TIM44

Summary

Gene Symbol: TIM44
Description: protein translocase subunit TIM44
Alias: ISP45, MIM44, MPI1, protein translocase subunit TIM44
Species: Saccharomyces cerevisiae S288c

Top Publications

  1. D Silva P, Schilke B, Hayashi M, Craig E. Interaction of the J-protein heterodimer Pam18/Pam16 of the mitochondrial import motor with the translocon of the inner membrane. Mol Biol Cell. 2008;19:424-32 pubmed
    ..by alterations in the N terminus of Pam16 were isolated and found to be due to mutations in a short segment of TIM44, the gene encoding the peripheral membrane protein that tethers mtHsp70 to the translocon...
  2. 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
    ..In conclusion, our results suggest that interdomain communication makes Ssc1 prone to aggregation. Hep1 counteracts aggregation by binding to this aggregation-prone conformer. ..
  3. 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
  4. Mokranjac D, Sichting M, Neupert W, Hell K. Tim14, a novel key component of the import motor of the TIM23 protein translocase of mitochondria. EMBO J. 2003;22:4945-56 pubmed
    ..In particular, import of proteins that require the action of mtHsp70 is affected. Tim14 interacts with Tim44 and mtHsp70 in an ATP-dependent manner. A mutation in the HPD motif of the J-domain of Tim14 is lethal...
  5. Dienhart M, Stuart R. The yeast Aac2 protein exists in physical association with the cytochrome bc1-COX supercomplex and the TIM23 machinery. Mol Biol Cell. 2008;19:3934-43 pubmed publisher
    ..The physiological implications of the association of AAC with the cytochrome bc(1)-COX-TIM23 supercomplex are also discussed. ..
  6. Blom J, Dekker P, Meijer M. Functional and physical interactions of components of the yeast mitochondrial inner-membrane import machinery (MIM). Eur J Biochem. 1995;232:309-14 pubmed
    The essential mitochondrial inner-membrane protein, Mim44, is involved in the translocation of preproteins across the mitochondrial inner membrane...
  7. 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
    ..It is well established that an essential peripheral membrane protein, Tim44, tethers mitochondrial Hsp70 (mtHsp70), the core of the import motor, to the translocon...
  8. 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
    ..contains four essential subunits: the matrix heat shock protein 70 (mtHsp70) and its three cochaperones Mge1, Tim44 and Pam18...
  9. 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. ..

More Information

Publications64

  1. 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. ..
  2. Geissler A, Chacinska A, Truscott K, Wiedemann N, Brandner K, Sickmann A, et al. The mitochondrial presequence translocase: an essential role of Tim50 in directing preproteins to the import channel. Cell. 2002;111:507-18 pubmed
    ..Thus, Tim50 is crucial for guiding the precursors of matrix proteins to their insertion site in the inner membrane. ..
  3. Yamamoto H, Esaki M, Kanamori T, Tamura Y, Nishikawa S, Endo T. Tim50 is a subunit of the TIM23 complex that links protein translocation across the outer and inner mitochondrial membranes. Cell. 2002;111:519-28 pubmed
    ..A translocation intermediate accumulated at the TOM complex is crosslinked to Tim50. We suggest that Tim50, in cooperation with Tim23, facilitates transfer of the translocating protein from the TOM complex to the TIM23 complex ..
  4. Kozany C, Mokranjac D, Sichting M, Neupert W, Hell K. The J domain-related cochaperone Tim16 is a constituent of the mitochondrial TIM23 preprotein translocase. Nat Struct Mol Biol. 2004;11:234-41 pubmed
    ..b>Tim44 at the inner face of the translocation pore recruits the chaperone mtHsp70, which binds the incoming precursor ..
  5. 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
    ..Three essential subunits of the motor are known: mitochondrial Hsp70 (mtHsp70); the peripheral membrane protein Tim44; and the nucleotide exchange factor Mge1...
  6. 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. ..
  7. Mokranjac D, Popov Celeketic D, Hell K, Neupert W. Role of Tim21 in mitochondrial translocation contact sites. J Biol Chem. 2005;280:23437-40 pubmed
    ..We propose that Tim21 binds to the trans site of the TOM complex thus keeping the two translocases in close contact. ..
  8. Chacinska A, van der Laan M, Mehnert C, Guiard B, Mick D, Hutu D, et al. Distinct forms of mitochondrial TOM-TIM supercomplexes define signal-dependent states of preprotein sorting. Mol Cell Biol. 2010;30:307-18 pubmed publisher
    ..Depending on the signals of the preproteins, switches between the different forms of supercomplex and TIM23 are required for the completion of preprotein import. ..
  9. Popov Celeketic D, Waegemann K, Mapa K, Neupert W, Mokranjac D. Role of the import motor in insertion of transmembrane segments by the mitochondrial TIM23 complex. EMBO Rep. 2011;12:542-8 pubmed publisher
    ..Furthermore, our results suggest a role for the import motor in lateral insertion. Thus, the import motor is involved in ATP-dependent translocation and ATP-independent lateral insertion. ..
  10. 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
    ..and a conditionally lethal unfolding defect caused by an impaired interaction of mtHsp70 with the membrane anchor Tim44. Even enhanced trapping in wild-type mitochondria does not generate a pulling force...
  11. Mokranjac D, Berg A, Adam A, Neupert W, Hell K. Association of the Tim14.Tim16 subcomplex with the TIM23 translocase is crucial for function of the mitochondrial protein import motor. J Biol Chem. 2007;282:18037-45 pubmed
    ..Deletion of hydrophobic segments in both, Tim16 and Tim14, is lethal. We conclude that import into the matrix space of mitochondria requires association of the co-chaperones Tim16 and Tim14 with the TIM23 preprotein translocase. ..
  12. 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
    ..This molecular chaperone of the mitochondrial matrix is recruited to the protein import machinery by MIM44, a component associated with the inner membrane of the mitochondria...
  13. Hutu D, Guiard B, Chacinska A, Becker D, Pfanner N, Rehling P, et al. Mitochondrial protein import motor: differential role of Tim44 in the recruitment of Pam17 and J-complex to the presequence translocase. Mol Biol Cell. 2008;19:2642-9 pubmed publisher
    ..Activity and localization of mtHsp70 are regulated by four membrane-associated cochaperones: the adaptor protein Tim44, the stimulatory J-complex Pam18/Pam16, and Pam17...
  14. 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
    ..The peripheral inner membrane protein, Tim44, recruits mtHsp70 in an ATP-dependent manner to the import sites...
  15. 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
    ..b>Tim44, a peripheral inner-membrane protein, tethers it to the import channel...
  16. Tamura Y, Harada Y, Yamano K, Watanabe K, Ishikawa D, Ohshima C, et al. Identification of Tam41 maintaining integrity of the TIM23 protein translocator complex in mitochondria. J Cell Biol. 2006;174:631-7 pubmed
    ..These results suggest that Tam41 facilitates mitochondrial protein import by maintaining the functional integrity of the TIM23 protein translocator complex from the matrix side of the inner membrane. ..
  17. 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 pubmed
    ..In contrast to Ssc1, Ssq1 does not associate with the Tim44 subunit of the protein translocating complex, indicating a different function of both chaperones...
  18. Maarse A, Blom J, Grivell L, Meijer M. MPI1, an essential gene encoding a mitochondrial membrane protein, is possibly involved in protein import into yeast mitochondria. EMBO J. 1992;11:3619-28 pubmed
    ..We have cloned and sequenced a gene, termed MPI1, that can rescue the genetic defect of one group of these mutants. MPI1 encodes a hydrophilic 48...
  19. Pareek G, Krishnamoorthy V, D Silva P. Molecular insights revealing interaction of Tim23 and channel subunits of presequence translocase. Mol Cell Biol. 2013;33:4641-59 pubmed publisher
    ..Our model conceptually explains the cooperative function between Tam41 and Pam17 subunits, while the antagonistic activity of Tim21 predominantly determines the bound and free forms of the PAM subcomplex during import. ..
  20. 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
    ..We show that one of the membrane proteins, Isp45, spans the mitochondrial inner membrane yet is extracted from this membrane at high pH...
  21. Mokranjac D, Bourenkov G, Hell K, Neupert W, Groll M. Structure and function of Tim14 and Tim16, the J and J-like components of the mitochondrial protein import motor. EMBO J. 2006;25:4675-85 pubmed
    ..The first crystal structure of a J domain in complex with a regulatory protein provides new insights into the function of the mitochondrial TIM23 translocase and the Hsp70 chaperone system in general. ..
  22. 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
    ..Two of these preprotein-binding proteins are the peripheral inner membrane protein MIM44 and the matrix heat shock protein hsp70...
  23. Popov Celeketic D, Mapa K, Neupert W, Mokranjac D. Active remodelling of the TIM23 complex during translocation of preproteins into mitochondria. EMBO J. 2008;27:1469-80 pubmed publisher
    ..Our data demonstrate that the TIM23 complex acts as a single structural and functional entity that is actively remodelled to sort preproteins into different mitochondrial subcompartments. ..
  24. Ryan K, Leung R, Jensen R. Characterization of the mitochondrial inner membrane translocase complex: the Tim23p hydrophobic domain interacts with Tim17p but not with other Tim23p molecules. Mol Cell Biol. 1998;18:178-87 pubmed
    ..In contrast, Tim23Cp cannot be coimmunoprecipitated with Tim23p, raising the possibility that the hydrophobic domain of Tim23p does not interact with other Tim23 molecules. ..
  25. 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
    ..Binding of mt-Hsp70 to the protein Mim44 of the inner membrane import site seems to be an essential part of an ATP-dependent reaction cycle...
  26. 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
    ..different presequences with purified soluble domains of yeast Tim50 (Tim50IMS), Tim23 (Tim23IMS), and full-length Tim44 was examined...
  27. Bömer U, Meijer M, Maarse A, Hönlinger A, Dekker P, Pfanner N, et al. Multiple interactions of components mediating preprotein translocation across the inner mitochondrial membrane. EMBO J. 1997;16:2205-16 pubmed
    ..Tim17 and Tim23 are thought to build a preprotein translocation channel, while Tim44 transiently interacts with the matrix heat shock protein Hsp70 to form an ATP-driven import motor...
  28. 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
    ..PAM are known: the preprotein-binding matrix heat shock protein 70 (mtHsp70), the nucleotide exchange factor Mge1, Tim44 that directs mtHsp70 to the inner membrane, and the membrane-bound complex of Pam16-Pam18 that regulates the ..
  29. Demishtein Zohary K, Marom M, Neupert W, Mokranjac D, Azem A. GxxxG motifs hold the TIM23 complex together. FEBS J. 2015;282:2178-86 pubmed publisher
    ..We conclude that the GxxxG motifs found in the first and second transmembrane segments of Tim23 are necessary for the structural integrity of the TIM23 complex. ..
  30. Schendzielorz A, Schulz C, Lytovchenko O, Clancy A, Guiard B, Ieva R, et al. Two distinct membrane potential-dependent steps drive mitochondrial matrix protein translocation. J Cell Biol. 2017;216:83-92 pubmed publisher
    ..The ??- and Pam17-dependent import step identified in this study is positioned between the two known energy-dependent steps: ??-driven presequence translocation and adenosine triphosphate-driven import motor activity. ..
  31. Ting S, Schilke B, Hayashi M, Craig E. Architecture of the TIM23 inner mitochondrial translocon and interactions with the matrix import motor. J Biol Chem. 2014;289:28689-96 pubmed publisher
    ..cross-linker in the matrix exposed loop between transmembrane domains 1 and 2 (loop 1) cross-linked to Tim44. Alterations in this loop destabilized interaction of Tim44 with the translocon...
  32. 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
    ..1) the matrix-localized, ATP-hydrolyzing, 70-kDa heat shock protein mHsp70; 2) its anchor to the import channel, Tim44; 3) the nucleotide exchange factor Mge1; and 4) a J-domain-containing complex of co-chaperones, Tim14/Pam18-Tim16/..
  33. 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
    ..the inner membrane through interactions with the J-protein complex Pam16-Pam18 (Tim16-Tim14) and its cochaperone Tim44. The recently identified non-essential Pam17 is a further member of PAM...
  34. Haucke V, Schatz G. Reconstitution of the protein insertion machinery of the mitochondrial inner membrane. EMBO J. 1997;16:4560-7 pubmed
    ..The protein insertion machinery can thus operate independently of the energy-transducing Tim44p-mhsp70 complex. ..
  35. Gebert M, Schrempp S, Mehnert C, Heißwolf A, Oeljeklaus S, Ieva R, et al. Mgr2 promotes coupling of the mitochondrial presequence translocase to partner complexes. J Cell Biol. 2012;197:595-604 pubmed publisher
    ..We conclude that Mgr2 is a coupling factor of the presequence translocase crucial for cell growth at elevated temperature and for efficient protein import. ..
  36. 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. ..
  37. Sichting M, Mokranjac D, Azem A, Neupert W, Hell K. Maintenance of structure and function of mitochondrial Hsp70 chaperones requires the chaperone Hep1. EMBO J. 2005;24:1046-56 pubmed
    ..This process is efficiently counteracted by Hep1. We conclude that Hep1 acts as a chaperone that is necessary and sufficient to prevent self-aggregation and to thereby maintain the function of the mitochondrial Hsp70 chaperones. ..
  38. Banerjee R, Gladkova C, Mapa K, Witte G, Mokranjac D. Protein translocation channel of mitochondrial inner membrane and matrix-exposed import motor communicate via two-domain coupling protein. elife. 2015;4:e11897 pubmed publisher
    ..How these two processes are coordinated remained unclear. We show here that the two domain structure of Tim44 plays a central role in this process...
  39. SCHULKE N, Sepuri N, Gordon D, Saxena S, Dancis A, Pain D. A multisubunit complex of outer and inner mitochondrial membrane protein translocases stabilized in vivo by translocation intermediates. J Biol Chem. 1999;274:22847-54 pubmed
    ..Tim components known to be essential for import of matrix-targeted proteins, namely Tom40, Tom22, Tim17, Tim23, Tim44, and matrix-localized Hsp70...
  40. Schilke B, Hayashi M, Craig E. Genetic analysis of complex interactions among components of the mitochondrial import motor and translocon in Saccharomyces cerevisiae. Genetics. 2012;190:1341-53 pubmed publisher
    ..Hsp70 is tethered to the translocon via interaction with Tim44. Pam18, the J-protein co-chaperone, and Pam16, a structurally related protein with which Pam18 forms a heterodimer,..
  41. Demishtein Zohary K, Gunsel U, Marom M, Banerjee R, Neupert W, Azem A, et al. Role of Tim17 in coupling the import motor to the translocation channel of the mitochondrial presequence translocase. elife. 2017;6: pubmed publisher
  42. 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
    ..is tethered to the translocon channel at the matrix side of the inner membrane by the peripheral membrane protein Tim44. A key question in mitochondrial import is how the mtHsp70-Tim44 interaction is regulated...
  43. Ting S, Yan N, Schilke B, Craig E. Dual interaction of scaffold protein Tim44 of mitochondrial import motor with channel-forming translocase subunit Tim23. elife. 2017;6: pubmed publisher
    ..Inward movement is driven by the matrix-localized, Hsp70-based motor. The scaffold Tim44, interacting with the matrix face of the translocon, recruits other motor subunits and binds incoming presequence...
  44. Geissler A, Krimmer T, Schönfisch B, Meijer M, Rassow J. Biogenesis of the yeast frataxin homolog Yfh1p. Tim44-dependent transfer to mtHsp70 facilitates folding of newly imported proteins in mitochondria. Eur J Biochem. 2000;267:3167-80 pubmed
    b>Tim44 is an essential component of the mitochondrial inner membrane protein import machinery. In this study we asked if Tim44 is of relevance in intramitochondrial protein folding...
  45. Tamura Y, Endo T, Iijima M, Sesaki H. Ups1p and Ups2p antagonistically regulate cardiolipin metabolism in mitochondria. J Cell Biol. 2009;185:1029-45 pubmed publisher
    ..Furthermore, we observed synthetic growth defects in ups mutants in combination with loss of Pam17p, which controls the integrity of PAM. Our findings provide a novel molecular mechanism for the regulation of cardiolipin metabolism. ..
  46. 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...
  47. Matta S, Pareek G, Bankapalli K, Oblesha A, D Silva P. Role of Tim17 Transmembrane Regions in Regulating the Architecture of Presequence Translocase and Mitochondrial DNA Stability. Mol Cell Biol. 2017;37: pubmed publisher
    ..We conclude that the integrity of Tim17 transmembrane regions is critical for mitochondrial function and protein turnover. ..
  48. 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
    ..the mitochondrial matrix consists of the matrix heat shock protein Hsp70 (mtHsp70) and the translocase subunit Tim44 of the inner membrane...
  49. 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
    b>Tim44 is a protein of the mitochondrial inner membrane and serves as an adaptor protein for mtHsp70 that drives the import of preproteins in an ATP-dependent manner...
  50. 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 pubmed
    ..drives preprotein import into the mitochondrial matrix by a specific interaction with the translocase component Tim44. Two other mitochondrial Hsp70s, Ssc3 (Ecm10) and Ssq1, show high sequence homology to Ssc1 but fail to replace ..
  51. 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
    ..The components Tim17, Tim23 and Tim44 are present in this complex in equimolar amounts...
  52. Mokranjac D, Sichting M, Popov Celeketic D, Berg A, Hell K, Neupert W. The import motor of the yeast mitochondrial TIM23 preprotein translocase contains two different J proteins, Tim14 and Mdj2. J Biol Chem. 2005;280:31608-14 pubmed
    ..b>Tim44 is the central component of the motor. It recruits mtHsp70, which binds the incoming preproteins...
  53. 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. ..
  54. Josyula R, Jin Z, McCombs D, Delucas L, Sha B. Preliminary crystallographic studies of yeast mitochondrial peripheral membrane protein Tim44p. Acta Crystallogr Sect F Struct Biol Cryst Commun. 2006;62:172-4 pubmed
    ..25, c = 77.83 A. There is one Tim44p molecule in one asymmetric unit, which corresponds to a solvent content of approximately 43%. Structure determination by MAD methods is under way. ..
  55. 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
    ..favors formation of a complex on the inner membrane; this 'import complex' contains mhsp70, its membrane anchor Tim44 and the nucleotide exchange factor mGrpE...