Gene Symbol: SBA1
Description: Hsp90 cochaperone SBA1
Alias: CST18, Hsp90 cochaperone SBA1
Species: Saccharomyces cerevisiae S288c

Top Publications

  1. 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. ..
  2. Siligardi G, Hu B, Panaretou B, Piper P, Pearl L, Prodromou C. Co-chaperone regulation of conformational switching in the Hsp90 ATPase cycle. J Biol Chem. 2004;279:51989-98 pubmed
    ..calorimetry and difference circular dichroism) and ATPase regulation by the co-chaperones Aha1, Sti1 (Hop), and Sba1 (p23)...
  3. Richter K, Walter S, Buchner J. The Co-chaperone Sba1 connects the ATPase reaction of Hsp90 to the progression of the chaperone cycle. J Mol Biol. 2004;342:1403-13 pubmed
    ..During this process, Hsp90 was found to associate transiently with several accessory factors, such as p23/Sba1, Hop/Sti1, and prolyl isomerases...
  4. Ali M, Roe S, Vaughan C, Meyer P, Panaretou B, Piper P, et al. Crystal structure of an Hsp90-nucleotide-p23/Sba1 closed chaperone complex. Nature. 2006;440:1013-7 pubmed
    ..present the crystal structure of full-length yeast Hsp90 in complex with an ATP analogue and the co-chaperone p23/Sba1. The structure reveals the complex architecture of the 'closed' state of the Hsp90 chaperone, the extensive ..
  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
    The Saccharomyces cerevisiae SBA1 gene was cloned by PCR amplification from yeast genomic DNA following its identification as encoding an ortholog of human p23, an Hsp90 cochaperone...
  6. 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. ..
  7. 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
  8. Obermann W, Sondermann H, Russo A, Pavletich N, Hartl F. In vivo function of Hsp90 is dependent on ATP binding and ATP hydrolysis. J Cell Biol. 1998;143:901-10 pubmed
    ..Our results establish Hsp90 as an ATP-dependent chaperone. ..
  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. Finally, we show that Cns1 functions in MAP kinase signaling in association with Cpr7. ..

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. Zierer B, Rübbelke M, Tippel F, Madl T, Schopf F, Rutz D, et al. Importance of cycle timing for the function of the molecular chaperone Hsp90. Nat Struct Mol Biol. 2016;23:1020-1028 pubmed publisher
    ..Thus, the timing of conformational transitions is crucial for Hsp90 function and not cycle speed. ..
  3. Armstrong H, Wolmarans A, Mercier R, Mai B, LaPointe P. The co-chaperone Hch1 regulates Hsp90 function differently than its homologue Aha1 and confers sensitivity to yeast to the Hsp90 inhibitor NVP-AUY922. PLoS ONE. 2012;7:e49322 pubmed publisher
    ..We further conclude that Hch1p plays a critical role in regulating Hsp90 inhibitor drug sensitivity in yeast. ..
  4. Forafonov F, Toogun O, Grad I, Suslova E, Freeman B, Picard D. p23/Sba1p protects against Hsp90 inhibitors independently of its intrinsic chaperone activity. Mol Cell Biol. 2008;28:3446-56 pubmed publisher
    ..The SBA1 gene that encodes the p23 ortholog in this species is not an essential gene...
  5. 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
    ..the "early-stage" Hsp90 complex, and was absent from "late-stage" Hsp90 complexes characterized by the presence of Sba1/p23...
  6. Zelin E, Zhang Y, Toogun O, Zhong S, Freeman B. The p23 molecular chaperone and GCN5 acetylase jointly modulate protein-DNA dynamics and open chromatin status. Mol Cell. 2012;48:459-70 pubmed publisher
    ..Our data support a model in which p23 and GCN5 regulate diverse multistep pathways by controlling the longevity of protein-DNA complexes. ..
  7. 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
  8. Ratzke C, Hellenkamp B, Hugel T. Four-colour FRET reveals directionality in the Hsp90 multicomponent machinery. Nat Commun. 2014;5:4192 pubmed publisher
  9. Zuehlke A, Johnson J. Chaperoning the chaperone: a role for the co-chaperone Cpr7 in modulating Hsp90 function in Saccharomyces cerevisiae. Genetics. 2012;191:805-14 pubmed publisher
    ..Hsp90 undergoes a complex series of conformational changes and interacts with partner co-chaperones such as Sba1, Cpr6, Cpr7, and Cns1 as it binds and hydrolyzes ATP...
  10. Lancaster D, Dobson C, Rachubinski R. Chaperone proteins select and maintain [PIN+] prion conformations in Saccharomyces cerevisiae. J Biol Chem. 2013;288:1266-76 pubmed publisher
    ..Together, our results demonstrate a role for chaperones in regulating the prion variant complement of a cell. ..
  11. Daturpalli S, Knieß R, Lee C, Mayer M. Large Rotation of the N-terminal Domain of Hsp90 Is Important for Interaction with Some but Not All Client Proteins. J Mol Biol. 2017;429:1406-1423 pubmed publisher
    ..domain of Hsp90 rotates by approximately 180° as compared to the crystal structure of yeast Hsp90 in complex with Sba1 and AMPPNP...
  12. 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
    ..However, overexpression of SBA1, PPT1, AHA1 or HCH1 caused varying levels of growth defects in an sgt1-K360E strain...
  13. Toogun O, Zeiger W, Freeman B. The p23 molecular chaperone promotes functional telomerase complexes through DNA dissociation. Proc Natl Acad Sci U S A. 2007;104:5765-70 pubmed
    ..Notably, telomere occupancy by telomerase and the extension rate of a shortened telomere fluctuated with changing Sba1 protein levels in vivo...
  14. 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
    ..These results suggest a novel role for Hsp90 in the essential cellular functions of transcription and DNA repair. ..
  15. Echtenkamp F, Gvozdenov Z, Adkins N, Zhang Y, Lynch Day M, Watanabe S, et al. Hsp90 and p23 Molecular Chaperones Control Chromatin Architecture by Maintaining the Functional Pool of the RSC Chromatin Remodeler. Mol Cell. 2016;64:888-899 pubmed publisher
    ..In the case of RSC, p23 and Hsp90 promote a dynamic action, allowing a limited number of remodelers to effectively maintain chromatin in a pliable state. ..
  16. Knoblauch R, Garabedian M. Role for Hsp90-associated cochaperone p23 in estrogen receptor signal transduction. Mol Cell Biol. 1999;19:3748-59 pubmed
    ..Together, these results strongly suggest that p23 plays an important role in ER signal transduction. ..