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Reina S, Checchetto V. Voltage-Dependent Anion Selective Channel 3: Unraveling Structural and Functional Features of the Least Known Porin Isoform. Front Physiol 2022; 12:784867. [PMID: 35082690 PMCID: PMC8784847 DOI: 10.3389/fphys.2021.784867] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/10/2021] [Indexed: 01/31/2023] Open
Abstract
Voltage-dependent anion-selective channels (VDAC) are pore-forming proteins located in the outer mitochondrial membrane. Three isoforms are encoded by separate genes in mammals (VDAC1-3). These proteins play a crucial role in the cell, forming the primary interface between mitochondrial and cellular metabolisms. Research on the role of VDACs in the cell is a rapidly growing field, but the function of VDAC3 remains elusive. The high-sequence similarity between isoforms suggests a similar pore-forming structure. Electrophysiological analyzes revealed that VDAC3 works as a channel; however, its gating and regulation remain debated. A comparison between VDAC3 and VDAC1-2 underlines the presence of a higher number of cysteines in both isoforms 2 and 3. Recent mass spectrometry data demonstrated that the redox state of VDAC3 cysteines is evolutionarily conserved. Accordingly, these residues were always detected as totally reduced or partially oxidized, thus susceptible to disulfide exchange. The deletion of selected cysteines significantly influences the function of the channel. Some cysteine mutants of VDAC3 exhibited distinct kinetic behavior, conductance values and voltage dependence, suggesting that channel activity can be modulated by cysteine reduction/oxidation. These properties point to VDAC3 as a possible marker of redox signaling in the mitochondrial intermembrane space. Here, we summarize our current knowledge about VDAC3 predicted structure, physiological role and regulation, and possible future directions in this research field.
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Affiliation(s)
- Simona Reina
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
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Mrinalini, Koh CY, Puniamoorthy N. Rapid Genomic Evolution Drives the Diversification of Male Reproductive Genes in Dung Beetles. Genome Biol Evol 2021; 13:6329639. [PMID: 34426833 PMCID: PMC8382682 DOI: 10.1093/gbe/evab172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 11/22/2022] Open
Abstract
The molecular basis for the evolution of novel phenotypes is a central question in evolutionary biology. In recent years, dung beetles have emerged as models for novel trait evolution as they possess distinct precopulatory traits such as sexually dimorphic horns on their head and thorax. Here, we use functional and evolutionary genomics to investigate the origins and the evolution of postcopulatory reproductive traits in male dung beetles. Male ejaculates that underlie postcopulatory sexual selection are excellent candidates to study novel trait evolution as they are complex, fast evolving, and often highly divergent in insects. We assemble de novo transcriptomes of male accessory glands and testes of a widespread dung beetle, Catharsius molossus, and we perform an evolutionary analysis of closely and distantly related insect genomes. Our results show there is rapid innovation at the genomic level even among closely related dung beetles. Genomic expansion and contraction drive the divergence of male reproductive traits and their functions. The birth of scores of completely novel reproductive genes is reinforced by the recruitment of these genes for high expression in male reproductive tissues, especially in the accessory glands. We find that male accessory glands of C. molossus are specialized for secretory function and express female, egg, and embryo-related genes as well as serine protease inhibitors, whilst the testes are specialized for spermatogenesis and sperm function. Finally, we touch upon putative functions of these evolutionary novelties using structure-function analysis as these proteins bear no homology to any other known proteins.
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Affiliation(s)
- Mrinalini
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Cho Yeow Koh
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Nalini Puniamoorthy
- Department of Biological Sciences, National University of Singapore, Singapore
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Is the secret of VDAC Isoforms in their gene regulation? Characterization of human VDAC genes expression profile, promoter activity, and transcriptional regulators. Int J Mol Sci 2020; 21:ijms21197388. [PMID: 33036380 PMCID: PMC7582299 DOI: 10.3390/ijms21197388] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 02/07/2023] Open
Abstract
VDACs (voltage-dependent anion-selective channels) are pore-forming proteins of the outer mitochondrial membrane, whose permeability is primarily due to VDACs’ presence. In higher eukaryotes, three isoforms are raised during the evolution: they have the same exon–intron organization, and the proteins show the same channel-forming activity. We provide a comprehensive analysis of the three human VDAC genes (VDAC1–3), their expression profiles, promoter activity, and potential transcriptional regulators. VDAC isoforms are broadly but also specifically expressed in various human tissues at different levels, with a predominance of VDAC1 and VDAC2 over VDAC3. However, an RNA-seq cap analysis gene expression (CAGE) approach revealed a higher level of transcription activation of VDAC3 gene. We experimentally confirmed this information by reporter assay of VDACs promoter activity. Transcription factor binding sites (TFBSs) distribution in the promoters were investigated. The main regulators common to the three VDAC genes were identified as E2F-myc activator/cell cycle (E2FF), Nuclear respiratory factor 1 (NRF1), Krueppel-like transcription factors (KLFS), E-box binding factors (EBOX) transcription factor family members. All of them are involved in cell cycle and growth, proliferation, differentiation, apoptosis, and metabolism. More transcription factors specific for each VDAC gene isoform were identified, supporting the results in the literature, indicating a general role of VDAC1, as an actor of apoptosis for VDAC2, and the involvement in sex determination and development of VDAC3. For the first time, we propose a comparative analysis of human VDAC promoters to investigate their specific biological functions. Bioinformatics and experimental results confirm the essential role of the VDAC protein family in mitochondrial functionality. Moreover, insights about a specialized function and different regulation mechanisms arise for the three isoform gene.
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VDAC isoforms in mammals. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1466-76. [PMID: 22020053 DOI: 10.1016/j.bbamem.2011.10.005] [Citation(s) in RCA: 180] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 10/03/2011] [Accepted: 10/06/2011] [Indexed: 11/23/2022]
Abstract
VDACs (Voltage Dependent Anion selective Channels) are a family of pore-forming proteins discovered in the mitochondrial outer membrane. In the animal kingdom, mammals show a conserved genetic organization of the VDAC genes, corresponding to a group of three active genes. Three VDAC protein isoforms thus exist. From a historically point of view most of the data collected about this protein refer to the VDAC1 isoform, the first to be identified and also the most abundant in the organisms. In this work we compare the information available about the three VDAC isoforms, with a special emphasis upon the human proteins, here considered prototypical of the group, and we try to shed some light on specific functional roles of this apparently redundant group of proteins. A new hypothesis about the VDAC(s) involvement in ROS control is proposed. This article is part of a Special Issue entitled: VDAC structure, function, and regulation of mitochondrial metabolism.
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Sun L, Li HM, Seufferheld MJ, Walters KR, Margam VM, Jannasch A, Diaz N, Riley CP, Sun W, Li YF, Muir WM, Xie J, Wu J, Zhang F, Chen JY, Barker EL, Adamec J, Pittendrigh BR. Systems-scale analysis reveals pathways involved in cellular response to methamphetamine. PLoS One 2011; 6:e18215. [PMID: 21533132 PMCID: PMC3080363 DOI: 10.1371/journal.pone.0018215] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 02/28/2011] [Indexed: 12/20/2022] Open
Abstract
Background Methamphetamine (METH), an abused illicit drug, disrupts many cellular
processes, including energy metabolism, spermatogenesis, and maintenance of
oxidative status. However, many components of the molecular underpinnings of
METH toxicity have yet to be established. Network analyses of integrated
proteomic, transcriptomic and metabolomic data are particularly well suited
for identifying cellular responses to toxins, such as METH, which might
otherwise be obscured by the numerous and dynamic changes that are
induced. Methodology/Results We used network analyses of proteomic and transcriptomic data to evaluate
pathways in Drosophila melanogaster that are affected by
acute METH toxicity. METH exposure caused changes in the expression of genes
involved with energy metabolism, suggesting a Warburg-like effect (aerobic
glycolysis), which is normally associated with cancerous cells. Therefore,
we tested the hypothesis that carbohydrate metabolism plays an important
role in METH toxicity. In agreement with our hypothesis, we observed that
increased dietary sugars partially alleviated the toxic effects of METH. Our
systems analysis also showed that METH impacted genes and proteins known to
be associated with muscular homeostasis/contraction, maintenance of
oxidative status, oxidative phosphorylation, spermatogenesis, iron and
calcium homeostasis. Our results also provide numerous candidate genes for
the METH-induced dysfunction of spermatogenesis, which have not been
previously characterized at the molecular level. Conclusion Our results support our overall hypothesis that METH causes a toxic syndrome
that is characterized by the altered carbohydrate metabolism, dysregulation
of calcium and iron homeostasis, increased oxidative stress, and disruption
of mitochondrial functions.
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Affiliation(s)
- Lijie Sun
- Department of Entomology, University of Illinois at Urbana-Champaign,
Urbana, Illinois, United States of America
- Synthetic Biology & Bioenergy, J. Craig Venter Institute, San Diego,
California, United States of America
- Department of Entomology, Purdue University, West Lafayette, Indiana,
United States of America
| | - Hong-Mei Li
- Department of Entomology, University of Illinois at Urbana-Champaign,
Urbana, Illinois, United States of America
| | - Manfredo J. Seufferheld
- Department of Crop Sciences, University of Illinois at Urbana-Champaign,
Urbana, Illinois, United States of America
| | - Kent R. Walters
- Department of Entomology, University of Illinois at Urbana-Champaign,
Urbana, Illinois, United States of America
| | - Venu M. Margam
- Department of Entomology, Purdue University, West Lafayette, Indiana,
United States of America
| | - Amber Jannasch
- Metabolomics Profiling Facility at Bindley Bioscience Center, Purdue
University, West Lafayette, Indiana, United States of America
| | - Naomi Diaz
- Metabolomics Profiling Facility at Bindley Bioscience Center, Purdue
University, West Lafayette, Indiana, United States of America
| | - Catherine P. Riley
- Metabolomics Profiling Facility at Bindley Bioscience Center, Purdue
University, West Lafayette, Indiana, United States of America
| | - Weilin Sun
- Department of Entomology, University of Illinois at Urbana-Champaign,
Urbana, Illinois, United States of America
| | - Yueh-Feng Li
- Department of Entomology, Purdue University, West Lafayette, Indiana,
United States of America
- Chung Hwa College of Medical Technology, Jen-Te Hsiang, Tainan,
Taiwan
| | - William M. Muir
- Department of Animal Sciences, Purdue University, West Lafayette,
Indiana, United States of America
| | - Jun Xie
- Department of Statistics, Purdue University, West Lafayette, Indiana,
United States of America
| | - Jing Wu
- Department of Statistics, Carnegie Mellon University, Pittsburgh,
Pennsylvania, United States of America
| | - Fan Zhang
- School of Informatics, Indiana University, Indianapolis, Indiana, United
States of America
| | - Jake Y. Chen
- School of Informatics, Indiana University, Indianapolis, Indiana, United
States of America
| | - Eric L. Barker
- Medicinal Chemistry and Molecular Pharmacology, Purdue University, West
Lafayette, Indiana, United States of America
| | - Jiri Adamec
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska,
United States of America
| | - Barry R. Pittendrigh
- Department of Entomology, University of Illinois at Urbana-Champaign,
Urbana, Illinois, United States of America
- * E-mail:
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VDAC, a multi-functional mitochondrial protein regulating cell life and death. Mol Aspects Med 2010; 31:227-85. [PMID: 20346371 DOI: 10.1016/j.mam.2010.03.002] [Citation(s) in RCA: 530] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 03/17/2010] [Indexed: 01/22/2023]
Abstract
Research over the past decade has extended the prevailing view of the mitochondrion to include functions well beyond the generation of cellular energy. It is now recognized that mitochondria play a crucial role in cell signaling events, inter-organellar communication, aging, cell proliferation, diseases and cell death. Thus, mitochondria play a central role in the regulation of apoptosis (programmed cell death) and serve as the venue for cellular decisions leading to cell life or death. One of the mitochondrial proteins controlling cell life and death is the voltage-dependent anion channel (VDAC), also known as mitochondrial porin. VDAC, located in the mitochondrial outer membrane, functions as gatekeeper for the entry and exit of mitochondrial metabolites, thereby controlling cross-talk between mitochondria and the rest of the cell. VDAC is also a key player in mitochondria-mediated apoptosis. Thus, in addition to regulating the metabolic and energetic functions of mitochondria, VDAC appears to be a convergence point for a variety of cell survival and cell death signals mediated by its association with various ligands and proteins. In this article, we review what is known about the VDAC channel in terms of its structure, relevance to ATP rationing, Ca(2+) homeostasis, protection against oxidative stress, regulation of apoptosis, involvement in several diseases and its role in the action of different drugs. In light of our recent findings and the recently solved NMR- and crystallography-based 3D structures of VDAC1, the focus of this review will be on the central role of VDAC in cell life and death, addressing VDAC function in the regulation of mitochondria-mediated apoptosis with an emphasis on structure-function relations. Understanding structure-function relationships of VDAC is critical for deciphering how this channel can perform such a variety of functions, all important for cell life and death. This review also provides insight into the potential of VDAC1 as a rational target for new therapeutics.
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Abstract
The eukaryotic VDAC (voltage-dependent anion channel) is a pore-forming protein originally discovered in the outer membrane of mitochondria. It has been established as a key player in mitochondrial metabolism and ion signalling. In addition, in recent years, it has also been proposed that VDAC is present in extra-mitochondrial membranes, and it has been related to cytoskeletal structures. However, little is known about the presence and intracellular localization of VDAC subtypes in mammalian gametes. In the present study, we confirm the synthesis of VDAC1 and 2 subtypes in GV (germinal vesicle) and MII (meiosis II) stage porcine oocytes as well as their protein expression. A shift in the abundance of immunoreactive 32 kDa VDAC protein between GV and MII stage oocytes was observed with anti-VDAC2 antibody. Furthermore, subcellular localization by confocal laser microscopy demonstrated fluorescent labelling of VDAC1 over the entire oocyte surface, suggesting the presence of VDAC1 in the porcine oocyte plasma membrane and around the cortical area. Anti-VDAC2 immunostaining yielded ring-like clusters of structures distributed on the cortical area in some GV, but not in MII, stage oocytes. These results are the first data obtained for VDAC in mammalian female gametes and provide the basis for studying protein–protein interactions, distribution and possible functions of VDAC subtypes during maturation and fertilization of mammalian oocytes.
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