Sequestration of essential proteins causes prion associated toxicity in yeast.
Prions are infectious, aggregated proteins that cause diseases in mammals but are not normally toxic in fungi. Excess Sup35p, an essential yeast protein that can exist as the [PSI(+)] prion, inhibits growth of [PSI(+)] but not [psi(-)] cells. This toxicity is rescued by expressing the Sup35Cp domain of Sup35p, which is sufficient for cell viability but not prion propagation. We now show that rescue requires Sup35Cp levels to be proportional to Sup35p overexpression. Overexpression of Sup35p appeared to cause pre-existing [PSI(+)] aggregates to coalesce into larger aggregates, but these were not toxic per se because they formed even when Sup35Cp rescued growth. Overexpression of Sup45p, but not other tested essential Sup35p binding partners, caused rescue. Sup45-GFPp formed puncta that colocalized with large [PSI(+)] Sup35-RFPp aggregates in cells overexpressing Sup35p, and the frequency of the Sup45-GFPp puncta was reduced by rescuing levels of Sup35Cp. In contrast, [PSI(+)] toxicity caused by a high excess of the Sup35p prion domain (Sup35NMp) was rescued by a single copy of Sup35Cp, was not rescued by Sup45p overexpression and was not associated with the appearance of Sup45-GFPp puncta. This suggests [PSI(+)] toxicity caused by excess Sup35p verses Sup35NMp is, respectively, through sequestration/inactivation of Sup45p verses Sup35p.
Vishveshwara
Namitha
N
Department of Biological Sciences, Laboratory for Molecular Biology, University of Illinois at Chicago, Chicago, IL 60607, USA.
Bradley
Michael E
ME
Liebman
Susan W
SW
D018628:Gene Dosage; D050296:Microbial Viability; D010454:Peptide Termination Factors / Q000235:genetics / Q000378:metabolism*; D011328:Prions / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion
D010454:Peptide Termination Factors; D011328:Prions; C068068:SUP35 protein, S cerevisiae; C080775:SUP45 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins
Mol Cell Biol. 1997 May;17(5):2798-805
9111351
Proc Natl Acad Sci U S A. 2002 Dec 10;99 Suppl 4:16392-9
12149514
Genetics. 1996 Dec;144(4):1375-86
8978027
EMBO J. 1999 Mar 1;18(5):1182-91
10064585
Nature. 2002 Jan 10;415(6868):141-7
11805826
Nat Cell Biol. 2005 Nov;7(11):1039-44
16385730
Mol Cell Biol. 2001 Oct;21(20):7035-46
11564886
Nature. 2004 Mar 18;428(6980):323-8
15029196
EMBO J. 2000 May 2;19(9):1942-52
10790361
Nature. 2004 Mar 18;428(6980):319-23
15029195
Proc Natl Acad Sci U S A. 2008 May 20;105(20):7206-11
18480252
Proc Natl Acad Sci U S A. 1998 Mar 3;95(5):2400-5
9482897
Cell. 2006 Jun 16;125(6):1125-36
16777602
N Engl J Med. 2003 Apr 3;348(14):1356-64
12672864
Cell. 1998 Jun 26;93(7):1241-52
9657156
Science. 2001 Mar 23;291(5512):2423-8
11264541
Mol Microbiol. 1993 Mar;7(5):683-92
8469113
Genetics. 1994 Jul;137(3):671-6
8088512
Nature. 2006 Oct 19;443(7113):803-10
17051207
Mol Cell Biol. 2004 Sep;24(17):7769-78
15314182
Mol Biol Cell. 2008 Jun;19(6):2433-43
18353968
Br Med Bull. 2003;66:109-20
14522853
Proc Natl Acad Sci U S A. 1998 Nov 10;95(23):13363-83
9811807
Mol Microbiol. 2001 Jan;39(1):37-46
11123686
Mol Cell Biol. 2006 Jan;26(2):617-29
16382152
Nature. 2004 Oct 14;431(7010):805-10
15483602
Nat Rev Mol Cell Biol. 2007 Feb;8(2):101-12
17245412
Neurobiol Dis. 2006 Sep;23(3):543-51
16766198
Nature. 2005 Jun 9;435(7043):765-72
15944694
EMBO J. 1995 Sep 1;14(17):4365-73
7556078
Genetics. 1991 Jul;128(3):513-20
1874413
Nature. 1995 Jun 22;375(6533):698-700
7791905
PLoS Biol. 2007 Feb;5(2):e24
17253904
Nature. 2008 Aug 28;454(7208):1088-95
18756251
Genetics. 1997 Oct;147(2):507-19
9335589
J Biol Chem. 2004 Dec 3;279(49):51042-8
15465809
Science. 1994 Apr 22;264(5158):566-9
7909170
Annu Rev Microbiol. 2002;56:703-41
12142498
Cell. 1998 May 1;93(3):337-48
9590169
Nature. 2005 Sep 8;437(7056):262-5
16148935
Eur J Neurosci. 2008 Jun;27(11):2803-20
18588526
Cell. 2001 Jul 27;106(2):171-82
11511345
EMBO J. 2007 Aug 22;26(16):3794-803
17673909
Cell. 2000 Feb 4;100(3):311-21
10676813
Science. 2002 Jun 14;296(5575):1991-5
12065827
Nature. 2007 Sep 13;449(7159):233-7
17767153
Proc Natl Acad Sci U S A. 2004 Aug 31;101(35):12934-9
15326312
Mol Cell. 2000 Jan;5(1):163-72
10678178
Genetics. 1989 May;122(1):19-27
2659436
Curr Genet. 1993 Sep;24(3):268-70
8221937
PLoS Biol. 2004 Apr;2(4):E86
15045026
Nat Med. 2004 Jul;10 Suppl:S10-7
15272267
EMBO J. 1996 Jun 17;15(12):3127-34
8670813
Mol Microbiol. 2004 Mar;51(6):1649-59
15009892
Proc Natl Acad Sci U S A. 1999 Feb 16;96(4):1498-503
9990052
EMBO J. 2001 Nov 15;20(22):6236-45
11707395
RNA. 1996 Apr;2(4):334-41
8634914
Science. 1982 Apr 9;216(4542):136-44
6801762
Mol Cell Biol. 2002 Jul;22(13):4723-38
12052880
PLoS Genet. 2009 Feb;5(2):e1000382
19214209
Proc Natl Acad Sci U S A. 1993 Dec 1;90(23):10962-6
7902575
Science. 1996 Aug 2;273(5275):622-6
8662547
RNA. 2000 Sep;6(9):1236-47
10999601
Science. 1995 May 12;268(5212):880-4
7754373
J Biol Chem. 2005 Mar 11;280(10):8808-12
15618222
Proc Natl Acad Sci U S A. 2002 Dec 10;99 Suppl 4:16446-53
12461168
Mol Cell Biol. 2002 May;22(10):3301-15
11971964