Translocase of outer mitochondrial membrane 34 (TOMM34) orchestrates heat shock protein 70 (HSP70)/HSP90-mediated transport of mitochondrial precursor proteins. Here, using in vitro phosphorylation and refolding assays, analytical size-exclusion chromatography, and hydrogen/deuterium exchange MS, we found that TOMM34 associates with 14-3-3 proteins after its phosphorylation by protein kinase A (PKA). PKA preferentially targeted two serine residues in TOMM34: Ser93 and Ser160, located in the tetratricopeptide repeat 1 (TPR1) domain and the interdomain linker, respectively. Both of these residues were necessary for efficient 14-3-3 protein binding. We determined that phosphorylation-induced structural changes in TOMM34 are further augmented by binding to 14-3-3, leading to destabilization of TOMM34's secondary structure. We also observed that this interaction with 14-3-3 occludes the TOMM34 interaction interface with ATP-bound HSP70 dimers, which leaves them intact and thereby eliminates an inhibitory effect of TOMM34 on HSP70-mediated refolding in vitro In contrast, we noted that TOMM34 in complex with 14-3-3 could bind HSP90. Both TOMM34 and 14-3-3 participated in cytosolic precursor protein transport mediated by the coordinated activities of HSP70 and HSP90. Our results provide important insights into how PKA-mediated phosphorylation and 14-3-3 binding regulate the availability of TOMM34 for its interaction with HSP70.

• Klíčová slova
• 14-3-3 protein, 70-kDa heat shock protein (Hsp70), HSP70, Hsp70, Tomm34, dimerization, hydrogen-deuterium exchange, molecular chaperone, phosphorylation, protein folding, protein import, protein kinase A (PKA), protein-nucleic acid interaction, protein–protein interaction, translocase of outer mitochondrial membrane 34 (TOMM34),
• MeSH
• DNA vazebné proteiny genetika   metabolismus   MeSH
• fosforylace fyziologie   MeSH
• lidé MeSH
• MFC-7 buňky MeSH
• mitochondriální importní komplex MeSH
• mitochondriální membrány metabolismus   MeSH
• mitochondriální proteiny metabolismus   MeSH
• molekulární chaperony metabolismus   MeSH
• proteinkinasy závislé na cyklickém AMP metabolismus   MeSH
• proteiny 14-3-3 metabolismus   MeSH
• proteiny tepelného šoku HSP70 metabolismus   MeSH
• proteiny tepelného šoku HSP72 metabolismus   MeSH
• proteiny tepelného šoku HSP90 metabolismus   MeSH
• signální transdukce MeSH
• transkripční faktory genetika   metabolismus   MeSH
• transportní proteiny mitochondriální membrány genetika   metabolismus   MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• BCL2-associated athanogene 1 protein MeSH Prohlížeč
• DNA vazebné proteiny MeSH
• mitochondriální importní komplex MeSH
• mitochondriální proteiny MeSH
• molekulární chaperony MeSH
• proteinkinasy závislé na cyklickém AMP MeSH
• proteiny 14-3-3 MeSH
• proteiny tepelného šoku HSP70 MeSH
• proteiny tepelného šoku HSP72 MeSH
• proteiny tepelného šoku HSP90 MeSH
• TOMM34 protein, human MeSH Prohlížeč
• transkripční faktory MeSH
• transportní proteiny mitochondriální membrány MeSH

The heme-based oxygen sensor histidine kinase AfGcHK is part of a two-component signal transduction system in bacteria. O2 binding to the Fe(II) heme complex of its N-terminal globin domain strongly stimulates autophosphorylation at His183 in its C-terminal kinase domain. The 6-coordinate heme Fe(III)-OH- and -CN- complexes of AfGcHK are also active, but the 5-coordinate heme Fe(II) complex and the heme-free apo-form are inactive. Here, we determined the crystal structures of the isolated dimeric globin domains of the active Fe(III)-CN- and inactive 5-coordinate Fe(II) forms, revealing striking structural differences on the heme-proximal side of the globin domain. Using hydrogen/deuterium exchange coupled with mass spectrometry to characterize the conformations of the active and inactive forms of full-length AfGcHK in solution, we investigated the intramolecular signal transduction mechanisms. Major differences between the active and inactive forms were observed on the heme-proximal side (helix H5), at the dimerization interface (helices H6 and H7 and loop L7) of the globin domain and in the ATP-binding site (helices H9 and H11) of the kinase domain. Moreover, separation of the sensor and kinase domains, which deactivates catalysis, increased the solvent exposure of the globin domain-dimerization interface (helix H6) as well as the flexibility and solvent exposure of helix H11. Together, these results suggest that structural changes at the heme-proximal side, the globin domain-dimerization interface, and the ATP-binding site are important in the signal transduction mechanism of AfGcHK. We conclude that AfGcHK functions as an ensemble of molecules sampling at least two conformational states.

• Klíčová slova
• bacterial protein kinase, crystal structure, globin, heme-containing oxygen sensor, histidine kinase, hydrogen-deuterium exchange, signal transduction, two component signal transduction system,
• MeSH
• bakteriální proteiny chemie   metabolismus   MeSH
• fosforylace MeSH
• hem chemie   MeSH
• histidinkinasa chemie   metabolismus   MeSH
• hmotnostní spektrometrie MeSH
• krystalografie rentgenová MeSH
• kvarterní struktura proteinů MeSH
• kyslík metabolismus   MeSH
• molekulární modely MeSH
• Myxococcales metabolismus   MeSH
• oxidace-redukce MeSH
• proteinové domény MeSH
• signální transdukce MeSH
• vodík-deuteriová výměna MeSH
• železité sloučeniny chemie   MeSH
• železnaté sloučeniny chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální proteiny MeSH
• hem MeSH
• histidinkinasa MeSH
• kyslík MeSH
• železité sloučeniny MeSH
• železnaté sloučeniny MeSH

The 14-3-3 proteins, a family of highly conserved scaffolding proteins ubiquitously expressed in all eukaryotic cells, interact with and regulate the function of several hundreds of partner proteins. Yeast neutral trehalases (Nth), enzymes responsible for the hydrolysis of trehalose to glucose, compared with trehalases from other organisms, possess distinct structure and regulation involving phosphorylation at multiple sites followed by binding to the 14-3-3 protein. Here we report the crystal structures of yeast Nth1 and its complex with Bmh1 (yeast 14-3-3 isoform), which, together with mutational and fluorescence studies, indicate that the binding of Nth1 by 14-3-3 triggers Nth1's activity by enabling the proper 3D configuration of Nth1's catalytic and calcium-binding domains relative to each other, thus stabilizing the flexible part of the active site required for catalysis. The presented structure of the Bmh1:Nth1 complex highlights the ability of 14-3-3 to modulate the structure of a multidomain binding partner and to function as an allosteric effector. Furthermore, comparison of the Bmh1:Nth1 complex structure with those of 14-3-3:serotonin N-acetyltransferase and 14-3-3:heat shock protein beta-6 complexes revealed similarities in the 3D structures of bound partner proteins, suggesting the highly conserved nature of 14-3-3 affects the structures of many client proteins.

• Klíčová slova
• 14-3-3 protein, allostery, crystal structure, enzyme, trehalase,
• MeSH
• arylalkylamin-N-acetyltransferasa metabolismus   MeSH
• chemické databáze * MeSH
• fosforylace MeSH
• glukosa metabolismus   MeSH
• katalytická doména MeSH
• konformace proteinů MeSH
• krystalografie rentgenová MeSH
• molekulární modely MeSH
• proteinové domény MeSH
• proteiny 14-3-3 genetika   metabolismus   MeSH
• proteiny teplotního šoku chemie   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny chemie   metabolismus   MeSH
• Saccharomyces cerevisiae enzymologie   genetika   metabolismus   MeSH
• trehalasa chemie   metabolismus   MeSH
• trehalosa metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• arylalkylamin-N-acetyltransferasa MeSH
• glukosa MeSH
• NTH1 protein, S cerevisiae MeSH Prohlížeč
• proteiny 14-3-3 MeSH
• proteiny teplotního šoku MeSH
• Saccharomyces cerevisiae - proteiny MeSH
• trehalasa MeSH
• trehalosa MeSH

Co-chaperones containing tetratricopeptide repeat (TPR) domains enable cooperation between Hsp70 and Hsp90 to maintain cellular proteostasis. Although the details of the molecular interactions between some TPR domains and heat shock proteins are known, we describe a novel mechanism by which Tomm34 interacts with and coordinates Hsp70 activities. In contrast to the previously defined Hsp70/Hsp90-organizing protein (Hop), Tomm34 interaction is dependent on the Hsp70 chaperone cycle. Tomm34 binds Hsp70 in a complex process; anchorage of the Hsp70 C terminus by the TPR1 domain is accompanied by additional contacts formed exclusively in the ATP-bound state of Hsp70 resulting in a high affinity entropically driven interaction. Tomm34 induces structural changes in determinants within the Hsp70-lid subdomain and modulates Hsp70/Hsp40-mediated refolding and Hsp40-stimulated Hsp70 ATPase activity. Because Tomm34 recruits Hsp90 through its TPR2 domain, we propose a model in which Tomm34 enables Hsp70/Hsp90 scaffolding and influences the Hsp70 chaperone cycle, providing an additional role for co-chaperones that contain multiple TPR domains in regulating protein homeostasis.

• MeSH
• adenosintrifosfát metabolismus   MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• mitochondriální importní komplex MeSH
• molekulární modely MeSH
• mutace MeSH
• proteiny tepelného šoku HSP70 chemie   metabolismus   MeSH
• sbalování proteinů MeSH
• simulace molekulového dockingu MeSH
• terciární struktura proteinů MeSH
• transportní proteiny mitochondriální membrány chemie   genetika   metabolismus   MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• adenosintrifosfát MeSH
• mitochondriální importní komplex MeSH
• proteiny tepelného šoku HSP70 MeSH
• TOMM34 protein, human MeSH Prohlížeč
• transportní proteiny mitochondriální membrány MeSH

Phosducin (Pdc), a highly conserved phosphoprotein involved in the regulation of retinal phototransduction cascade, transcriptional control, and modulation of blood pressure, is controlled in a phosphorylation-dependent manner, including the binding to the 14-3-3 protein. However, the molecular mechanism of this regulation is largely unknown. Here, the solution structure of Pdc and its interaction with the 14-3-3 protein were investigated using small angle x-ray scattering, time-resolved fluorescence spectroscopy, and hydrogen-deuterium exchange coupled to mass spectrometry. The 14-3-3 protein dimer interacts with Pdc using surfaces both inside and outside its central channel. The N-terminal domain of Pdc, where both phosphorylation sites and the 14-3-3-binding motifs are located, is an intrinsically disordered protein that reduces its flexibility in several regions without undergoing dramatic disorder-to-order transition upon binding to 14-3-3. Our data also indicate that the C-terminal domain of Pdc interacts with the outside surface of the 14-3-3 dimer through the region involved in Gtβγ binding. In conclusion, we show that the 14-3-3 protein interacts with and sterically occludes both the N- and C-terminal Gtβγ binding interfaces of phosphorylated Pdc, thus providing a mechanistic explanation for the 14-3-3-dependent inhibition of Pdc function.

• Klíčová slova
• 14-3-3 protein, fluorescence, hydrogen-deuterium exchange, phosducin, protein complex, protein phosphorylation, small-angle x-ray scattering (SAXS),
• MeSH
• fosfoproteiny chemie   genetika   metabolismus   MeSH
• fosforylace MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• molekulární modely MeSH
• oční proteiny chemie   genetika   metabolismus   MeSH
• proteiny 14-3-3 chemie   genetika   metabolismus   MeSH
• proteiny vázající GTP - regulátory chemie   genetika   metabolismus   MeSH
• sekvence aminokyselin MeSH
• terciární struktura proteinů MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfoproteiny MeSH
• oční proteiny MeSH
• phosducin MeSH Prohlížeč
• proteiny 14-3-3 MeSH
• proteiny vázající GTP - regulátory MeSH
• YWHAZ protein, human MeSH Prohlížeč

Trehalases hydrolyze the non-reducing disaccharide trehalose amassed by cells as a universal protectant and storage carbohydrate. Recently, it has been shown that the activity of neutral trehalase Nth1 from Saccharomyces cerevisiae is mediated by the 14-3-3 protein binding that modulates the structure of both the catalytic domain and the region containing the EF-hand-like motif, whose role in the activation of Nth1 is unclear. In this work, the structure of the Nth1·14-3-3 complex and the importance of the EF-hand-like motif were investigated using site-directed mutagenesis, hydrogen/deuterium exchange coupled to mass spectrometry, chemical cross-linking, and small angle x-ray scattering. The low resolution structural views of Nth1 alone and the Nth1·14-3-3 complex show that the 14-3-3 protein binding induces a significant structural rearrangement of the whole Nth1 molecule. The EF-hand-like motif-containing region forms a separate domain that interacts with both the 14-3-3 protein and the catalytic trehalase domain. The structural integrity of the EF-hand like motif is essential for the 14-3-3 protein-mediated activation of Nth1, and calcium binding, although not required for the activation, facilitates this process by affecting its structure. Our data suggest that the EF-hand like motif-containing domain functions as the intermediary through which the 14-3-3 protein modulates the function of the catalytic domain of Nth1.

• Klíčová slova
• 14–3-3, Bmh, Calcium, Enzyme Mechanisms, H/D Exchange, Mass Spectrometry (MS), Neutral Trehalase, Protein Cross-linking, Protein Structure, SAXS,
• MeSH
• aktivace enzymů MeSH
• katalytická doména MeSH
• molekulární modely MeSH
• motivy EF-ruky * MeSH
• proteiny 14-3-3 chemie   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny chemie   metabolismus   MeSH
• Saccharomyces cerevisiae enzymologie   MeSH
• sekvence aminokyselin MeSH
• trehalasa chemie   metabolismus   MeSH
• vápník metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• BMH1 protein, S cerevisiae MeSH Prohlížeč
• proteiny 14-3-3 MeSH
• Saccharomyces cerevisiae - proteiny MeSH
• trehalasa MeSH
• vápník MeSH

Maintenance of protein homeostasis by molecular chaperones Hsp70 and Hsp90 requires their spatial and functional coordination. The cooperation of Hsp70 and Hsp90 is influenced by their interaction with the network of co-chaperone proteins, some of which contain tetratricopeptide repeat (TPR) domains. Critical to these interactions are TPR domains that target co-chaperone binding to the EEVD-COOH motif that terminates Hsp70/Hsp90. Recently, the two-TPR domain-containing protein, Tomm34, was reported to bind both Hsp70 and Hsp90. Here we characterize the structural basis of Tomm34-Hsp70/Hsp90 interactions. Using multiple methods, including pull-down assays, fluorescence polarization, hydrogen/deuterium exchange, and site-directed mutagenesis, we defined the binding activities and specificities of Tomm34 TPR domains toward Hsp70 and Hsp90. We found that Tomm34 TPR1 domain specifically binds Hsp70. This interaction is partly mediated by a non-canonical TPR1 two-carboxylate clamp and is strengthened by so far unidentified additional intermolecular contacts. The two-carboxylate clamp of the isolated TPR2 domain has affinity for both chaperones, but as part of the full-length Tomm34 protein, the TPR2 domain binds specifically Hsp90. These binding properties of Tomm34 TPR domains thus enable simultaneous binding of Hsp70 and Hsp90. Importantly, we provide evidence for the existence of an Hsp70-Tomm34-Hsp90 tripartite complex. In addition, we defined the basic conformational demands of the Tomm34-Hsp90 interaction. These results suggest that Tomm34 represents a novel scaffolding co-chaperone of Hsp70 and Hsp90, which may facilitate Hsp70/Hsp90 cooperation during protein folding.

• Klíčová slova
• Co-chaperone, H/D Exchange, Hsp70, Hsp90, Molecular Chaperone, Protein Assembly, Protein Folding, Protein-Protein Interactions, TPR Domain,
• MeSH
• aminokyselinové motivy MeSH
• HEK293 buňky MeSH
• kvarterní struktura proteinů MeSH
• lidé MeSH
• missense mutace MeSH
• mitochondriální importní komplex MeSH
• multiproteinové komplexy * chemie   genetika   metabolismus   MeSH
• mutageneze cílená MeSH
• proteiny tepelného šoku HSP70 * chemie   genetika   metabolismus   MeSH
• proteiny tepelného šoku HSP90 * chemie   genetika   metabolismus   MeSH
• sbalování proteinů * MeSH
• substituce aminokyselin MeSH
• terciární struktura proteinů MeSH
• transportní proteiny mitochondriální membrány * chemie   genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• HSP90AA1 protein, human MeSH Prohlížeč
• HSPA1A protein, human MeSH Prohlížeč
• mitochondriální importní komplex MeSH
• multiproteinové komplexy * MeSH
• proteiny tepelného šoku HSP70 * MeSH
• proteiny tepelného šoku HSP90 * MeSH
• TOMM34 protein, human MeSH Prohlížeč
• transportní proteiny mitochondriální membrány * MeSH

Phosducin (Pdc), a highly conserved phosphoprotein, plays an important role in the regulation of G protein signaling, transcriptional control, and modulation of blood pressure. Pdc is negatively regulated by phosphorylation followed by binding to the 14-3-3 protein, whose role is still unclear. To gain insight into the role of 14-3-3 in the regulation of Pdc function, we studied structural changes of Pdc induced by phosphorylation and 14-3-3 protein binding using time-resolved fluorescence spectroscopy. Our data show that the phosphorylation of the N-terminal domain of Pdc at Ser-54 and Ser-73 affects the structure of the whole Pdc molecule. Complex formation with 14-3-3 reduces the flexibility of both the N- and C-terminal domains of phosphorylated Pdc, as determined by time-resolved tryptophan and dansyl fluorescence. Therefore, our data suggest that phosphorylated Pdc undergoes a conformational change when binding to 14-3-3. These changes involve the G(t)βγ binding surface within the N-terminal domain of Pdc, and thus could explain the inhibitory effect of 14-3-3 on Pdc function.

• MeSH
• fluorescenční spektrometrie MeSH
• fosfatidylcholiny MeSH
• fosfoproteiny chemie   metabolismus   MeSH
• fosforylace MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• oční proteiny chemie   metabolismus   MeSH
• proteiny 14-3-3 metabolismus   MeSH
• proteiny vázající GTP - regulátory chemie   metabolismus   MeSH
• sekvence aminokyselin MeSH
• serin metabolismus   MeSH
• terciární struktura proteinů MeSH
• tryptofan MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1-myristoyl-2-(12-((5-dimethylamino-1-naphthalenesulfonyl)amino)dodecanoyl)-sn-glycero-3-phosphocholine MeSH Prohlížeč
• fosfatidylcholiny MeSH
• fosfoproteiny MeSH
• oční proteiny MeSH
• phosducin MeSH Prohlížeč
• proteiny 14-3-3 MeSH
• proteiny vázající GTP - regulátory MeSH
• serin MeSH
• tryptofan MeSH
• YWHAZ protein, human MeSH Prohlížeč