SSE1/YPL106C Summary Help

SSE1 BASIC INFORMATION

Standard Name SSE1
Systematic Name YPL106C
Alias LPG3 , MSI3
Feature Type ORF, Verified
Description ATPase that is a component of the heat shock protein Hsp90 chaperone complex; binds unfolded proteins; member of the heat shock protein 70 (HSP70) family; localized to the cytoplasm (1, 2, 3 and see Summary Paragraph)
GO Annotations All SSE1 GO evidence and references
    View Computational GO annotations for SSE1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
High-throughput
Mutant Phenotype All SSE1 Phenotype details and references
Classical genetics
null
overexpression
reduction of function
Large-scale survey
null
overexpression
Interactions SSE1 All interactions details and references
224 total interaction(s) for 113 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 146
  • Affinity Capture-RNA: 1
  • Affinity Capture-Western: 11
  • Biochemical Activity: 5
  • Co-crystal Structure: 2
  • Co-fractionation: 3
  • Co-purification: 1
  • Reconstituted Complex: 6
  • Two-hybrid: 1
Genetic Interactions
  • Dosage Growth Defect: 2
  • Dosage Lethality: 3
  • Dosage Rescue: 14
  • Phenotypic Enhancement: 2
  • Phenotypic Suppression: 2
  • Synthetic Growth Defect: 13
  • Synthetic Lethality: 11
  • Synthetic Rescue: 1
Sequence Information
ChrXVI:352272 to 350191 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gbrowse
Last Update Coordinates: 2004-07-21 | Sequence: 1996-07-31
Subfeature details
Relative
Coordinates		 Chromosomal
Coordinates		 Most Recent Updates
Coordinates Sequence
CDS 1..2082 352272..350191 2004-07-21 1996-07-31
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | UniProtKB
Primary SGDIDS000006027

SSE1 RESOURCES

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  • Functional Analysis

Click on histogram for expression summary
Expression Summary histogram

ADDITIONAL INFORMATION for SSE1

SUMMARY PARAGRAPH for SSE1

SSE1 and SSE2 encode chaperonins that are in the Hsp110 subclass of HSP70 proteins (4). HSP70 is a large family of proteins that has been evolutionarily conserved from bacteria (DnaK) to humans (HSP72/73). HSP70 proteins were originally classified based upon their induction by heat shock and their size of ~70kDa. The main function of these proteins is to serve as molecular chaperones, binding newly-translated proteins to assist in proper folding and prevent aggregation/misfolding (reviewed in 5 and 6). SSE1 and SSE2 are two of nine cytosolic forms of HSP70 found in S. cerevisiae (SSA1, SSA2, SSA3, SSA4, SSB1, SSB2, SSE1, SSE2, SSZ1).

SSE is the yeast homolog of mammlian HSP110; the SSE/HSP110 subclass is only found in eukaryotic cells. It appears that the main function of these proteins is to act as nucleotide exchange factors (NEF) for HSP70 chaperones during protein refolding (7, 8). Additionally, independent of their NEF activity, these proteins can bind unfolded peptides and act as a 'holdase', maintaining their substrates in a folding-competent state by preventing misfolding/aggregation (reviewed in 9). Sse protein function has also been implicated in PKA signaling and HSP90 chaperone complex activity (10, 1).

SSE1 and SSE2 are 76% identical to each other and share 70% similarity with the HSP70 subfamily SSA (4). Like all other Hsp70 proteins, Sse1p and Sse2p contain an N-terminal ATPase domain and a C-terminal peptide-binding domain, but unlike other HSP70s, these domains have been shown to function and interact in trans (3). ATPase activity of Sse1p is stimulated by the DnaJ/HSP40 co-chaperone Sis1p (11). The Sse ATPase domain is also required for Sse1p to interact with Ssa1p and Ssb1p (7). Expression of SSE1 and SSE2 is induced by heat shock via the transcriptional activator Hsf1p, which binds to a heat shock element in the SSE gene promoter (4, 1). Deletion of SSE1 derepresses Hsf1p activity and also decreases cell growth rate, while sse2 null mutations have no discernable phenotype, and loss of both gene products results in lethality (1, 3, 4).

Last updated: 2006-11-21

REFERENCES CITED ON THIS PAGE [View Complete Literature Guide for SSE1]

1) Liu XD, et al.  (1999) The yeast Hsp110 family member, Sse1, is an Hsp90 cochaperone. J Biol Chem 274(38):26654-60
2) Goeckeler JL, et al.  (2002) Overexpression of yeast Hsp110 homolog Sse1p suppresses ydj1-151 thermosensitivity and restores Hsp90-dependent activity. Mol Biol Cell 13(8):2760-70
3) Shaner L, et al.  (2004) The function of the yeast molecular chaperone Sse1 is mechanistically distinct from the closely related hsp70 family. J Biol Chem 279(21):21992-2001
4) Mukai H, et al.  (1993) Isolation and characterization of SSE1 and SSE2, new members of the yeast HSP70 multigene family. Gene 132(1):57-66
5) Bukau B and Horwich AL  (1998) The Hsp70 and Hsp60 chaperone machines. Cell 92(3):351-66
6) Becker J and Craig EA  (1994) Heat-shock proteins as molecular chaperones. Eur J Biochem 219(1-2):11-23
7) Shaner L, et al.  (2005) The yeast Hsp110 Sse1 functionally interacts with the Hsp70 chaperones Ssa and Ssb. J Biol Chem 280(50):41262-9
8) Dragovic Z, et al.  (2006) Molecular chaperones of the Hsp110 family act as nucleotide exchange factors of Hsp70s. EMBO J 25(11):2519-28
9) Easton DP, et al.  (2000) The hsp110 and Grp1 70 stress proteins: newly recognized relatives of the Hsp70s. Cell Stress Chaperones 5(4):276-90
10) Trott A, et al.  (2005) The molecular chaperone Sse1 and the growth control protein kinase Sch9 collaborate to regulate protein kinase A activity in Saccharomyces cerevisiae. Genetics 170(3):1009-21
11) Raviol H, et al.  (2006) Human and yeast Hsp110 chaperones exhibit functional differences. FEBS Lett 580(1):168-74