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Fagnani E, Cocomazzi P, Pellegrino S, Tedeschi G, Scalvini FG, Cossu F, Da Vela S, Aliverti A, Mastrangelo E, Milani M. CHCHD4 binding affects the active site of apoptosis inducing factor (AIF): Structural determinants for allosteric regulation. Structure 2024; 32:594-602.e4. [PMID: 38460521 DOI: 10.1016/j.str.2024.02.008] [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] [Received: 10/03/2023] [Revised: 01/08/2024] [Accepted: 02/13/2024] [Indexed: 03/11/2024]
Abstract
Apoptosis-inducing factor (AIF), which is confined to mitochondria of normal healthy cells, is the first identified caspase-independent cell death effector. Moreover, AIF is required for the optimal functioning of the respiratory chain machinery. Recent findings have revealed that AIF fulfills its pro-survival function by interacting with CHCHD4, a soluble mitochondrial protein which promotes the entrance and the oxidative folding of different proteins in the inner membrane space. Here, we report the crystal structure of the ternary complex involving the N-terminal 27-mer peptide of CHCHD4, NAD+, and AIF harboring its FAD (flavin adenine dinucleotide) prosthetic group in oxidized form. Combining this information with biophysical and biochemical data on the CHCHD4/AIF complex, we provide a detailed structural description of the interaction between the two proteins, validated by both chemical cross-linking mass spectrometry analysis and site-directed mutagenesis.
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Affiliation(s)
- Elisa Fagnani
- Biophysics Institute, CNR-IBF, Via Corti 12, 20133 Milan, Italy; Department of Bioscience, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
| | - Paolo Cocomazzi
- Biophysics Institute, CNR-IBF, Via Corti 12, 20133 Milan, Italy; Department of Bioscience, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
| | - Sara Pellegrino
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Via Golgi 19, 20133 Milan, Italy
| | - Gabriella Tedeschi
- Department of Veterinary Medicine and Animal Science (DIVAS), Università degli Studi di Milano, Via dell'Università 6, 26900 Lodi, Italy; Cimaina, Università degli Studi di Milano, Milan, Italy
| | - Francesca Grassi Scalvini
- Department of Veterinary Medicine and Animal Science (DIVAS), Università degli Studi di Milano, Via dell'Università 6, 26900 Lodi, Italy
| | - Federica Cossu
- Biophysics Institute, CNR-IBF, Via Corti 12, 20133 Milan, Italy; Department of Bioscience, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
| | - Stefano Da Vela
- Hochschule Bremerhaven, Karlstadt 8, 27568 Bremerhaven, Germany
| | - Alessandro Aliverti
- Department of Bioscience, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy.
| | - Eloise Mastrangelo
- Biophysics Institute, CNR-IBF, Via Corti 12, 20133 Milan, Italy; Department of Bioscience, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy.
| | - Mario Milani
- Biophysics Institute, CNR-IBF, Via Corti 12, 20133 Milan, Italy; Department of Bioscience, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy.
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Brembati V, Faustini G, Longhena F, Bellucci A. Alpha synuclein post translational modifications: potential targets for Parkinson's disease therapy? Front Mol Neurosci 2023; 16:1197853. [PMID: 37305556 PMCID: PMC10248004 DOI: 10.3389/fnmol.2023.1197853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 04/27/2023] [Indexed: 06/13/2023] Open
Abstract
Parkinson's disease (PD) is the most common neurodegenerative disorder with motor symptoms. The neuropathological alterations characterizing the brain of patients with PD include the loss of dopaminergic neurons of the nigrostriatal system and the presence of Lewy bodies (LB), intraneuronal inclusions that are mainly composed of alpha-synuclein (α-Syn) fibrils. The accumulation of α-Syn in insoluble aggregates is a main neuropathological feature in PD and in other neurodegenerative diseases, including LB dementia (LBD) and multiple system atrophy (MSA), which are therefore defined as synucleinopathies. Compelling evidence supports that α-Syn post translational modifications (PTMs) such as phosphorylation, nitration, acetylation, O-GlcNAcylation, glycation, SUMOylation, ubiquitination and C-terminal cleavage, play important roles in the modulation α-Syn aggregation, solubility, turnover and membrane binding. In particular, PTMs can impact on α-Syn conformational state, thus supporting that their modulation can in turn affect α-Syn aggregation and its ability to seed further soluble α-Syn fibrillation. This review focuses on the importance of α-Syn PTMs in PD pathophysiology but also aims at highlighting their general relevance as possible biomarkers and, more importantly, as innovative therapeutic targets for synucleinopathies. In addition, we call attention to the multiple challenges that we still need to face to enable the development of novel therapeutic approaches modulating α-Syn PTMs.
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Li S, Zhang Y, Fei L, Zhang Y, Pang J, Gao W, Fan F, Xing Y, Li X. Baicalein ameliorated cerebral ischemia-reperfusion injury dependent on calpain 1/AIF pathway. Biosci Biotechnol Biochem 2021; 86:305-312. [PMID: 34935885 DOI: 10.1093/bbb/zbab222] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 12/13/2021] [Indexed: 11/13/2022]
Abstract
Cerebral ischemia-reperfusion (CIR) has become the leading cause of death and disability. Baicalein is a natural bioactive ingredient extracted from Scutellaria baicalensis Georgi and has neuroprotective activity. In our work, baicalein was found to reduce neurological deficits, brain water content, infarct area and neuronal death of rats induced by middle cerebral artery occlusion/reperfusion. In vitro, oxygen-glucose deprivation/reperfusion induced inordinate ROS production and apoptosis that could be reversed by baicalein. Our study revealed for the first time that baicalein has the potential to binds and inhibits the activity of calpain 1, thereby inhibiting AIF nuclear translocation. These findings demonstrated that baicalein protected against CIR injury via inhibiting AIF nuclear translocation by inhibiting calpain 1 activity.
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Affiliation(s)
- Shanshan Li
- School of pharmacy, Bengbu Medical College, 233030, Bengbu, Anhui, China
| | - Yaoshuai Zhang
- School of pharmacy, Bengbu Medical College, 233030, Bengbu, Anhui, China
| | - Lili Fei
- School of pharmacy, Bengbu Medical College, 233030, Bengbu, Anhui, China
| | - Yuhan Zhang
- School of pharmacy, Bengbu Medical College, 233030, Bengbu, Anhui, China
| | - Jinlong Pang
- School of pharmacy, Bengbu Medical College, 233030, Bengbu, Anhui, China
| | - Wei Gao
- School of pharmacy, Bengbu Medical College, 233030, Bengbu, Anhui, China
| | - Fangtian Fan
- School of pharmacy, Bengbu Medical College, 233030, Bengbu, Anhui, China
| | - Yadong Xing
- School of pharmacy, Bengbu Medical College, 233030, Bengbu, Anhui, China
| | - Xian Li
- School of pharmacy, Bengbu Medical College, 233030, Bengbu, Anhui, China
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W196 and the β-Hairpin Motif Modulate the Redox Switch of Conformation and the Biomolecular Interaction Network of the Apoptosis-Inducing Factor. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:6673661. [PMID: 33510840 PMCID: PMC7822688 DOI: 10.1155/2021/6673661] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/09/2020] [Accepted: 12/18/2020] [Indexed: 01/07/2023]
Abstract
The human apoptosis-inducing factor (hAIF) is a moonlight flavoprotein involved in mitochondrial respiratory complex assembly and caspase-independent programmed cell death. These functions might be modulated by its redox-linked structural transition that enables hAIF to act as a NAD(H/+) redox sensor. Upon reduction with NADH, hAIF undergoes a conformational reorganization in two specific insertions—the flexible regulatory C-loop and the 190-202 β-harpin—promoting protein dimerization and the stabilization of a long-life charge transfer complex (CTC) that modulates its monomer-dimer equilibrium and its protein interaction network in healthy mitochondria. In this regard, here, we investigated the precise function of the β-hairpin in the AIF conformation landscape related to its redox mechanism, by analyzing the role played by W196, a key residue in the interaction of this motif with the regulatory C-loop. Mutations at W196 decrease the compactness and stability of the oxidized hAIF, indicating that the β-hairpin and C-loop coupling contribute to protein stability. Kinetic studies complemented with computational simulations reveal that W196 and the β-hairpin conformation modulate the low efficiency of hAIF as NADH oxidoreductase, contributing to configure its active site in a noncompetent geometry for hydride transfer and to stabilize the CTC state by enhancing the affinity for NAD+. Finally, the β-hairpin motif contributes to define the conformation of AIF's interaction surfaces with its physiological partners. These findings improve our understanding on the molecular basis of hAIF's cellular activities, a crucial aspect for clarifying its associated pathological mechanisms and developing new molecular therapies.
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Herrmann JM, Riemer J. Apoptosis inducing factor and mitochondrial NADH dehydrogenases: redox-controlled gear boxes to switch between mitochondrial biogenesis and cell death. Biol Chem 2020; 402:289-297. [PMID: 32769219 DOI: 10.1515/hsz-2020-0254] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 08/03/2020] [Indexed: 02/07/2023]
Abstract
The mitochondrial complex I serves as entry point for NADH into the electron transport chain. In animals, fungi and plants, additional NADH dehydrogenases carry out the same electron transfer reaction, however they do not pump protons. The apoptosis inducing factor (AIF, AIFM1 in humans) is a famous member of this group as it was the first pro-apoptotic protein identified that can induce caspase-independent cell death. Recent studies on AIFM1 and the NADH dehydrogenase Nde1 of baker's yeast revealed two independent and experimentally separable activities of this class of enzymes: On the one hand, these proteins promote the functionality of mitochondrial respiration in different ways: They channel electrons into the respiratory chain and, at least in animals, promote the import of Mia40 (named MIA40 or CHCHD4 in humans) and the assembly of complex I. On the other hand, they can give rise to pro-apoptotic fragments that are released from the mitochondria to trigger cell death. Here we propose that AIFM1 and Nde1 serve as conserved redox switches which measure metabolic conditions on the mitochondrial surface and translate it into a binary life/death decision. This function is conserved among eukaryotic cells and apparently used to purge metabolically compromised cells from populations.
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Affiliation(s)
- Johannes M Herrmann
- Department of Cell Biology, University of Kaiserslautern, Erwin-Schrödinger-Strasse 13, D-67663Kaiserslautern, Germany
| | - Jan Riemer
- Department of Biochemistry, University of Cologne, Zülpicher Str. 47A, D-50674Cologne, Germany
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Tolomeo M, Nisco A, Leone P, Barile M. Development of Novel Experimental Models to Study Flavoproteome Alterations in Human Neuromuscular Diseases: The Effect of Rf Therapy. Int J Mol Sci 2020; 21:ijms21155310. [PMID: 32722651 PMCID: PMC7432027 DOI: 10.3390/ijms21155310] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 02/07/2023] Open
Abstract
Inborn errors of Riboflavin (Rf) transport and metabolism have been recently related to severe human neuromuscular disorders, as resulting in profound alteration of human flavoproteome and, therefore, of cellular bioenergetics. This explains why the interest in studying the “flavin world”, a topic which has not been intensively investigated before, has increased much over the last few years. This also prompts basic questions concerning how Rf transporters and FAD (flavin adenine dinucleotide) -forming enzymes work in humans, and how they can create a coordinated network ensuring the maintenance of intracellular flavoproteome. The concept of a coordinated cellular “flavin network”, introduced long ago studying humans suffering for Multiple Acyl-CoA Dehydrogenase Deficiency (MADD), has been, later on, addressed in model organisms and more recently in cell models. In the frame of the underlying relevance of a correct supply of Rf in humans and of a better understanding of the molecular rationale of Rf therapy in patients, this review wants to deal with theories and existing experimental models in the aim to potentiate possible therapeutic interventions in Rf-related neuromuscular diseases.
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AIF meets the CHCHD4/Mia40-dependent mitochondrial import pathway. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165746. [PMID: 32105825 DOI: 10.1016/j.bbadis.2020.165746] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 02/19/2020] [Accepted: 02/20/2020] [Indexed: 02/06/2023]
Abstract
In the mitochondria of healthy cells, Apoptosis-Inducing factor (AIF) is required for the optimal functioning of the respiratory chain machinery, mitochondrial integrity, cell survival, and proliferation. In all analysed species, it was revealed that the downregulation or depletion of AIF provokes mainly the post-transcriptional loss of respiratory chain Complex I protein subunits. Recent progress in the field has revealed that AIF fulfils its mitochondrial pro-survival function by interacting physically and functionally with CHCHD4, the evolutionarily-conserved human homolog of yeast Mia40. The redox-regulated CHCHD4/Mia40-dependent import machinery operates in the intermembrane space of the mitochondrion and controls the import of a set of nuclear-encoded cysteine-motif carrying protein substrates. In addition to their participation in the biogenesis of specific respiratory chain protein subunits, CHCHD4/Mia40 substrates are also implicated in the control of redox regulation, antioxidant response, translation, lipid homeostasis and mitochondrial ultrastructure and dynamics. Here, we discuss recent insights on the AIF/CHCHD4-dependent protein import pathway and review current data concerning the CHCHD4/Mia40 protein substrates in metazoan. Recent findings and the identification of disease-associated mutations in AIF or in specific CHCHD4/Mia40 substrates have highlighted these proteins as potential therapeutic targets in a variety of human disorders.
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Villanueva R, Romero-Tamayo S, Laplaza R, Martínez-Olivan J, Velázquez-Campoy A, Sancho J, Ferreira P, Medina M. Redox- and Ligand Binding-Dependent Conformational Ensembles in the Human Apoptosis-Inducing Factor Regulate Its Pro-Life and Cell Death Functions. Antioxid Redox Signal 2019; 30:2013-2029. [PMID: 30450916 DOI: 10.1089/ars.2018.7658] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Aims: The human apoptosis-inducing factor (hAIF) supports OXPHOS biogenesis and programmed cell death, with missense mutations producing neurodegenerative phenotypes. hAIF senses the redox environment of cellular compartments, stabilizing a charge transfer complex (CTC) dimer that modulates the protein interaction network. In this context, we aimed to evaluate the subcellular pH, CTC formation, and pathogenic mutations effects on hAIF stability, and a thermal denaturation high-throughput screening (HTS) assay to discover AIF binders. Results: Apoptotic hAIFΔ1-101 is not stable at intermembrane mitochondrial space (IMS) pH, but the 77-101 residues confer stability to the mitochondrial isoform. hAIF and its CTC populate different conformational ensembles with redox switch to the CTC producing a less stable and compact protein. The pathogenic G308E, ΔR201, and E493V mutations modulate hAIF stability; particularly, ΔR201 causes a population shift to a less stable conformation that remodels active site structure and dynamics. We have identified new molecules that modulate the hAIF reduced nicotinamide adenine dinucleotide (NADH)/oxidized nicotinamide adenine dinucleotide (NAD+) association/dissociation equilibrium and regulate its catalytic efficiency. Innovation: Biophysical methods allow evaluating the regulation of hAIF functional ensembles and to develop an HTS assay to discover small molecules that might modulate hAIF stability and activities. Conclusions: The mitochondrial soluble 54-77 portion stabilizes hAIF at the IMS pH. NADH-redox-linked conformation changes course with strong NAD+ binding and protein dimerization, but they produce a negative impact in overall hAIF stability. Loss of functionality in the R201 deletion is due to distortion of the active site architecture. We report molecules that may serve as leads in the development of hAIF bioactive compounds.
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Affiliation(s)
- Raquel Villanueva
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - Silvia Romero-Tamayo
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - Ruben Laplaza
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain.,2 Departamento de Química Física, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - Juan Martínez-Olivan
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - Adrián Velázquez-Campoy
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain.,3 Fundación ARAID, Diputación General de Aragón, Zaragoza, Spain.,4 Aragon Institute for Health Research (IIS Aragon), Zaragoza, Spain.,5 Biomedical Research Networking Centre for Liver and Digestive Diseases (CIBERehd), Madrid, Spain
| | - Javier Sancho
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain.,4 Aragon Institute for Health Research (IIS Aragon), Zaragoza, Spain
| | - Patricia Ferreira
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - Milagros Medina
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
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