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Valdebenito S, Eugenin E, Oberhauser A. SPR spectroscopic analysis of myosin binding to wild type and mutant UNC45B. MICROPUBLICATION BIOLOGY 2024; 2024:10.17912/micropub.biology.001131. [PMID: 38404916 PMCID: PMC10884834 DOI: 10.17912/micropub.biology.001131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 01/30/2024] [Accepted: 02/02/2024] [Indexed: 02/27/2024]
Abstract
UNC45B is a multidomain molecular chaperone that is essential for the proper folding and function of myosin. It has previously been demonstrated that the UCS domain is responsible for the chaperoning function of UNC45B and that removing its client-binding loop leads to a significant change in its solution conformation and a reduced chaperoning function. Here, we report the direct quantification of affinities of myosin binding to wild type and mutant UNC45B using surface plasmon resonance (SPR) spectroscopy. We found that deletion of the client-binding loop in UNC45B resulted in a dramatic decrease in myosin affinity.
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Affiliation(s)
- Silvana Valdebenito
- The University of Texas Medical Branch at Galveston, Galveston, Texas, United States
| | - Eliseo Eugenin
- The University of Texas Medical Branch at Galveston, Galveston, Texas, United States
| | - Andres Oberhauser
- The University of Texas Medical Branch at Galveston, Galveston, Texas, United States
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2
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Kutzner CE, Bauer KC, Hoppe T. A ubiquitin fusion reporter to monitor muscle proteostasis in C. elegans. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000824. [PMID: 37159574 PMCID: PMC10163378 DOI: 10.17912/micropub.biology.000824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/11/2023] [Accepted: 04/20/2023] [Indexed: 05/11/2023]
Abstract
Muscle is a highly dynamic tissue in which a variety of folding and degradation processes are active to maintain protein homeostasis (proteostasis) and functionality. The muscle-specific chaperone UNC-45 folds the motor protein myosin and assembles it into myofilaments. Malfunction of this chaperone leads to misfolding of myosin, disorganization of myofilaments, and degradation of misfolded myosin molecules by the proteasome. Here, we present a new muscle-specific ubiquitin fusion degradation (UFD) model substrate in C. elegans that helps clarify how UNC-45 dysfunction affects muscle proteostasis.
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Affiliation(s)
- Carl Elias Kutzner
- Institute for Genetics, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), Cologne, Germany
- Center for Molecular Medicine (CMMC), Cologne, Germany
| | - Karen Carolyn Bauer
- Institute for Genetics, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), Cologne, Germany
| | - Thorsten Hoppe
- Institute for Genetics, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), Cologne, Germany
- Center for Molecular Medicine (CMMC), Cologne, Germany
- Correspondence to: Thorsten Hoppe (
)
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3
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Odunuga OO, Oberhauser AF. Beyond Chaperoning: UCS Proteins Emerge as Regulators of Myosin-Mediated Cellular Processes. Subcell Biochem 2023; 101:189-211. [PMID: 36520308 DOI: 10.1007/978-3-031-14740-1_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The UCS (UNC-45/CRO1/She4p) family of proteins has emerged as chaperones specific for the folding, assembly, and function of myosin. UCS proteins participate in various myosin-dependent cellular processes including myofibril organization and muscle functions, cell differentiation, striated muscle development, cytokinesis, and endocytosis. Mutations in the genes that code for UCS proteins cause serious defects in myosin-dependent cellular processes. UCS proteins that contain an N-terminal tetratricopeptide repeat (TPR) domain are called UNC-45. Vertebrates usually possess two variants of UNC-45, the ubiquitous general-cell UNC-45 (UNC-45A) and the striated muscle UNC-45 (UNC-45B), which is exclusively expressed in skeletal and cardiac muscles. Except for the TPR domain in UNC-45, UCS proteins comprise of several irregular armadillo (ARM) repeats that are organized into a central domain, a neck region, and the canonical C-terminal UCS domain that functions as the chaperoning module. With or without TPR, UCS proteins form linear oligomers that serve as scaffolds that mediate myosin folding, organization into myofibrils, repair, and motility. This chapter reviews emerging functions of these proteins with a focus on UNC-45 as a dedicated chaperone for folding, assembly, and function of myosin at protein and potentially gene levels. Recent experimental evidences strongly support UNC-45 as an absolute regulator of myosin, with each domain of the chaperone playing different but complementary roles during the folding, assembly, and function of myosin, as well as recruiting Hsp90 as a co-chaperone to optimize key steps. It is becoming increasingly clear that UNC-45 also regulates the transcription of several genes involved in myosin-dependent cellular processes.
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Affiliation(s)
- Odutayo O Odunuga
- Department of Chemistry and Biochemistry, Stephen F. Austin State University, Nacogdoches, TX, USA.
| | - Andres F Oberhauser
- Department of Neuroscience, Cell Biology, & Anatomy, The University of Texas Medical Branch, Galveston, TX, USA.
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4
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Piper PW, Scott JE, Millson SH. UCS Chaperone Folding of the Myosin Head: A Function That Evolved before Animals and Fungi Diverged from a Common Ancestor More than a Billion Years Ago. Biomolecules 2022; 12:biom12081028. [PMID: 35892339 PMCID: PMC9331494 DOI: 10.3390/biom12081028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 12/04/2022] Open
Abstract
The folding of the myosin head often requires a UCS (Unc45, Cro1, She4) domain-containing chaperone. Worms, flies, and fungi have just a single UCS protein. Vertebrates have two; one (Unc45A) which functions primarily in non-muscle cells and another (Unc45B) that is essential for establishing and maintaining the contractile apparatus of cardiac and skeletal muscles. The domain structure of these proteins suggests that the UCS function evolved before animals and fungi diverged from a common ancestor more than a billion years ago. UCS proteins of metazoans and apicomplexan parasites possess a tetratricopeptide repeat (TPR), a domain for direct binding of the Hsp70/Hsp90 chaperones. This, however, is absent in the UCS proteins of fungi and largely nonessential for the UCS protein function in Caenorhabditis elegans and zebrafish. The latter part of this review focusses on the TPR-deficient UCS proteins of fungi. While these are reasonably well studied in yeasts, there is little precise information as to how they might engage in interactions with the Hsp70/Hsp90 chaperones or might assist in myosin operations during the hyphal growth of filamentous fungi.
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Affiliation(s)
- Peter William Piper
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
- Correspondence: (P.W.P.); (S.H.M.)
| | | | - Stefan Heber Millson
- School of Life Sciences, University of Lincoln, Lincoln LN6 7DL, UK;
- Correspondence: (P.W.P.); (S.H.M.)
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5
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Neonatal myofibrillar myopathy type II associated with biallelic UNC-45B gene novel mutation and perinatal myasthenia as the core phenotype: a case report. Clin Chim Acta 2022; 531:12-16. [DOI: 10.1016/j.cca.2022.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/03/2022] [Indexed: 11/22/2022]
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6
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Moncrief T, Matheny CJ, Gaziova I, Miller JM, Qadota H, Benian GM, Oberhauser AF. Mutations in conserved residues of the myosin chaperone UNC-45 result in both reduced stability and chaperoning activity. Protein Sci 2021; 30:2221-2232. [PMID: 34515376 DOI: 10.1002/pro.4180] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 08/17/2021] [Accepted: 09/02/2021] [Indexed: 01/22/2023]
Abstract
Proper muscle development and function depend on myosin being properly folded and integrated into the thick filament structure. For this to occur the myosin chaperone UNC-45, or UNC-45B, must be present and able to chaperone myosin. Here we use a combination of in vivo C. elegans experiments and in vitro biophysical experiments to analyze the effects of six missense mutations in conserved regions of UNC-45/UNC-45B. We found that the phenotype of paralysis and disorganized thick filaments in 5/6 of the mutant nematode strains can likely be attributed to both reduced steady state UNC-45 protein levels and reduced chaperone activity. Interestingly, the biophysical assays performed on purified proteins show that all of the mutations result in reduced myosin chaperone activity but not overall protein stability. This suggests that these mutations only cause protein instability in the in vivo setting and that these conserved regions may be involved in UNC-45 protein stability/regulation via posttranslational modifications, protein-protein interactions, or some other unknown mechanism.
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Affiliation(s)
- Taylor Moncrief
- Department of Neuroscience, Cell Biology and Anatomy, Emory University, Atlanta, Georgia
| | | | - Ivana Gaziova
- Department of Neuroscience, Cell Biology and Anatomy, Emory University, Atlanta, Georgia
| | - John M Miller
- Department of Biochemistry and Molecular Biology, Emory University, Atlanta, Georgia
| | - Hiroshi Qadota
- Department of Pathology, Emory University, Atlanta, Georgia
| | - Guy M Benian
- Department of Pathology, Emory University, Atlanta, Georgia
| | - Andres F Oberhauser
- Department of Neuroscience, Cell Biology and Anatomy, Emory University, Atlanta, Georgia.,Department of Biochemistry and Molecular Biology, Emory University, Atlanta, Georgia.,Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas
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7
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Mutational Analysis of the Structure and Function of the Chaperoning Domain of UNC-45B. Biophys J 2020; 119:780-791. [PMID: 32755562 DOI: 10.1016/j.bpj.2020.07.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 07/09/2020] [Accepted: 07/13/2020] [Indexed: 12/29/2022] Open
Abstract
UNC-45B is a multidomain molecular chaperone that is essential for the proper folding and assembly of myosin into muscle thick filaments in vivo. It has previously been demonstrated that the UCS domain is responsible for the chaperone-like properties of the UNC-45B. To better understand the chaperoning function of the UCS domain of the UNC-45B chaperone, we engineered mutations designed to 1) disrupt chaperone-client interactions by removing and altering the structure of a putative client-interacting loop and 2) disrupt chaperone-client interactions by changing highly conserved residues in a putative client-binding groove. We tested the effect of these mutations by using a, to our knowledge, novel combination of complementary biophysical assays (circular dichroism, chaperone activity, and small-angle x-ray scattering) and in vivo tools (Caenorhabditis elegans sarcomere structure). Removing the putative client-binding loop altered the secondary structure of the UCS domain (by decreasing the α-helix content), leading to a significant change in its solution conformation and a reduced chaperoning function. Additionally, we found that mutating several conserved residues in the putative client-binding groove did not alter the UCS domain secondary structure or structural stability but reduced its chaperoning activity. In vivo, these groove mutations were found to significantly alter the structure and organization of C. elegans sarcomeres. Furthermore, we tested the effect of R805W, a mutation distant from the putative client-binding region, which in humans, has been known to cause congenital and infantile cataracts. Our in vivo data show that, to our surprise, the R805W mutation appeared to have the most drastic detrimental effect on the structure and organization of the worm sarcomeres, indicating a crucial role of R805 in UCS-client interactions. Hence, our experimental approach combining biophysical and biological tools facilitates the study of myosin-chaperone interactions in mechanistic detail.
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Srivastava D, Artemyev NO. Ric-8A, a GEF, and a Chaperone for G Protein α-Subunits: Evidence for the Two-Faced Interface. Bioessays 2020; 42:e1900208. [PMID: 31967346 PMCID: PMC7034654 DOI: 10.1002/bies.201900208] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/30/2019] [Indexed: 12/21/2022]
Abstract
Resistance to inhibitors of cholinesterase 8A (Ric-8A) is a prominent non-receptor GEF and a chaperone of G protein α-subunits (Gα). Recent studies shed light on the structure of Ric-8A, providing insights into the mechanisms underlying its interaction with Gα. Ric-8A is composed of a core armadillo-like domain and a flexible C-terminal tail. Interaction of a conserved concave surface of its core domain with the Gα C-terminus appears to mediate formation of the initial Ric-8A/GαGDP intermediate, followed by the formation of a stable nucleotide-free complex. The latter event involves a large-scale dislocation of the Gα α5-helix that produces an extensive primary interface and disrupts the nucleotide-binding site of Gα. The distal portion of the C-terminal tail of Ric-8A forms a smaller secondary interface, which ostensibly binds the switch II region of Gα, facilitating binding of GTP. The two-site Gα interface of Ric-8A is distinct from that of GPCRs, and might have evolved to support the chaperone function of Ric-8A.
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Affiliation(s)
- Dhiraj Srivastava
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA 52242
| | - Nikolai O. Artemyev
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA 52242
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242
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Srivastava D, Artemyev NO. Large-scale conformational rearrangement of the α5-helix of Gα subunits in complex with the guanine nucleotide exchange factor Ric8A. J Biol Chem 2019; 294:17875-17882. [PMID: 31624147 DOI: 10.1074/jbc.ac119.011135] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/02/2019] [Indexed: 11/06/2022] Open
Abstract
Resistance to inhibitors of cholinesterase 8A (Ric8A) protein is an important G protein-coupled receptor (GPCR)-independent regulator of G protein α-subunits (Gα), acting as a guanine nucleotide exchange factor (GEF) and a chaperone. Insights into the complex between Ric8A and Gα hold the key to understanding the mechanisms underlying noncanonical activation of G-protein signaling as well as the folding of nascent Gα proteins. Here, we examined the structure of the complex of Ric8A with minimized Gαi (miniGαi) in solution by small-angle X-ray scattering (SAXS) and exploited the scattering profile in modeling of the Ric8A/miniGαi complex by steered molecular dynamics (SMD) simulations. A small set of models of the complex featured minimal clash scores, excellent agreement with the experimental SAXS data, and a large-scale rearrangement of the signal-transducing α5-helix of Gα away from its β-sheet core. The resulting interface involved the Gα α5-helix bound to the concave surface of Ric8A and the Gα β-sheet that wraps around the C-terminal part of the Ric8A armadillo domain, leading to a severe disruption of the GDP-binding site. Further modeling of the flexible C-terminal tail of Ric8A indicated that it interacts with the effector surface of Gα. This smaller interface may enable the Ric8A-bound Gα to interact with GTP. The two-interface interaction with Gα described here distinguishes Ric8A from GPCRs and non-GPCR regulators of G-protein signaling.
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Affiliation(s)
- Dhiraj Srivastava
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Nikolai O Artemyev
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242 .,Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
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10
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Bujalowski PJ, Nicholls P, Garza E, Oberhauser AF. The central domain of UNC-45 chaperone inhibits the myosin power stroke. FEBS Open Bio 2018; 8:41-48. [PMID: 29321955 PMCID: PMC5757175 DOI: 10.1002/2211-5463.12346] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 10/27/2017] [Accepted: 10/31/2017] [Indexed: 11/07/2022] Open
Abstract
The multidomain UNC-45B chaperone is crucial for the proper folding and function of sarcomeric myosin. We recently found that UNC-45B inhibits the translocation of actin by myosin. The main functions of the UCS and TPR domains are known but the role of the central domain remains obscure. Here, we show-using in vitro myosin motility and ATPase assays-that the central domain alone acts as an inhibitor of the myosin power stroke through a mechanism that allows ATP turnover. Hence, UNC-45B is a unique chaperone in which the TPR domain recruits Hsp90; the UCS domain possesses chaperone-like activities; and the central domain interacts with myosin and inhibits the actin translocation function of myosin. We hypothesize that the inhibitory function plays a critical role during the assembly of myofibrils under stress and during the sarcomere development process.
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Affiliation(s)
- Paul J Bujalowski
- Department of Biochemistry and Molecular Biology The University of Texas Medical Branch Galveston TX USA
| | - Paul Nicholls
- Baylor College of Medicine The University of Texas Medical Branch Galveston TX USA
| | - Eleno Garza
- Department of Neuroscience and Cell Biology The University of Texas Medical Branch Galveston TX USA
| | - Andres F Oberhauser
- Department of Biochemistry and Molecular Biology The University of Texas Medical Branch Galveston TX USA.,Department of Neuroscience and Cell Biology The University of Texas Medical Branch Galveston TX USA.,Sealy Center for Structural Biology and Molecular Biophysics The University of Texas Medical Branch Galveston TX USA
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11
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Armc5 deletion causes developmental defects and compromises T-cell immune responses. Nat Commun 2017; 8:13834. [PMID: 28169274 PMCID: PMC5309699 DOI: 10.1038/ncomms13834] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 11/04/2016] [Indexed: 01/10/2023] Open
Abstract
Armadillo repeat containing 5 (ARMC5) is a cytosolic protein with no enzymatic activities. Little is known about its function and mechanisms of action, except that gene mutations are associated with risks of primary macronodular adrenal gland hyperplasia. Here we map Armc5 expression by in situ hybridization, and generate Armc5 knockout mice, which are small in body size. Armc5 knockout mice have compromised T-cell proliferation and differentiation into Th1 and Th17 cells, increased T-cell apoptosis, reduced severity of experimental autoimmune encephalitis, and defective immune responses to lymphocytic choriomeningitis virus infection. These mice also develop adrenal gland hyperplasia in old age. Yeast 2-hybrid assays identify 16 ARMC5-binding partners. Together these data indicate that ARMC5 is crucial in fetal development, T-cell function and adrenal gland growth homeostasis, and that the functions of ARMC5 probably depend on interaction with multiple signalling pathways. Mutations in ARMC5 are associated with risk of primary macronodular adrenal gland hyperplasia. Here the authors show that mice lacking Armc5 have adrenal gland hyperplasia and defective T-cell proliferation, differentiation, survival and in vivo T-cell-mediated immune responses.
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