Gene Symbol: STI1
Description: Hsp90 cochaperone STI1
Alias: Hsp90 cochaperone STI1
Species: Saccharomyces cerevisiae S288c
Products:     STI1

Top Publications

  1. Richter K, Muschler P, Hainzl O, Reinstein J, Buchner J. Sti1 is a non-competitive inhibitor of the Hsp90 ATPase. Binding prevents the N-terminal dimerization reaction during the atpase cycle. J Biol Chem. 2003;278:10328-33 pubmed
    ..During the chaperone cycle, Hsp90 has been found associated with the partner protein Hop/Sti1, which seems to be required for the progression of the cycle. However, little is known about its specific function...
  2. Ren M, Santhanam A, Lee P, Caplan A, Garrett S. Alteration of the protein kinase binding domain enhances function of the Saccharomyces cerevisiae molecular chaperone Cdc37. Eukaryot Cell. 2007;6:1363-72 pubmed
  3. Flom G, Weekes J, Williams J, Johnson J. Effect of mutation of the tetratricopeptide repeat and asparatate-proline 2 domains of Sti1 on Hsp90 signaling and interaction in Saccharomyces cerevisiae. Genetics. 2006;172:41-51 pubmed
    ..interactions with Hsp70 and Hsp90 via separate tetratricopeptide repeat (TPR) domains, the cochaperone protein Hop/Sti1 has been proposed to play a critical role in the transfer of client proteins from Hsp70 to Hsp90...
  4. Duina A, Chang H, Marsh J, Lindquist S, Gaber R. A cyclophilin function in Hsp90-dependent signal transduction. Science. 1996;274:1713-5 pubmed
    ..Deletion of CPR7 caused severe growth defects when combined with mutations that decrease the amount of Hsp90 or Sti1, another component of the Hsp90 chaperone machinery...
  5. Fang Y, Fliss A, Rao J, Caplan A. SBA1 encodes a yeast hsp90 cochaperone that is homologous to vertebrate p23 proteins. Mol Cell Biol. 1998;18:3727-34 pubmed
    ..A double deletion of SBA1 and STI1, encoding an Hsp90 cochaperone, displayed synthetic growth defects...
  6. Mandal A, Gibney P, Nillegoda N, Theodoraki M, Caplan A, Morano K. Hsp110 chaperones control client fate determination in the hsp70-Hsp90 chaperone system. Mol Biol Cell. 2010;21:1439-48 pubmed publisher
    ..These findings support a model in which Hsp110 chaperones contribute significantly to the decision made by Hsp70 to fold or degrade a client protein. ..
  7. Abbas Terki T, Donze O, Briand P, Picard D. Hsp104 interacts with Hsp90 cochaperones in respiring yeast. Mol Cell Biol. 2001;21:7569-75 pubmed
    ..We show that the Hsp90 cochaperones Sti1, Cpr7, and Cns1, which utilize tetratricopeptide repeat (TPR) domains to interact with a common surface on Hsp90, ..
  8. Flom G, Weekes J, Johnson J. Novel interaction of the Hsp90 chaperone machine with Ssl2, an essential DNA helicase in Saccharomyces cerevisiae. Curr Genet. 2005;47:368-80 pubmed
    ..Hsp90 functions with a number of co-chaperone proteins, including Sti1/Hop...
  9. Lee P, Shabbir A, Cardozo C, Caplan A. Sti1 and Cdc37 can stabilize Hsp90 in chaperone complexes with a protein kinase. Mol Biol Cell. 2004;15:1785-92 pubmed
    ..These data suggest that Cdc37 and Sti1 have functional overlap in stabilizing Hsp90:client complexes...

More Information


  1. Johnson J, Halas A, Flom G. Nucleotide-dependent interaction of Saccharomyces cerevisiae Hsp90 with the cochaperone proteins Sti1, Cpr6, and Sba1. Mol Cell Biol. 2007;27:768-76 pubmed
    ..affect Hsp90 interactions with cochaperone proteins, we monitored assembly of wild-type and mutant Hsp90 with Sti1, Sba1, and Cpr6 in Saccharomyces cerevisiae cell extracts...
  2. Reidy M, Masison D. Sti1 regulation of Hsp70 and Hsp90 is critical for curing of Saccharomyces cerevisiae [PSI+] prions by Hsp104. Mol Cell Biol. 2010;30:3542-52 pubmed publisher
    ..Here, we confirm this link by finding that deletion of STI1 both suppresses Ssa1-21 impairment of [PSI(+)] and blocks Hsp104 curing of [PSI(+)]...
  3. Abbas Terki T, Briand P, Donze O, Picard D. The Hsp90 co-chaperones Cdc37 and Sti1 interact physically and genetically. Biol Chem. 2002;383:1335-42 pubmed
    ..b>Sti1 and Cpr7 are non-essential Hsp90 co-chaperones that bind to a common surface on Hsp90 through tetratricopeptide ..
  4. Li J, Richter K, Buchner J. Mixed Hsp90-cochaperone complexes are important for the progression of the reaction cycle. Nat Struct Mol Biol. 2011;18:61-6 pubmed publisher
    ..The first cochaperone entering the cycle is the Hsp90 ATPase inhibitor Sti1 (Hop in human), which later is replaced by a prolyl isomerase (PPIase) and p23...
  5. Liu X, Morano K, Thiele D. The yeast Hsp110 family member, Sse1, is an Hsp90 cochaperone. J Biol Chem. 1999;274:26654-60 pubmed
    ..Disruption of SSE1 along with STI1, encoding an established subunit of the Hsp90 chaperone complex, resulted in a severe synthetic growth phenotype...
  6. Prodromou C, Siligardi G, O Brien R, Woolfson D, Regan L, Panaretou B, et al. Regulation of Hsp90 ATPase activity by tetratricopeptide repeat (TPR)-domain co-chaperones. EMBO J. 1999;18:754-62 pubmed
    ..We have now analysed the interaction of the yeast TPR-domain co-chaperones Sti1 and Cpr6 with yeast Hsp90 by isothermal titration calorimetry, circular dichroism spectroscopy and analytical ..
  7. Siligardi G, Panaretou B, Meyer P, Singh S, Woolfson D, Piper P, et al. Regulation of Hsp90 ATPase activity by the co-chaperone Cdc37p/p50cdc37. J Biol Chem. 2002;277:20151-9 pubmed
    ..For some client proteins the co-chaperone Sti1/Hop/p60 acts as a "scaffold," recruiting Hsp70 and the bound client to Hsp90 early in the cycle and ..
  8. Wegele H, Haslbeck M, Reinstein J, Buchner J. Sti1 is a novel activator of the Ssa proteins. J Biol Chem. 2003;278:25970-6 pubmed
    ..In Saccharomyces cerevisiae two components of the complex, yeast Hsp90 (yHsp90) and Sti1, the yeast homologue of Hop, had already been identified, but it remained to be shown which of the 14 different ..
  9. Marsh J, Kalton H, Gaber R. Cns1 is an essential protein associated with the hsp90 chaperone complex in Saccharomyces cerevisiae that can restore cyclophilin 40-dependent functions in cpr7Delta cells. Mol Cell Biol. 1998;18:7353-9 pubmed
    ..Thus far, Cns1 is the only tetratricopeptide repeat-containing component of Hsp90 heterocomplexes found to be essential for cell viability under all conditions tested. ..
  10. Jones G, Song Y, Chung S, Masison D. Propagation of Saccharomyces cerevisiae [PSI+] prion is impaired by factors that regulate Hsp70 substrate binding. Mol Cell Biol. 2004;24:3928-37 pubmed
    ..Although Cpr7p and Sti1p are Hsp90 cochaperones, we provide evidence that Hsp90 is not involved in [PSI(+)] propagation, suggesting that Sti1p and Cpr7p functionally interact with Hsp70 independently of Hsp90. ..
  11. Chang H, Nathan D, Lindquist S. In vivo analysis of the Hsp90 cochaperone Sti1 (p60). Mol Cell Biol. 1997;17:318-25 pubmed
    Hsp90 interacts with Sti1 (p60) in lysates of yeast and vertebrate cells. Here we provide the first analysis of their interaction in vivo...
  12. Chang H, Lindquist S. Conservation of Hsp90 macromolecular complexes in Saccharomyces cerevisiae. J Biol Chem. 1994;269:24983-8 pubmed
    ..Yeast homologs of Hsp70 (in particular, members of the Ssa subfamily), p60 (Sti1), and a 45-kDa immunophilin homolog were also isolated in this manner, by virtue of their specific, stable ..
  13. Valay J, Simon M, Dubois M, Bensaude O, Facca C, Faye G. The KIN28 gene is required both for RNA polymerase II mediated transcription and phosphorylation of the Rpb1p CTD. J Mol Biol. 1995;249:535-44 pubmed
    ..thermosensitive mutation (kin28-ts3) has uncovered genetic interactions between gene KIN28 and genes RAD3, SIN4, STI1 and CDC37...
  14. Hoseini H, Pandey S, Jores T, Schmitt A, Franz Wachtel M, Macek B, et al. The cytosolic cochaperone Sti1 is relevant for mitochondrial biogenesis and morphology. FEBS J. 2016;283:3338-52 pubmed publisher yeast cells we identified the cytosolic chaperones Hsp70 (Ssa1) and Hsp90 (Hsp82) as well as their cochaperones, Sti1 and Ydj1, as putative cytosolic factors involved in mitochondrial protein import...
  15. Mollapour M, Bourboulia D, Beebe K, Woodford M, Polier S, Hoang A, et al. Asymmetric Hsp90 N domain SUMOylation recruits Aha1 and ATP-competitive inhibitors. Mol Cell. 2014;53:317-29 pubmed publisher
  16. Mayr C, Richter K, Lilie H, Buchner J. Cpr6 and Cpr7, two closely related Hsp90-associated immunophilins from Saccharomyces cerevisiae, differ in their functional properties. J Biol Chem. 2000;275:34140-6 pubmed
    ..In contrast, the chaperone activity of Cpr6 is much lower than that of Cpr7. Based on these results we suggest that the two immunophilins perform overlapping but not identical tasks in the Hsp90 chaperone cycle. ..
  17. Wolfe K, Ren H, Trepte P, Cyr D. The Hsp70/90 cochaperone, Sti1, suppresses proteotoxicity by regulating spatial quality control of amyloid-like proteins. Mol Biol Cell. 2013;24:3588-602 pubmed publisher
    ..Subtle modulation of Sti1 activity reciprocally affects Htt toxicity and the packaging of Htt103Q into foci...
  18. Catlett M, Kaplan K. Sgt1p is a unique co-chaperone that acts as a client adaptor to link Hsp90 to Skp1p. J Biol Chem. 2006;281:33739-48 pubmed
    ..The multidomain nature of Sgt1p and its ability to bridge the interaction between Skp1p and Hsp82p argue that Sgt1p acts as a "client adaptor" recruiting specific clients to Hsp82p co-chaperone complexes. ..
  19. Lee P, Rao J, Fliss A, Yang E, Garrett S, Caplan A. The Cdc37 protein kinase-binding domain is sufficient for protein kinase activity and cell viability. J Cell Biol. 2002;159:1051-9 pubmed
    ..cerevisiae, we show that CDC37 overexpression suppressed a defect in v-Src folding in yeast deleted for STI1, which recruits Hsp90 to misfolded clients...
  20. Lotz G, Lin H, Harst A, Obermann W. Aha1 binds to the middle domain of Hsp90, contributes to client protein activation, and stimulates the ATPase activity of the molecular chaperone. J Biol Chem. 2003;278:17228-35 pubmed
    ..Thus, our results identify a novel type of cofactor involved in the regulation of the molecular chaperone Hsp90. ..
  21. Wolfe K, Ren H, Trepte P, Cyr D. Polyglutamine-rich suppressors of huntingtin toxicity act upstream of Hsp70 and Sti1 in spatial quality control of amyloid-like proteins. PLoS ONE. 2014;9:e95914 pubmed publisher
    ..Protective action of Pop2 and Cbk1 in spatial quality control is dependent upon the Hsp70 co-chaperone Sti1, which packages amyloid-like proteins into benign foci...
  22. Johnson J, Zuehlke A, Tenge V, Langworthy J. Mutation of essential Hsp90 co-chaperones SGT1 or CNS1 renders yeast hypersensitive to overexpression of other co-chaperones. Curr Genet. 2014;60:265-76 pubmed publisher
    ..This provides new evidence that co-chaperones selectively compete for binding to subpopulations of cellular Hsp90 and suggest that changes in the relative levels of co-chaperones may have dramatic effects on Hsp90 function. ..
  23. Mirzaei H, Rogers R, Grimes B, Eng J, Aderem A, Aebersold R. Characterizing the connectivity of poly-ubiquitin chains by selected reaction monitoring mass spectrometry. Mol Biosyst. 2010;6:2004-14 pubmed publisher
    ..cerevisiae. We then applied the method to detect toxin induced changes in the poly-ubiquitination profile in complex and enriched protein samples. ..
  24. Mollapour M, Tsutsumi S, Truman A, Xu W, Vaughan C, Beebe K, et al. Threonine 22 phosphorylation attenuates Hsp90 interaction with cochaperones and affects its chaperone activity. Mol Cell. 2011;41:672-81 pubmed publisher
    ..Overexpression of Aha1 stimulates the ATPase activity, restores cochaperone interactions, and compensates for the functional defects of these Hsp90 mutants. ..
  25. Kiktev D, Patterson J, Muller S, Bariar B, Pan T, Chernoff Y. Regulation of chaperone effects on a yeast prion by cochaperone Sgt2. Mol Cell Biol. 2012;32:4960-70 pubmed publisher
    ..Our data implicate Sgt2 as an amyloid "sensor" and a regulator of chaperone targeting to different types of aggregation-prone proteins. ..
  26. Zuehlke A, Wren N, Tenge V, Johnson J. Interaction of heat shock protein 90 and the co-chaperone Cpr6 with Ura2, a bifunctional enzyme required for pyrimidine biosynthesis. J Biol Chem. 2013;288:27406-14 pubmed publisher
    ..Further analysis suggests that the carboxyl-terminal 100 amino acids of Cpr6 and Cpr7 are critical for specifying their unique functions, providing new information about this important class of Hsp90 co-chaperones. ..
  27. Millson S, Vaughan C, Zhai C, Ali M, Panaretou B, Piper P, et al. Chaperone ligand-discrimination by the TPR-domain protein Tah1. Biochem J. 2008;413:261-8 pubmed publisher
    ..In the present study we also show that Tah1 can affect the ATPase activity of Hsp90, in common with some other TPR-domain proteins. ..
  28. Horvat N, Armstrong H, Lee B, Mercier R, Wolmarans A, Knowles J, et al. A mutation in the catalytic loop of Hsp90 specifically impairs ATPase stimulation by Aha1p, but not Hch1p. J Mol Biol. 2014;426:2379-92 pubmed publisher
    ..Our work here suggests that both Hch1p and Aha1p regulate Hsp90 function through interaction with the catalytic loop but do so in different ways. ..
  29. Lee C, Graf C, Mayer F, Richter S, Mayer M. Dynamics of the regulation of Hsp90 by the co-chaperone Sti1. EMBO J. 2012;31:1518-28 pubmed publisher
    ..clients to Hsp90 requires prior interaction with Hsp70 and a transfer reaction that is mediated by the co-chaperone Sti1/Hop. Sti1 furthers client transfer by inhibiting Hsp90's ATPase activity...
  30. Gomar Alba M, Jimenez Marti E, del Olmo M. The Saccharomyces cerevisiae Hot1p regulated gene YHR087W (HGI1) has a role in translation upon high glucose concentration stress. BMC Mol Biol. 2012;13:19 pubmed publisher
  31. Tenge V, Knowles J, Johnson J. The ribosomal biogenesis protein Utp21 interacts with Hsp90 and has differing requirements for Hsp90-associated proteins. PLoS ONE. 2014;9:e92569 pubmed publisher
  32. Röhl A, Wengler D, Madl T, Lagleder S, Tippel F, Herrmann M, et al. Hsp90 regulates the dynamics of its cochaperone Sti1 and the transfer of Hsp70 between modules. Nat Commun. 2015;6:6655 pubmed publisher
    The cochaperone Sti1/Hop physically links Hsp70 and Hsp90. The protein exhibits one binding site for Hsp90 (TPR2A) and two binding sites for Hsp70 (TPR1 and TPR2B). How these sites are used remained enigmatic...
  33. Jones M, Bachant J, Castillo A, Giddings T, Winey M. Yeast Dam1p is required to maintain spindle integrity during mitosis and interacts with the Mps1p kinase. Mol Biol Cell. 1999;10:2377-91 pubmed
  34. Schmid A, Lagleder S, Gräwert M, Röhl A, Hagn F, Wandinger S, et al. The architecture of functional modules in the Hsp90 co-chaperone Sti1/Hop. EMBO J. 2012;31:1506-17 pubmed publisher
    b>Sti1/Hop is a modular protein required for the transfer of client proteins from the Hsp70 to the Hsp90 chaperone system in eukaryotes. It binds Hsp70 and Hsp90 simultaneously via TPR (tetratricopeptide repeat) domains...
  35. Retzlaff M, Hagn F, Mitschke L, Hessling M, Gugel F, Kessler H, et al. Asymmetric activation of the hsp90 dimer by its cochaperone aha1. Mol Cell. 2010;37:344-54 pubmed publisher
    ..This seems to functionalize the two subunits of the Hsp90 dimer in different ways, in that one subunit can be used for conformational ATPase regulation and the other for substrate protein processing. ..
  36. Mollapour M, Tsutsumi S, Donnelly A, Beebe K, Tokita M, Lee M, et al. Swe1Wee1-dependent tyrosine phosphorylation of Hsp90 regulates distinct facets of chaperone function. Mol Cell. 2010;37:333-43 pubmed publisher
  37. Moosavi B, Wongwigkarn J, Tuite M. Hsp70/Hsp90 co-chaperones are required for efficient Hsp104-mediated elimination of the yeast [PSI(+)] prion but not for prion propagation. Yeast. 2010;27:167-79 pubmed publisher
    ..Neither Sti1p nor Cpr7p is necessary for prion propagation but we show that deletion of the STI1 and CPR7 genes leads to a significant reduction in the generation of [psi(-)] cells by Hsp104 overexpression...
  38. Scherrer T, Mittal N, Janga S, Gerber A. A screen for RNA-binding proteins in yeast indicates dual functions for many enzymes. PLoS ONE. 2010;5:e15499 pubmed publisher
    ..Our results suggest that many proteins may associate with mRNAs and possibly control their fates, providing dense connections between different layers of cellular regulation. ..