title: Hsp70 targets a cytoplasmic quality control substrate to the San1p ubiquitin ligase.
abstract: Accumulation of misfolded proteins in cellular compartments can result in stress-induced cell death. In the endoplasmic reticulum (ER), ER-associated degradation clears aberrant proteins from the secretory pathway. In the cytoplasm and nucleus, this job is left to the cytoplasmic quality control (CytoQC) machinery. Both processes utilize chaperones and the ubiquitin-proteasome system to aid in protein elimination. Previous studies in yeast have drawn comparisons between these processes using data from structurally and topologically different substrates. We sought to draw a direct comparison between ERAD and CytoQC by studying the elimination of a single misfolded domain that, depending on its residence, is disposed by either of these pathways. The truncated, second nucleotide binding domain (NBD2*) from a yeast ERAD substrate, Ste6p*, resides at the cytoplasmic face of the ER. We show that a soluble form of NBD2* is cytoplasmic and unlike wild-type NBD2 is targeted for proteasome-mediated degradation. In contrast to Ste6p*, which employs the ER-localized Doa10p ubiquitin ligase, NBD2* is ubiquitinated by a nuclear E3 ligase San1p, a factor that is also required for its degradation. Although the yeast cytoplasmic Hsp70 chaperone, Ssa1p, has been thought to facilitate the nuclear import or to maintain the solubility of most CytoQC substrates, we discovered that Ssa1p facilitates the interaction between San1p and NBD2*, demonstrating that chaperones can aid in substrate recognition and San1p-dependent protein degradation. These results emphasize the diverse action of molecular chaperones during CytoQC.
authors: Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
authors: Christopher J
authors: CJ
authors: Guerriero
authors: Kurt F
authors: KF
authors: Weiberth
authors: Jeffrey L
authors: JL
authors: Brodsky
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D021581:Active Transport, Cell Nucleus; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D060746:Endoplasmic Reticulum-Associated Degradation; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D009154:Mutation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D025801:Ubiquitin / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D000074405:Valosin Containing Protein
chemical_list: D018528:ATP-Binding Cassette Transporters; D018797:Cell Cycle Proteins; D018840:HSP70 Heat-Shock Proteins; C489277:STE6 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D025801:Ubiquitin; C500396:SAN1 protein, S cerevisiae; C091362:SSM4 protein, S cerevisiae; C066066:UBR1 protein, S cerevisiae; D044767:Ubiquitin-Protein Ligases; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases; C095973:SSA1 protein, S cerevisiae; C000614177:CDC48 protein, S cerevisiae; D000074405:Valosin Containing Protein
keywords: Cdc48; E3 Ubiquitin Ligase; ERAD; Hsp40; Hsp70; Molecular Chaperone; Proteasome; Ssa1p; Ubiquitin
references: Mol Biol Cell. 1994 Nov;5(11):1185-98
references: 7865884
references: Methods Mol Med. 2002;70:257-65
references: 11917528
references: Nature. 2008 Aug 28;454(7208):1088-95
references: 18756251
references: Annu Rev Genet. 1984;18:233-70
references: 6397123
references: Biotechniques. 1999 Apr;26(4):680-2
references: 10343905
references: J Biol Chem. 2005 Dec 2;280(48):40282-92
references: 16192271
references: EMBO J. 1989 Dec 20;8(13):3973-84
references: 2686977
references: Mol Biol Cell. 2001 Oct;12(10):3226-41
references: 11598205
references: Proc Natl Acad Sci U S A. 2000 Aug 15;97(17):9701-5
references: 10920207
references: Genetics. 1982 Apr;100(4):547-63
references: 6749598
references: Elife. 2013 Jan 22;2:e00308
references: 23358411
references: Nature. 2001 Dec 6;414(6864):652-6
references: 11740563
references: EMBO J. 2002 Feb 15;21(4):615-21
references: 11847109
references: Mol Biol Cell. 2007 Jan;18(1):153-65
references: 17065559
references: J Biol Chem. 2011 Aug 19;286(33):29376-29387
references: 21708947
references: Mol Biol Cell. 2010 Jul 1;21(13):2117-27
references: 20462951
references: Nat Cell Biol. 2002 Feb;4(2):134-9
references: 11813000
references: Science. 1986 Oct 10;234(4773):179-86
references: 3018930
references: J Biol Chem. 2004 Sep 10;279(37):38369-78
references: 15252059
references: Mol Biol Cell. 2004 Nov;15(11):4787-97
references: 15342786
references: Cell. 2004 Jul 9;118(1):99-110
references: 15242647
references: Nat Cell Biol. 2011 Oct 09;13(11):1344-52
references: 21983566
references: Physiol Rev. 2012 Apr;92(2):537-76
references: 22535891
references: Cell. 2012 Nov 21;151(5):1042-54
references: 23178123
references: J Cell Biol. 1993 Dec;123(6 Pt 1):1355-63
references: 8253836
references: J Biol Chem. 2008 Nov 21;283(47):32302-16
references: 18812321
references: Mol Cell Biol. 1996 Aug;16(8):4378-86
references: 8754838
references: Mol Biol Cell. 1992 Feb;3(2):129-42
references: 1550957
references: Nat Cell Biol. 2005 Oct;7(10):993-8
references: 16179953
references: EMBO J. 2006 Feb 8;25(3):533-43
references: 16437165
references: J Cell Biol. 2012 Jun 11;197(6):761-73
references: 22689655
references: Cell. 1992 Apr 17;69(2):353-65
references: 1568250
references: Mol Cell Biol. 1998 Feb;18(2):779-89
references: 9447974
references: Nat Cell Biol. 2012 Feb 02;14(2):117-23
references: 22298039
references: Gene. 1995 Apr 14;156(1):119-22
references: 7737504
references: J Biol Chem. 2013 Mar 1;288(9):6130-9
references: 23335508
references: J Biol Chem. 2012 Jul 6;287(28):23911-22
references: 22593585
references: J Biol Chem. 2004 May 21;279(21):21992-2001
references: 15028727
references: Mol Biol Cell. 2002 Aug;13(8):2760-70
references: 12181344
references: Mol Cell. 2010 Apr 23;38(2):265-79
references: 20417604
references: Proc Natl Acad Sci U S A. 2010 Jan 19;107(3):1106-11
references: 20080635
references: Curr Opin Cell Biol. 2012 Aug;24(4):460-6
references: 22854296
references: Nat Cell Biol. 2001 Jan;3(1):24-9
references: 11146622
references: FEBS J. 2012 Feb;279(4):532-42
references: 22177318
references: Genes Dev. 2001 Oct 15;15(20):2660-74
references: 11641273
references: Curr Biol. 2002 May 14;12(10):R366-71
references: 12015140
references: J Cell Biol. 1996 Feb;132(3):291-8
references: 8636208
references: Curr Opin Cell Biol. 2011 Apr;23(2):167-75
references: 21144725
references: Proc Natl Acad Sci U S A. 2005 Sep 13;102(37):13135-40
references: 16141322
references: Nat Rev Mol Cell Biol. 2008 Dec;9(12):944-57
references: 19002207
references: Cell. 2001 Nov 30;107(5):667-77
references: 11733065
references: Proc Natl Acad Sci U S A. 2011 Oct 11;108(41):17004-9
references: 21953697
references: Mol Biol Cell. 2010 May 1;21(9):1439-48
references: 20237159
references: Protein Sci. 2006 Mar;15(3):647-54
references: 16501229
references: Mol Biol Cell. 2011 Jul 1;22(13):2384-95
references: 21551067
references: J Biol Chem. 1999 Feb 5;274(6):3453-60
references: 9920890
references: Cell. 1991 Jan 11;64(1):13-5
references: 1986863
references: Trends Biochem Sci. 2010 Feb;35(2):74-82
references: 19853458
references: Mol Biol Cell. 2000 Oct;11(10):3425-39
references: 11029046
references: EMBO J. 1991 Dec;10(12):3777-85
references: 1935899
references: Cell Stress Chaperones. 2007 Spring;12(1):1-8
references: 17441502
references: EMBO Rep. 2000 Sep;1(3):225-31
references: 11256604
references: Mol Cell Biol. 2002 Jan;22(2):626-34
references: 11756557
references: Annu Rev Biochem. 2012;81:261-89
references: 22524314
references: Nat Chem Biol. 2007 Jun;3(6):331-8
references: 17486044
references: J Histochem Cytochem. 2003 Apr;51(4):545-8
references: 12642634
references: Nature. 2010 Sep 23;467(7314):470-3
references: 20835226
references: Biochem Biophys Res Commun. 2010 Jan 15;391(3):1449-54
references: 20034470
references: Trends Cell Biol. 2012 Jan;22(1):22-32
references: 22055166
references: Biochim Biophys Acta. 2012 Jan;1823(1):117-24
references: 21945179
references: EMBO Rep. 2004 Jul;5(7):692-7
references: 15167887
references: Science. 1999 Aug 6;285(5429):901-6
references: 10436161
references: Mol Cell Biol. 1996 Sep;16(9):4773-81
references: 8756635
references: Cell. 1995 Sep 22;82(6):885-93
references: 7553849
references: Antioxid Redox Signal. 2012 May 15;16(10):1119-28
references: 22229892
references: J Cell Biol. 2006 Feb 27;172(5):719-31
references: 16505167
references: Cell. 2006 Dec 29;127(7):1401-13
references: 17190603
references: Proc Natl Acad Sci U S A. 2006 Jul 25;103(30):11178-83
references: 16847254
references: Methods Mol Biol. 2005;301:3-22
references: 15917622
references: PLoS One. 2013;8(1):e52099
references: 23341891
references: Cell. 2005 Jun 3;121(5):739-48
references: 15935760
references: Mol Biol Cell. 2009 Feb;20(3):1006-19
references: 19073890
references: Biochem Biophys Res Commun. 2012 Aug 31;425(3):689-95
references: 22842567
references: J Cell Biol. 1998 Dec 28;143(7):1883-98
references: 9864362
references: Cell. 2008 Jan 11;132(1):101-12
references: 18191224
references: J Biochem. 1990 Nov;108(5):846-51
references: 2081737
references: Cell. 2005 Mar 25;120(6):803-15
references: 15797381
references: J Cell Biol. 2001 May 28;153(5):1061-70
references: 11381090
references: J Biol Chem. 2008 Mar 14;283(11):7166-75
references: 18174173
references: J Cell Biol. 2004 Apr;165(1):41-52
references: 15078901
references: Biochem Biophys Res Commun. 2010 Jan 1;391(1):1056-61
references: 19995551
references: J Biol Chem. 2004 Jun 25;279(26):26830-8
references: 15078868
references: J Biol Chem. 2007 Nov 9;282(45):32665-75
references: 17823116
references: Mol Biol Cell. 1998 Oct;9(10):2767-84
references: 9763443
references: Mol Biol Cell. 2010 Jul 1;21(13):2102-16
references: 20462952
references: Biochim Biophys Acta. 2010 Jun;1803(6):684-93
references: 19891995
references: J Biol Chem. 1996 Nov 1;271(44):27280-4
references: 8910302