Wickner, W., Eitzen, G. (2002). Genomic Analysis of Homotypic Vacuole Fusion. Mol. Biol. Cell 13: 782-794 [Abstract] [Full Text]  
• Spang, A., Herrmann, J. M., Hamamoto, S., Schekman, R. (2001). The ADP Ribosylation Factor-Nucleotide Exchange Factors Gea1p and Gea2p Have Overlapping, but Not Redundant Functions in Retrograde Transport from the Golgi to the Endoplasmic Reticulum. Mol. Biol. Cell 12: 1035-1045 [Abstract] [Full Text]  
• Seals, D. F., Eitzen, G., Margolis, N., Wickner, W. T., Price, A. (2000). A Ypt/Rab effector complex containing the Sec1 homolog Vps33p is required for homotypic vacuole fusion. Proc. Natl. Acad. Sci. USA 97: 9402-9407 [Abstract] [Full Text]  
• Price, A., Wickner, W., Ungermann, C. (2000). Proteins Needed for Vesicle Budding from the Golgi Complex Are also Required for the Docking Step of Homotypic Vacuole Fusion. JCB 148: 1223-1230 [Abstract] [Full Text]  
• Mayer, A., Scheglmann, D., Dove, S., Glatz, A., Wickner, W., Haas, A. (2000). Phosphatidylinositol 4,5-Bisphosphate Regulates Two Steps of Homotypic Vacuole Fusion. Mol. Biol. Cell 11: 807-817 [Abstract] [Full Text]  
• Murray, J. M., Johnson, D. I. (2000). Isolation and Characterization of Nrf1p, a Novel Negative Regulator of the Cdc42p GTPase in Schizosaccharomyces pombe. Genetics 154: 155-165 [Abstract] [Full Text]  
• Ungermann, C., Wickner, W., Xu, Z. (1999). Vacuole acidification is required for trans-SNARE pairing, LMA1 release, and homotypic fusion. Proc. Natl. Acad. Sci. USA 96: 11194-11199 [Abstract] [Full Text]  
• Peters, C., Andrews, P. D., Stark, M. J., Tadic, S. C., Glatz, A., Podtelejnikov, A., Mann, M., Mayer, A. (1999). Control of the Terminal Step of Intracellular Membrane Fusion by Protein Phosphatase 1 . Science 285: 1084-1087 [Abstract] [Full Text]  
• Coe, J. G. S., Lim, A. C. B., Xu, J., Hong, W. (1999). A Role for Tlg1p in the Transport of Proteins within the Golgi Apparatus of Saccharomyces cerevisiae. Mol. Biol. Cell 10: 2407-2423 [Abstract] [Full Text]  
• Lustgarten, V., Gerst, J. E. (1999). Yeast VSM1 Encodes a v-SNARE Binding Protein That May Act as a Negative Regulator of Constitutive Exocytosis. Mol. Cell. Biol. 19: 4480-4494 [Abstract] [Full Text]  
• Spang, A., Schekman, R. (1998). Reconstitution of Retrograde Transport from the Golgi to the ER In Vitro. JCB 143: 589-599 [Abstract] [Full Text]  
• VanRheenen, S. M., Cao, X., Lupashin, V. V., Barlowe, C., Gerard Waters, M. (1998). Sec35p, a Novel Peripheral Membrane Protein, Is Required for ER to Golgi Vesicle Docking. JCB 141: 1107-1119 [Abstract] [Full Text]  
• Klionsky, D. J. (1998). Nonclassical Protein Sorting to the Yeast Vacuole. J. Biol. Chem. 273: 10807-10810 [Full Text]  
• Wang, Y.-X., Catlett, N. L., Weisman, L. S. (1998). Vac8p, a Vacuolar Protein with Armadillo Repeats, Functions in both Vacuole Inheritance and Protein Targeting from the Cytoplasm to Vacuole. JCB 140: 1063-1074 [Abstract] [Full Text]  
• Bryant, N. J., Stevens, T. H. (1998). Vacuole Biogenesis in Saccharomyces cerevisiae: Protein Transport Pathways to the Yeast Vacuole. Microbiol. Mol. Biol. Rev. 62: 230-247 [Abstract] [Full Text]  
• Ungermann, C., Nichols, B. J., Pelham, H. R.B., Wickner, W. (1998). A Vacuolar v-t-SNARE Complex, the Predominant Form In Vivo and on Isolated Vacuoles, Is Disassembled and Activated for Docking and Fusion. JCB 140: 61-69 [Abstract] [Full Text]  
• Pan, X, Goldfarb, D. (1998). YEB3/VAC8 encodes a myristylated armadillo protein of the Saccharomyces cerevisiae vacuolar membrane that functions in vacuole fusion and inheritance. J. Cell Sci. 111: 2137-2147 [Abstract]  
• Barlowe, C. (1997). Coupled ER to Golgi Transport Reconstituted with Purified Cytosolic Proteins. JCB 139: 1097-1108 [Abstract] [Full Text]  
• Slusarewicz, P., Xu, Z., Seefeld, K., Haas, A., Wickner, W. T. (1997). I2B is a small cytosolic protein that participates in vacuole fusion. Proc. Natl. Acad. Sci. USA 94: 5582-5587 [Abstract] [Full Text]  
• Mayer, A., Wickner, W. (1997). Docking of Yeast Vacuoles Is Catalyzed by the Ras-like GTPase Ypt7p after Symmetric Priming by Sec18p (NSF). JCB 136: 307-317 [Abstract] [Full Text]  
• Legesse-Miller, A., Sagiv, Y., Glozman, R., Elazar, Z. (2000). Aut7p, a Soluble Autophagic Factor, Participates in Multiple Membrane Trafficking Processes. J. Biol. Chem. 275: 32966-32973 [Abstract] [Full Text]  
• Wang, Y.-X., Kauffman, E. J., Duex, J. E., Weisman, L. S. (2001). Fusion of Docked Membranes Requires the Armadillo Repeat Protein Vac8p. J. Biol. Chem. 276: 35133-35140 [Abstract] [Full Text]  

Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents