![]() |
|
|
A more recent version of this article appeared on January 1, 2007
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Submitted on April 21, 2006
Revised on October 13, 2006
Accepted on October 17, 2006
*Institut fuer Biochemie, Universitaet Stuttgart, 70569 Stuttgart, Germany;
Department of Microbiology and Immunology, University of California, San Francisco, CA 94143
Monitoring Editor: Randy Schekman
The mechanism of protein quality control and elimination of misfolded proteins in the cytoplasm is poorly understood. We studied the involvement of cytoplasmic factors required for degradation of two ER-import defective mutated derivatives of carboxypeptidase yscY (
ssCPY* and
ssCPY*-GFP) and also examined the requirements for degradation of the corresponding wild type enzyme made ER-import incompetent by removal of its signal sequence (
ssCPY). All these protein species are rapidly degraded via the ubiquitin-proteasome system. Degradation requires the ubiquitin conjugating enzymes Ubc4p and Ubc5p, the cytoplasmic Hsp70 Ssa chaperone machinery and the Hsp70 cochaperone Ydj1p. Neither the Hsp90 chaperones nor Hsp104 or the small heat shock proteins Hsp26 and Hsp42 are involved in the degradation process. Elimination of a GFP fusion (GFP-cODC), containing the C-terminal 37 amino acids of ornithine decarboxylase (cODC) directing this enzyme to the proteasome, is independent of Ssa1p function. Fusion of
ssCPY* to GFP-cODC to form
ssCPY*-GFP-cODC reimposes a dependency on the Ssa1p chaperone for degradation. Evidently, the misfolded protein domain dictates the route of protein elimination. These data and our further results give evidence that the Ssa1p-Ydj1p machinery recognizes misfolded protein domains, keeps misfolded proteins soluble, solubilizes precipitated protein material and escorts and delivers misfolded proteins in the ubiquitinated state to the proteasome for degradation.
Present address: Center for Cancer Research, National Cancer Institute, Frederick, MD 21702.
Address correspondence to:
Dieter H. Wolf (dieter.wolf{at}ibc.uni-stuttgart.de)
This article has been cited by other articles:
![]() |
J. W. Heck, S. K. Cheung, and R. Y. Hampton Cytoplasmic protein quality control degradation mediated by parallel actions of the E3 ubiquitin ligases Ubr1 and San1 PNAS, January 19, 2010; 107(3): 1106 - 1111. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. S. Vembar, Y. Jin, J. L. Brodsky, and L. M. Hendershot The Mammalian Hsp40 ERdj3 Requires Its Hsp70 Interaction and Substrate-binding Properties to Complement Various Yeast Hsp40-dependent Functions J. Biol. Chem., November 20, 2009; 284(47): 32462 - 32471. [Abstract] [Full Text] [PDF] |
||||
![]() |
U. von Plehwe, U. Berndt, C. Conz, M. Chiabudini, E. Fitzke, A. Sickmann, A. Petersen, D. Pfeifer, and S. Rospert The Hsp70 homolog Ssb is essential for glucose sensing via the SNF1 kinase network Genes & Dev., September 1, 2009; 23(17): 2102 - 2115. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Belville, J.-D. Marechal, S. Pennetier, P. Carmillo, L. Masgrau, L. Messika-Zeitoun, J. Galey, G. Machado, D. Treton, J. Gonzales, et al. Natural mutations of the anti-Mullerian hormone type II receptor found in persistent Mullerian duct syndrome affect ligand binding, signal transduction and cellular transport Hum. Mol. Genet., August 15, 2009; 18(16): 3002 - 3013. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. B. Metzger, M. J. Maurer, B. M. Dancy, and S. Michaelis Degradation of a Cytosolic Protein Requires Endoplasmic Reticulum-associated Degradation Machinery J. Biol. Chem., November 21, 2008; 283(47): 32302 - 32316. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. A. Spooner, P. J. Hart, J. P. Cook, P. Pietroni, C. Rogon, J. Hohfeld, L. M. Roberts, and J. M. Lord Cytosolic chaperones influence the fate of a toxin dislocated from the endoplasmic reticulum PNAS, November 11, 2008; 105(45): 17408 - 17413. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. K. Mandal, N. B. Nillegoda, J. A. Chen, and A. J. Caplan Ydj1 Protects Nascent Protein Kinases from Degradation and Controls the Rate of Their Maturation Mol. Cell. Biol., July 1, 2008; 28(13): 4434 - 4444. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. L. Hrizo, V. Gusarova, D. M. Habiel, J. L. Goeckeler, E. A. Fisher, and J. L. Brodsky The Hsp110 Molecular Chaperone Stabilizes Apolipoprotein B from Endoplasmic Reticulum-associated Degradation (ERAD) J. Biol. Chem., November 9, 2007; 282(45): 32665 - 32675. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Pagant, L. Kung, M. Dorrington, M. C.S. Lee, and E. A. Miller Inhibiting Endoplasmic Reticulum (ER)-associated Degradation of Misfolded Yor1p Does Not Permit ER Export Despite the Presence of a Diacidic Sorting Signal Mol. Biol. Cell, September 1, 2007; 18(9): 3398 - 3413. [Abstract] [Full Text] [PDF] |
||||