Genomes and Genes
Gene Symbol: SSC1
Description: Hsp70 family ATPase SSC1
Alias: ENS1, Hsp70 family ATPase SSC1
Species: Saccharomyces cerevisiae S288c
- Frazier A, Dudek J, Guiard B, Voos W, Li Y, Lind M, et al. Pam16 has an essential role in the mitochondrial protein import motor. Nat Struct Mol Biol. 2004;11:226-33 pubmed..Thus, Pam16 is a newly identified type of motor subunit and is required to promote a functional PAM reaction cycle, thereby driving preprotein import into the matrix. ..
- Schiller D, Cheng Y, Liu Q, Walter W, Craig E. Residues of Tim44 involved in both association with the translocon of the inner mitochondrial membrane and regulation of mitochondrial Hsp70 tethering. Mol Cell Biol. 2008;28:4424-33 pubmed publisher..Our results support the idea that Tim44 plays multiple roles in mitochondrial protein import by recruiting Ssc1 and its J protein cochaperone to the translocon and coordinating their interactions to promote efficient protein ..
- Schilke B, Forster J, Davis J, James P, Walter W, Laloraya S, et al. The cold sensitivity of a mutant of Saccharomyces cerevisiae lacking a mitochondrial heat shock protein 70 is suppressed by loss of mitochondrial DNA. J Cell Biol. 1996;134:603-13 pubmed..The matrix of the mitochondria contains another hsp70, Ssc1, which is essential for growth and required for translocation of proteins into mitochondria...
- Nakai M, Kato Y, Ikeda E, Toh e A, Endo T. Yge1p, a eukaryotic Grp-E homolog, is localized in the mitochondrial matrix and interacts with mitochondrial Hsp70. Biochem Biophys Res Commun. 1994;200:435-42 pubmed..caused hypersensitivity to temperature for cell growth, suggesting a genetic interaction between the YGE1 and SSC1 genes...
- Kronidou N, Oppliger W, Bolliger L, Hannavy K, Glick B, Schatz G, et al. Dynamic interaction between Isp45 and mitochondrial hsp70 in the protein import system of the yeast mitochondrial inner membrane. Proc Natl Acad Sci U S A. 1994;91:12818-22 pubmed..This arrangement is reminiscent of the protein transport systems of the yeast endoplasmic reticulum and the bacterial plasma membrane. ..
- Rassow J, Maarse A, Krainer E, Kubrich M, Muller H, Meijer M, et al. Mitochondrial protein import: biochemical and genetic evidence for interaction of matrix hsp70 and the inner membrane protein MIM44. J Cell Biol. 1994;127:1547-56 pubmed..By binding to MIM44, mt-hsp70 is recruited at the protein import sites of the inner membrane, and preproteins arriving at MIM44 may be directly handed over to mt-hsp70. ..
- Blamowska M, Sichting M, Mapa K, Mokranjac D, Neupert W, Hell K. ATPase domain and interdomain linker play a key role in aggregation of mitochondrial Hsp70 chaperone Ssc1. J Biol Chem. 2010;285:4423-31 pubmed publisher..We have analyzed the interaction of Hep1 with mitochondrial Hsp70 (Ssc1) and the determinants in Ssc1 that make it prone to aggregation...
- Sinha D, Joshi N, Chittoor B, Samji P, D Silva P. Role of Magmas in protein transport and human mitochondria biogenesis. Hum Mol Genet. 2010;19:1248-62 pubmed publisher..Together, we propose a model showing how Magmas:DnaJC19 subcomplex is associated with TIM23 complex and thus regulates mitochondrial import process. ..
- Schneider H, Berthold J, Bauer M, Dietmeier K, Guiard B, Brunner M, et al. Mitochondrial Hsp70/MIM44 complex facilitates protein import. Nature. 1994;371:768-74 pubmed..The complex appears to act as a molecular ratchet which is energetically driven by the hydrolysis of ATP. ..
- Becker D, Krayl M, Strub A, Li Y, Mayer M, Voos W. Impaired interdomain communication in mitochondrial Hsp70 results in the loss of inward-directed translocation force. J Biol Chem. 2009;284:2934-46 pubmed publisher..We conclude that even a partial disruption of the interdomain communication in the mtHsp70 chaperone results in an almost complete breakdown of its translocation-driving properties. ..
- Yamamoto H, Momose T, Yatsukawa Y, Ohshima C, Ishikawa D, Sato T, et al. Identification of a novel member of yeast mitochondrial Hsp70-associated motor and chaperone proteins that facilitates protein translocation across the inner membrane. FEBS Lett. 2005;579:507-11 pubmed..Overexpression of the 15-kD protein rescued the functional defects of mtHsp70 in ssc1-3 cells, and a fusion protein containing the 15-kD protein physically interacts with purified mtHsp70...
- Strub A, Rottgers K, Voos W. The Hsp70 peptide-binding domain determines the interaction of the ATPase domain with Tim44 in mitochondria. EMBO J. 2002;21:2626-35 pubmedb>Ssc1, a molecular chaperone of the Hsp70 family, drives preprotein import into the mitochondrial matrix by a specific interaction with the translocase component Tim44...
- Truscott K, Voos W, Frazier A, Lind M, Li Y, Geissler A, et al. A J-protein is an essential subunit of the presequence translocase-associated protein import motor of mitochondria. J Cell Biol. 2003;163:707-13 pubmed..We conclude that the reaction cycle of the PAM of mitochondria involves an essential J-protein. ..
- van der Laan M, Chacinska A, Lind M, Perschil I, Sickmann A, Meyer H, et al. Pam17 is required for architecture and translocation activity of the mitochondrial protein import motor. Mol Cell Biol. 2005;25:7449-58 pubmed..Our findings suggest that Pam17 is required for the correct organization of the Pam16-Pam18 complex and thus contributes to regulation of mtHsp70 activity at the inner membrane translocation site. ..
- Sanjuán Szklarz L, Guiard B, Rissler M, Wiedemann N, Kozjak V, van der Laan M, et al. Inactivation of the mitochondrial heat shock protein zim17 leads to aggregation of matrix hsp70s followed by pleiotropic effects on morphology and protein biogenesis. J Mol Biol. 2005;351:206-18 pubmed
- Moro F, Okamoto K, Donzeau M, Neupert W, Brunner M. Mitochondrial protein import: molecular basis of the ATP-dependent interaction of MtHsp70 with Tim44. J Biol Chem. 2002;277:6874-80 pubmed
- Voos W, Gambill B, Laloraya S, Ang D, Craig E, Pfanner N. Mitochondrial GrpE is present in a complex with hsp70 and preproteins in transit across membranes. Mol Cell Biol. 1994;14:6627-34 pubmed..After being imported into the matrix, the preprotein could be coprecipitated only by antibodies against mt-hsp70. We propose that mt-hsp70 and MGE cooperate in membrane translocation of preproteins. ..
- Laloraya S, Dekker P, Voos W, Craig E, Pfanner N. Mitochondrial GrpE modulates the function of matrix Hsp70 in translocation and maturation of preproteins. Mol Cell Biol. 1995;15:7098-105 pubmed..We conclude that the interaction of Mge1p with mt-Hsp70 promotes the progress of the Hsp70 reaction cycle, which is essential for import and maturation of mitochondrial proteins. ..
- Lutz T, Westermann B, Neupert W, Herrmann J. The mitochondrial proteins Ssq1 and Jac1 are required for the assembly of iron sulfur clusters in mitochondria. J Mol Biol. 2001;307:815-25 pubmedMitochondria of the yeast Saccharomyces cerevisiae contain three different Hsp70 chaperones, Ssc1, Ecm10 and Ssq1...
- Herrmann J, Stuart R, Craig E, Neupert W. Mitochondrial heat shock protein 70, a molecular chaperone for proteins encoded by mitochondrial DNA. J Cell Biol. 1994;127:893-902 pubmed..Thus mt-Hsp70 by acting as a chaperone for proteins encoded by the mitochondrial DNA, has a critical role in the assembly of supra-molecular complexes. ..
- Momose T, Ohshima C, Maeda M, Endo T. Structural basis of functional cooperation of Tim15/Zim17 with yeast mitochondrial Hsp70. EMBO Rep. 2007;8:664-70 pubmed..Therefore, the function of Tim15 in yeast cell growth is well correlated with its ability to suppress mtHsp70 aggregation, although it is still unknown whether inhibition of mtHsp70 aggregation is the primary function of Tim15. ..
- Westermann B, Gaume B, Herrmann J, Neupert W, Schwarz E. Role of the mitochondrial DnaJ homolog Mdj1p as a chaperone for mitochondrially synthesized and imported proteins. Mol Cell Biol. 1996;16:7063-71 pubmed..Our results suggest that Mdj1p together with mt-Hsp70 plays an important role as a chaperone for mitochondrially synthesized polypeptide chains emerging from the ribosome and for translocating proteins at a late import step. ..
- von Ahsen O, Voos W, Henninger H, Pfanner N. The mitochondrial protein import machinery. Role of ATP in dissociation of the Hsp70.Mim44 complex. J Biol Chem. 1995;270:29848-53 pubmed..We conclude that binding of ATP, not hydrolysis, is required to dissociate the mt-Hsp70.Mim44 complex and that the reaction cycle includes an ATP-induced conformational change of mt-Hsp70. ..
- Horst M, Oppliger W, Rospert S, Schönfeld H, Schatz G, Azem A. Sequential action of two hsp70 complexes during protein import into mitochondria. EMBO J. 1997;16:1842-9 pubmed..A precursor protein entering the matrix interacts first with the import complex and then with the folding complex. A chaperone can thus function as part of two different complexes within the same organelle. ..
- Sakuragi S, Liu Q, Craig E. Interaction between the nucleotide exchange factor Mge1 and the mitochondrial Hsp70 Ssc1. J Biol Chem. 1999;274:11275-82 pubmedFunction of Hsp70s such as DnaK of the Escherichia coli cytoplasm and Ssc1 of the mitochondrial matrix of Saccharomyces cerevisiae requires the nucleotide release factors, GrpE and Mge1, respectively...
- Voisine C, Craig E, Zufall N, von Ahsen O, Pfanner N, Voos W. The protein import motor of mitochondria: unfolding and trapping of preproteins are distinct and separable functions of matrix Hsp70. Cell. 1999;97:565-74 pubmed..The motor function of mtHsp70 cannot be explained by passive trapping alone but includes an essential ATP-dependent interaction with Tim44 to generate a pulling force and unfold preproteins. ..
- Voos W, Gambill B, Guiard B, Pfanner N, Craig E. Presequence and mature part of preproteins strongly influence the dependence of mitochondrial protein import on heat shock protein 70 in the matrix. J Cell Biol. 1993;123:119-26 pubmed
- Voisine C, Schilke B, Ohlson M, Beinert H, Marszalek J, Craig E. Role of the mitochondrial Hsp70s, Ssc1 and Ssq1, in the maturation of Yfh1. Mol Cell Biol. 2000;20:3677-84 pubmedThe mitochondrial matrix of the yeast Saccharomyces cerevisiae contains two molecular chaperones of the Hsp70 class, Ssc1 and Ssq1...
- Liu Q, D Silva P, Walter W, Marszalek J, Craig E. Regulated cycling of mitochondrial Hsp70 at the protein import channel. Science. 2003;300:139-41 pubmed..Consistent with the ratchet model of translocation, subsequent hydrolysis of ATP would trap the polypeptide, driving import by preventing its movement back toward the cytosol. ..
- Schmitt M, Neupert W, Langer T. Hsp78, a Clp homologue within mitochondria, can substitute for chaperone functions of mt-hsp70. EMBO J. 1995;14:3434-44 pubmed..of HSP78 does not cause any detectable changes in wild type cells, but results in a petite phenotype in the ssc1-3 mutant strain carrying a temperature-sensitive allele of mt-hsp70...
- Fontanesi F, SOTO I, Horn D, Barrientos A. Mss51 and Ssc1 facilitate translational regulation of cytochrome c oxidase biogenesis. Mol Cell Biol. 2010;30:245-59 pubmed publisher..Notably, the mitochondrial Hsp70 chaperone Ssc1 is shown to be an Mss51 partner throughout its metabolic cycle...
- Voos W, von Ahsen O, Muller H, Guiard B, Rassow J, Pfanner N. Differential requirement for the mitochondrial Hsp70-Tim44 complex in unfolding and translocation of preproteins. EMBO J. 1996;15:2668-77 pubmed..One mutant mtHsp70 (Ssc1-2p) efficiently bound preproteins, but did not show a detectable complex formation with Tim44; the mitochondria ..
- Slutsky Leiderman O, Marom M, Iosefson O, Levy R, Maoz S, Azem A. The interplay between components of the mitochondrial protein translocation motor studied using purified components. J Biol Chem. 2007;282:33935-42 pubmed..Thus, mutually exclusive interactions between various components of the motor with mHsp70 regulate its functional cycle. The results are discussed in light of known models for the function of the mitochondrial translocation motor. ..
- Miao B, Davis J, Craig E. Mge1 functions as a nucleotide release factor for Ssc1, a mitochondrial Hsp70 of Saccharomyces cerevisiae. J Mol Biol. 1997;265:541-52 pubmed..The effect of Mge1 on nucleotide release from Ssc1, an Hsp70 of the mitochondrial matrix, was analyzed...
- D Silva P, Liu Q, Walter W, Craig E. Regulated interactions of mtHsp70 with Tim44 at the translocon in the mitochondrial inner membrane. Nat Struct Mol Biol. 2004;11:1084-91 pubmed..Translocation is driven by the import motor, having at its core the essential chaperone mtHsp70 (Ssc1 in yeast)...
- Merlin A, von Ahsen O, Craig E, Dietmeier K, Pfanner N. A mutant form of mitochondrial GrpE suppresses the sorting defect caused by an alteration in the presequence of cytochrome b2. J Mol Biol. 1997;273:1-6 pubmed
- Sikor M, Mapa K, von Voithenberg L, Mokranjac D, Lamb D. Real-time observation of the conformational dynamics of mitochondrial Hsp70 by spFRET. EMBO J. 2013;32:1639-49 pubmed publisher..Here, we used Förster resonance energy transfer to study the conformational dynamics of individual molecules of Ssc1, a mitochondrial Hsp70, in real time...
- Chacinska A, Lind M, Frazier A, Dudek J, Meisinger C, Geissler A, et al. Mitochondrial presequence translocase: switching between TOM tethering and motor recruitment involves Tim21 and Tim17. Cell. 2005;120:817-29 pubmed..Thus, the presequence translocase is not a static complex but switches between TOM tethering and PAM binding in a reaction cycle involving Tim21 and Tim17. ..
- Archer S, Shirokikh N, Hallwirth C, Beilharz T, Preiss T. Probing the closed-loop model of mRNA translation in living cells. RNA Biol. 2015;12:248-54 pubmed publisher..We observed mRNA-specific variation in the extent of closed-loop formation, consistent with a role for polysome topology in the control of gene expression. ..
- Moriel Carretero M, Tous C, Aguilera A. Control of the function of the transcription and repair factor TFIIH by the action of the cochaperone Ydj1. Proc Natl Acad Sci U S A. 2011;108:15300-5 pubmed publisher..Our results provide evidence for a role of chaperones in NER and transcription, with implications in cancer and TFIIH-associated syndromes. ..
- Chen X, Wang X, Kaufman B, Butow R. Aconitase couples metabolic regulation to mitochondrial DNA maintenance. Science. 2005;307:714-7 pubmed..When constitutively expressed, Aco1p can replace the mtDNA packaging function of the high-mobility-group protein Abf2p. Thus, Aco1p may integrate metabolic signals and mtDNA maintenance. ..
- Krimmer T, Rassow J, Kunau W, Voos W, Pfanner N. Mitochondrial protein import motor: the ATPase domain of matrix Hsp70 is crucial for binding to Tim44, while the peptide binding domain and the carboxy-terminal segment play a stimulatory role. Mol Cell Biol. 2000;20:5879-87 pubmed..We conclude that the ATPase domain of mtHsp70 is essential for and directly interacts with Tim44, clearly separating the mtHsp70-Tim44 interaction from the mtHsp70-substrate interaction. ..
- Chacinska A, Rehling P, Guiard B, Frazier A, Schulze Specking A, Pfanner N, et al. Mitochondrial translocation contact sites: separation of dynamic and stabilizing elements in formation of a TOM-TIM-preprotein supercomplex. EMBO J. 2003;22:5370-81 pubmed..Thus, Tim50 functions as a dynamic factor and the IMS domain of Tom22 represents a stabilizing element in formation of a productive translocation contact site supercomplex. ..
- Ma C, Wu S, Li N, Chen Y, Yan K, Li Z, et al. Structural snapshot of cytoplasmic pre-60S ribosomal particles bound by Nmd3, Lsg1, Tif6 and Reh1. Nat Struct Mol Biol. 2017;24:214-220 pubmed publisher..These findings pinpoint a structural checkpoint role for Nmd3 in PTC assembly, and provide information about functional and mechanistic roles of these assembly factors in the maturation of the 60S ribosomal subunit. ..
- Marada A, Allu P, Murari A, Pullareddy B, Tammineni P, Thiriveedi V, et al. Mge1, a nucleotide exchange factor of Hsp70, acts as an oxidative sensor to regulate mitochondrial Hsp70 function. Mol Biol Cell. 2013;24:692-703 pubmed publisher..This novel oxidative sensor capability of yeast Mge1 might represent an evolutionarily conserved function, given that human recombinant dimeric Mge1 is also sensitive to H2O2...
- Marom M, Dayan D, Demishtein Zohary K, Mokranjac D, Neupert W, Azem A. Direct interaction of mitochondrial targeting presequences with purified components of the TIM23 protein complex. J Biol Chem. 2011;286:43809-15 pubmed publisher..On the basis of our results, we suggest a mechanism of translocation where stronger interactions of the presequences on the trans side of the channel support the import of precursor proteins through TIM23 into the matrix. ..
- Blamowska M, Neupert W, Hell K. Biogenesis of the mitochondrial Hsp70 chaperone. J Cell Biol. 2012;199:125-35 pubmed publisher..Binding of an adenine nucleotide triggered release of Hep1 and folding of the intermediate into native mtHsp70. Thus, Hep1 acts as a specialized chaperone mediating the de novo folding of an Hsp70 chaperone. ..
- Lewrenz I, Rietzschel N, Guiard B, Lill R, van der Laan M, Voos W. The functional interaction of mitochondrial Hsp70s with the escort protein Zim17 is critical for Fe/S biogenesis and substrate interaction at the inner membrane preprotein translocase. J Biol Chem. 2013;288:30931-43 pubmed publisher..In contrast, under respiring conditions, the mitochondrial Hsp70s Ssc1 and Ssq1 exhibited only a partial aggregation...
- Schmidt S, Strub A, Rottgers K, Zufall N, Voos W. The two mitochondrial heat shock proteins 70, Ssc1 and Ssq1, compete for the cochaperone Mge1. J Mol Biol. 2001;313:13-26 pubmedTwo members of the heat shock protein 70 kDa (Hsp70) family, Ssc1 and Ssq1, perform important functions in the mitochondrial matrix...
- Geissler A, Rassow J, Pfanner N, Voos W. Mitochondrial import driving forces: enhanced trapping by matrix Hsp70 stimulates translocation and reduces the membrane potential dependence of loosely folded preproteins. Mol Cell Biol. 2001;21:7097-104 pubmed..We have analyzed a mutant mtHsp70, Ssc1-2, that shows a reduced interaction with the membrane anchor Tim44, but an enhanced trapping of preproteins...
- Merlin A, Voos W, Maarse A, Meijer M, Pfanner N, Rassow J. The J-related segment of tim44 is essential for cell viability: a mutant Tim44 remains in the mitochondrial import site, but inefficiently recruits mtHsp70 and impairs protein translocation. J Cell Biol. 1999;145:961-72 pubmed..The efficient cooperation of mtHsp70 with Tim44 facilitates the translocation of loosely folded preproteins and plays a crucial role in the import of preproteins which contain a tightly folded domain. ..
- Markov D, Savkina M, Anikin M, Del Campo M, Ecker K, Lambowitz A, et al. Identification of proteins associated with the yeast mitochondrial RNA polymerase by tandem affinity purification. Yeast. 2009;26:423-40 pubmed publisher..Further, we found that Mss116p inhibits transcription by mtRNAP in vitro in a steady-state reaction. Our results support the hypothesis that Mss116p and Pet127p are involved in modulation of mtRNAP activity. ..
- Bolliger L, Deloche O, Glick B, Georgopoulos C, Jeno P, Kronidou N, et al. A mitochondrial homolog of bacterial GrpE interacts with mitochondrial hsp70 and is essential for viability. EMBO J. 1994;13:1998-2006 pubmed..Yeast GrpEp is made as a precursor that is cleaved upon import into isolated mitochondria. GrpEp is essential for viability. We suggest that this protein interacts with mhsp70 in a manner analogous to that of GrpE with DnaK of E.coli. ..
- Flom G, Lemieszek M, Fortunato E, Johnson J. Farnesylation of Ydj1 is required for in vivo interaction with Hsp90 client proteins. Mol Biol Cell. 2008;19:5249-58 pubmed publisher..Our results indicate that farnesylation is a major factor contributing to the specific requirement for Ydj1 in promoting proper regulation and activation of diverse Hsp90 clients. ..
- Böttinger L, Guiard B, Oeljeklaus S, Kulawiak B, Zufall N, Wiedemann N, et al. A complex of Cox4 and mitochondrial Hsp70 plays an important role in the assembly of the cytochrome c oxidase. Mol Biol Cell. 2013;24:2609-19 pubmed publisher..Cox4 arrests at this chaperone complex in the absence of mature complex IV. Thus the mtHsp70-Cox4 complex likely serves as a novel delivery system to channel Cox4 into the assembly line when needed. ..
- Schulz C, Rehling P. Remodelling of the active presequence translocase drives motor-dependent mitochondrial protein translocation. Nat Commun. 2014;5:4349 pubmed publisher..Thus, a replenishment cycle of co-chaperones at the TIM23 complex is an integral part of Hsp70's ATPase cycle at the channel exit site and essential to maintain motor-driven mitochondrial protein import. ..
- Bareth B, Nikolov M, Lorenzi I, Hildenbeutel M, Mick D, Helbig C, et al. Oms1 associates with cytochrome c oxidase assembly intermediates to stabilize newly synthesized Cox1. Mol Biol Cell. 2016;27:1570-80 pubmed publisher..Our analyses show that Oms1 participates in cytochrome c oxidase assembly by stabilizing newly synthesized Cox1. ..
- Schiller D. Pam17 and Tim44 act sequentially in protein import into the mitochondrial matrix. Int J Biochem Cell Biol. 2009;41:2343-9 pubmed publisher..Pam17 is involved in an early stage of protein translocation whereas Tim44 assists in a later step of transport, suggesting that both proteins can cooperate in a complementary manner in protein import. ..
- Moro F, Sirrenberg C, Schneider H, Neupert W, Brunner M. The TIM17.23 preprotein translocase of mitochondria: composition and function in protein transport into the matrix. EMBO J. 1999;18:3667-75 pubmed..Tim44 forms dimers which recruit two molecules of mt-Hsp70 to the sites of protein import. A sequential, hand-over-hand mode of interaction of these two mt-Hsp70.Tim44 complexes with a translocating polypeptide chain is proposed. ..