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Zuccaro KE, Abriata LA, Meireles FTP, Moss FR, Frost A, Dal Peraro M, Aydin H. Cardiolipin clustering promotes mitochondrial membrane dynamics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.21.595226. [PMID: 38826344 PMCID: PMC11142133 DOI: 10.1101/2024.05.21.595226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Cardiolipin (CL) is a mitochondria-specific phospholipid that forms heterotypic interactions with membrane-shaping proteins and regulates the dynamic remodeling and function of mitochondria. However, the precise mechanisms through which CL influences mitochondrial morphology are not well understood. In this study, employing molecular dynamics (MD) simulations, we observed CL localize near the membrane-binding sites of the mitochondrial fusion protein Optic Atrophy 1 (OPA1). To validate these findings experimentally, we developed a bromine-labeled CL probe to enhance cryoEM contrast and characterize the structure of OPA1 assemblies bound to the CL-brominated lipid bilayers. Our images provide direct evidence of interactions between CL and two conserved motifs within the paddle domain (PD) of OPA1, which control membrane-shaping mechanisms. We further observed a decrease in membrane remodeling activity for OPA1 in lipid compositions with increasing concentrations of monolyso-cardiolipin (MLCL). Suggesting that the partial replacement of CL by MLCL accumulation, as observed in Barth syndrome-associated mutations of the tafazzin phospholipid transacylase, compromises the stability of protein-membrane interactions. Our analyses provide insights into how biological membranes regulate the mechanisms governing mitochondrial homeostasis. Teaser This study reveals how CL modulates the activity of OPA1 and how MLCL impacts its ability to govern mitochondrial function.
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Feng S, Aplin C, Nguyen TTT, Milano SK, Cerione RA. Filament formation drives catalysis by glutaminase enzymes important in cancer progression. Nat Commun 2024; 15:1971. [PMID: 38438397 PMCID: PMC10912226 DOI: 10.1038/s41467-024-46351-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 02/22/2024] [Indexed: 03/06/2024] Open
Abstract
The glutaminase enzymes GAC and GLS2 catalyze the hydrolysis of glutamine to glutamate, satisfying the 'glutamine addiction' of cancer cells. They are the targets of anti-cancer drugs; however, their mechanisms of activation and catalytic activity have been unclear. Here we demonstrate that the ability of GAC and GLS2 to form filaments is directly coupled to their catalytic activity and present their cryo-EM structures which provide a view of the conformational states essential for catalysis. Filament formation guides an 'activation loop' to assume a specific conformation that works together with a 'lid' to close over the active site and position glutamine for nucleophilic attack by an essential serine. Our findings highlight how ankyrin repeats on GLS2 regulate enzymatic activity, while allosteric activators stabilize, and clinically relevant inhibitors block, filament formation that enables glutaminases to catalyze glutaminolysis and support cancer progression.
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Affiliation(s)
- Shi Feng
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Cody Aplin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Thuy-Tien T Nguyen
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Shawn K Milano
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Richard A Cerione
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA.
- Department of Molecular Medicine, Cornell University, Ithaca, NY, 14853, USA.
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Ma Z, Sun J, Jiang Q, Zhao Y, Jiang H, Sun P, Feng W. Identification and analysis of mitochondria-related central genes in steroid-induced osteonecrosis of the femoral head, along with drug prediction. Front Endocrinol (Lausanne) 2024; 15:1341366. [PMID: 38384969 PMCID: PMC10879930 DOI: 10.3389/fendo.2024.1341366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 01/19/2024] [Indexed: 02/23/2024] Open
Abstract
Purpose Steroid-induced osteonecrosis of the femoral head (SONFH) is a refractory orthopedic hip joint disease that primarily affects middle-aged and young individuals. SONFH may be caused by ischemia and hypoxia of the femoral head, where mitochondria play a crucial role in oxidative reactions. Currently, there is limited literature on whether mitochondria are involved in the progression of SONFH. Here, we aim to identify and validate key potential mitochondrial-related genes in SONFH through bioinformatics analysis. This study aims to provide initial evidence that mitochondria play a role in the progression of SONFH and further elucidate the mechanisms of mitochondria in SONFH. Methods The GSE123568 mRNA expression profile dataset includes 10 non-SONFH (non-steroid-induced osteonecrosis of the femoral head) samples and 30 SONFH samples. The GSE74089 mRNA expression profile dataset includes 4 healthy samples and 4 samples with ischemic necrosis of the femoral head. Both datasets were downloaded from the Gene Expression Omnibus (GEO) database. The mitochondrial-related genes are derived from MitoCarta3.0, which includes data for all 1136 human genes with high confidence in mitochondrial localization based on integrated proteomics, computational, and microscopy approaches. By intersecting the GSE123568 and GSE74089 datasets with a set of mitochondrial-related genes, we screened for mitochondrial-related genes involved in SONFH. Subsequently, we used the good Samples Genes method in R language to remove outlier genes and samples in the GSE123568 dataset. We further used WGCNA to construct a scale-free co-expression network and selected the hub gene set with the highest connectivity. We then intersected this gene set with the previously identified mitochondrial-related genes to select the genes with the highest correlation. A total of 7 mitochondrial-related genes were selected. Next, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis on the selected mitochondrial-related genes using R software. Furthermore, we performed protein network analysis on the differentially expressed proteins encoded by the mitochondrial genes using STRING. We used the GSEA software to group the genes within the gene set in the GSE123568 dataset based on their coordinated changes and evaluate their impact on phenotype changes. Subsequently, we grouped the samples based on the 7 selected mitochondrial-related genes using R software and observed the differences in immune cell infiltration between the groups. Finally, we evaluated the prognostic significance of these features in the two datasets, consisting of a total of 48 samples, by integrating disease status and the 7 gene features using the cox method in the survival R package. We performed ROC analysis using the roc function in the pROC package and evaluated the AUC and confidence intervals using the ci function to obtain the final AUC results. Results Identification and analysis of 7 intersecting DEGs (differentially expressed genes) were obtained among peripheral blood, cartilage samples, hub genes, and mitochondrial-related genes. These 7 DEGs include FTH1, LACTB, PDK3, RAB5IF, SOD2, and SQOR, all of which are upregulated genes with no intersection in the downregulated gene set. Subsequently, GO and KEGG pathway enrichment analysis revealed that the upregulated DEGs are primarily involved in processes such as oxidative stress, release of cytochrome C from mitochondria, negative regulation of intrinsic apoptotic signaling pathway, cell apoptosis, mitochondrial metabolism, p53 signaling pathway, and NK cell-mediated cytotoxicity. GSEA also revealed enriched pathways associated with hub genes. Finally, the diagnostic value of these key genes for hormone-related ischemic necrosis of the femoral head (SONFH) was confirmed using ROC curves. Conclusion BID, FTH1, LACTB, PDK3, RAB5IF, SOD2, and SQOR may serve as potential diagnostic mitochondrial-related biomarkers for SONFH. Additionally, they hold research value in investigating the involvement of mitochondria in the pathogenesis of ischemic necrosis of the femoral head.
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Affiliation(s)
- Zheru Ma
- Department of Bone and Joint Surgery, Orthopaedic Center, The First Hospital of Jilin University, Chang chun, China
| | - Jing Sun
- Department of Otolaryngology Head and Neck Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Qi Jiang
- Department of Respiratory Medicine, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Yao Zhao
- Department of Bone and Joint Surgery, Orthopaedic Center, The First Hospital of Jilin University, Chang chun, China
| | - Haozhuo Jiang
- Department of Bone and Joint Surgery, Orthopaedic Center, The First Hospital of Jilin University, Chang chun, China
| | - Peng Sun
- Department of Bone and Joint Surgery, Orthopaedic Center, The First Hospital of Jilin University, Chang chun, China
| | - Wei Feng
- Department of Bone and Joint Surgery, Orthopaedic Center, The First Hospital of Jilin University, Chang chun, China
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Ghadirian N, Morgan RD, Horton NC. DNA Sequence Control of Enzyme Filamentation and Activation of the SgrAI Endonuclease. Biochemistry 2024; 63:326-338. [PMID: 38207281 DOI: 10.1021/acs.biochem.3c00313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Enzyme polymerization (also known as filamentation) has emerged as a new layer of enzyme regulation. SgrAI is a sequence-dependent DNA endonuclease that forms polymeric filaments with enhanced DNA cleavage activity as well as altered DNA sequence specificity. To better understand this unusual regulatory mechanism, full global kinetic modeling of the reaction pathway, including the enzyme filamentation steps, has been undertaken. Prior work with the primary DNA recognition sequence cleaved by SgrAI has shown how the kinetic rate constants of each reaction step are tuned to maximize activation and DNA cleavage while minimizing the extent of DNA cleavage to the host genome. In the current work, we expand on our prior study by now including DNA cleavage of a secondary recognition sequence, to understand how the sequence of the bound DNA modulates filamentation and activation of SgrAI. The work shows that an allosteric equilibrium between low and high activity states is modulated by the sequence of bound DNA, with primary sequences more prone to activation and filament formation, while SgrAI bound to secondary recognition sequences favor the low (and nonfilamenting) state by up to 40-fold. In addition, the degree of methylation of secondary sequences in the host organism, Streptomyces griseus, is now reported for the first time and shows that as predicted, these sequences are left unprotected from the SgrAI endonuclease making sequence specificity critical in this unusual filament-forming enzyme.
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Affiliation(s)
- Niloofar Ghadirian
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Richard D Morgan
- New England Biolabs, Inc., Ipswich, Massachusetts 01938, United States
| | - Nancy C Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, United States
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von der Malsburg A, Sapp GM, Zuccaro KE, von Appen A, Moss FR, Kalia R, Bennett JA, Abriata LA, Dal Peraro M, van der Laan M, Frost A, Aydin H. Structural mechanism of mitochondrial membrane remodelling by human OPA1. Nature 2023; 620:1101-1108. [PMID: 37612504 PMCID: PMC10875962 DOI: 10.1038/s41586-023-06441-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 07/14/2023] [Indexed: 08/25/2023]
Abstract
Distinct morphologies of the mitochondrial network support divergent metabolic and regulatory processes that determine cell function and fate1-3. The mechanochemical GTPase optic atrophy 1 (OPA1) influences the architecture of cristae and catalyses the fusion of the mitochondrial inner membrane4,5. Despite its fundamental importance, the molecular mechanisms by which OPA1 modulates mitochondrial morphology are unclear. Here, using a combination of cellular and structural analyses, we illuminate the molecular mechanisms that are key to OPA1-dependent membrane remodelling and fusion. Human OPA1 embeds itself into cardiolipin-containing membranes through a lipid-binding paddle domain. A conserved loop within the paddle domain inserts deeply into the bilayer, further stabilizing the interactions with cardiolipin-enriched membranes. OPA1 dimerization through the paddle domain promotes the helical assembly of a flexible OPA1 lattice on the membrane, which drives mitochondrial fusion in cells. Moreover, the membrane-bending OPA1 oligomer undergoes conformational changes that pull the membrane-inserting loop out of the outer leaflet and contribute to the mechanics of membrane remodelling. Our findings provide a structural framework for understanding how human OPA1 shapes mitochondrial morphology and show us how human disease mutations compromise OPA1 functions.
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Affiliation(s)
- Alexander von der Malsburg
- Medical Biochemistry & Molecular Biology, Center for Molecular Signaling, PZMS, Saarland University Medical School, Homburg, Germany
| | - Gracie M Sapp
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Kelly E Zuccaro
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Alexander von Appen
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Frank R Moss
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
- Altos Labs, Bay Area Institute of Science, San Francisco, CA, USA
| | - Raghav Kalia
- Department of Physiology, University of California, San Francisco, San Francisco, CA, USA
| | - Jeremy A Bennett
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Luciano A Abriata
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Protein Production and Structure Core Facility, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Martin van der Laan
- Medical Biochemistry & Molecular Biology, Center for Molecular Signaling, PZMS, Saarland University Medical School, Homburg, Germany
| | - Adam Frost
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
- Altos Labs, Bay Area Institute of Science, San Francisco, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
- Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA, USA.
| | - Halil Aydin
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.
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