Molecular interactions of Bipolaris maydis T-toxin and maize

1995 ◽  
Vol 73 (S1) ◽  
pp. 483-489 ◽  
Author(s):  
Charles S. Levings III ◽  
David M. Rhoads ◽  
James N. Siedow
Keyword(s):  
Male Sterility ◽  
Mitochondrial Membrane ◽  
Fungal Pathogens ◽  
Mitochondrial Gene ◽  
Site Directed Mutagenesis ◽  
Cross Linking ◽  
Male Sterile ◽  
Inner Mitochondrial Membrane ◽  
Bipolaris Maydis ◽  
Maize Cytoplasmic Male Sterility

The toxins (T-toxins) produced by the fungal pathogens Bipolaris maydis race T (BmT) and Phyllosticta maydis (Pm) target the mitochondrial receptor, URF13, in maize (Zea mays L.) plants containing the Texas male-sterile cytoplasm (cms-T). URF13, a 13-kDa protein, is the product of the maize mitochondrial gene T-urf13, which is found only in the mitochondrial genome of cms-T maize and is thought to be responsible for cytoplasmically inherited male sterility and disease susceptibility. Pm-toxin binds specifically to URF13 in a cooperative manner, and Pm- and BmT-toxins compete for the same, or overlapping, binding sites. The binding of T-toxin to URF13 causes rapid permcabilization of the inner mitochondrial membrane, which results in leakage of NAD+ and other ions from the matrix. A pore consisting of at least six transmembrane α-helices is required for NAD+ leakage. Cross-linking experiments showed that URF13 oligomers are present in the mitochondrial membrane. A model of the secondary structure of URF13 proposes that each monomer contains three transmembrane α-helices. Studies combining site-directed mutagenesis and chemical cross-linking of URF13 expressed by Escherichia coli cells indicate that the oligomers are composed of a central core of helices II that line the center of the URF13 pores. Key words: maize cytoplasmic male sterility, URF13, mitochondrial pores, T-toxin receptor, Bipolaris maydis race T, Phyllosticta maydis, Helminthosporium maydis.

Translocation of Adenine Nucleotides in the Mitochondria of Male Sterile and Male Fertile Sorghum

1993 ◽  
Vol 48 (9-10) ◽  
pp. 795-798 ◽  
Author(s):  
J. Arora ◽  
P. Nath ◽  
P. V. Sane
Keyword(s):  
Male Sterility ◽  
Mitochondrial Membrane ◽  
Adenine Nucleotides ◽  
Male Sterile ◽  
Male Sterile Line ◽  
Chondrial Membrane

Abstract The translocation of ATP from the inside to the outside of the mitochondrial membrane has been studied in a male sterile (2219 A) and a male fertile (2219 B) line of sorghum. The translocation of ATP was found to be substantially lower in case of mitochondria from the male sterile line. The affinity of adenine nucleotides to the translocator proteins of the mito­ chondrial membrane was found to be almost one half in case of 2219 A as compared to 2219 B when the Km for ATP-ADP was determined by two different assays. It is proposed that the inadequate supply of ATP in the cytosol resulting from its inefficient translocation may con­ tribute to the male sterility in this line.

scholarly journals Mitochondrial metabolite carrier family, topology, structure and functional properties: an overview.

1996 ◽  
Vol 43 (2) ◽  
pp. 349-360 ◽  
Author(s):  
F E Sluse
Keyword(s):  
Mitochondrial Membrane ◽  
Molecular Mechanisms ◽  
Kinetic Mechanism ◽  
Transport Processes ◽  
Site Directed Mutagenesis ◽  
Mitochondrial Matrix ◽  
Chemiosmotic Theory ◽  
Inner Mitochondrial Membrane ◽  
The Third ◽  
Function Relationship

A set of metabolite carriers operates the traffic of numerous molecules consumed or produced in mitochondrial matrix and/or cytosolic compartments. As their existence has been predicted by the chemiosmotic theory, the first challenge, in the late sixties, was to prove their presence in the inner mitochondrial membrane and to describe the various transports carried out. The second challenge was to understand their mechanisms by the kinetic approach in intact mitochondria (seventies). The third challenge (late seventies-eighties) was to isolate and to reconstitute the carriers in liposomes in order to characterize the proteins and to establish the concept of a structural and a functional family as well as some structure-function relationship with the help of primary sequences. Genetics, molecular biology and genomic sequencing bring the fourth challenge (nineties): a raising number of putative carriers becomes known only by their primary sequences but their functions have to be discovered. The actual challenge of the future is the elucidation of the ternary structure of carrier proteins that together with site-directed mutagenesis and kinetic mechanism will permit to advance in the understanding of molecular mechanisms of transport processes.

scholarly journals Evidence of the Proximity of ATP Synthase Subunits 6 (a) in the Inner Mitochondrial Membrane and in the Supramolecular Forms of Saccharomyces cerevisiae ATP Synthase

2011 ◽  
Vol 286 (41) ◽  
pp. 35477-35484 ◽  
Author(s):  
Jean Velours ◽  
Claire Stines-Chaumeil ◽  
Johan Habersetzer ◽  
Stéphane Chaignepain ◽  
Alain Dautant ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Atp Synthase ◽  
Mitochondrial Membrane ◽  
Transmembrane Helix ◽  
Disulfide Bridge ◽  
Cross Linking ◽  
Null Mutant ◽  
Terminal Part ◽  
Inner Mitochondrial Membrane ◽  
Membrane Spanning

The involvement of subunit 6 (a) in the interface between yeast ATP synthase monomers has been highlighted. Based on the formation of a disulfide bond and using the unique cysteine 23 as target, we show that two subunits 6 are close in the inner mitochondrial membrane and in the solubilized supramolecular forms of the yeast ATP synthase. In a null mutant devoid of supernumerary subunits e and g that are involved in the stabilization of ATP synthase dimers, ATP synthase monomers are close enough in the inner mitochondrial membrane to make a disulfide bridge between their subunits 6, and this proximity is maintained in detergent extract containing this enzyme. The cross-linking of cysteine 23 located in the N-terminal part of the first transmembrane helix of subunit 6 suggests that this membrane-spanning segment is in contact with its counterpart belonging to the ATP synthase monomer that faces it and participates in the monomer-monomer interface.

scholarly journals Rbfox2 is Critical for Maintaining Alternative Polyadenylation and Mitochondrial Health in Myoblasts

2020 ◽  
Author(s):  
Jun Cao ◽  
Elizabeth Jaworski ◽  
Kempaiah Rayavara ◽  
KarryAnne Belanger ◽  
Amanda Sooter ◽  
...  
Keyword(s):  
Mitochondrial Membrane ◽  
Rna Binding ◽  
Heart Diseases ◽  
Mitochondrial Gene ◽  
Alternative Polyadenylation ◽  
Mitochondrial Genes ◽  
Fine Tuning ◽  
Inner Mitochondrial Membrane ◽  
Altered Expression ◽  
And Function

ABSTRACTThe RNA binding protein RBFOX2 is linked to heart and skeletal muscle diseases; yet, RBFOX2-regulated RNA networks have not been systematically identified. Although RBFOX2 has a well-known function in alternative splicing (AS), it is unclear whether RBFOX2 has other roles in RNA metabolism that affect gene expression and function. Utilizing state of the art techniques Poly(A)-ClickSeq (PAC-seq) and nanopore cDNA sequencing, we revealed a new role for RBFOX2 in fine tuning alternative polyadenylation (APA) of pre-mRNAs in myoblasts. We found that depletion of RBFOX2 altered expression of mitochondrial genes. We identified the mitochondrial gene Slc25a4 gene that transports ATP/ADP across inner mitochondrial membrane as a target of RBFOX2. Dissecting how RBFOX2 affects Slc25a4 APA uncovered that RBFOX2 binding motifs near the distal polyadenylation site (PAS) are critical for expression of Slc25a4. Consistent with changes in expression of mitochondrial genes, loss of RBFOX2 altered mitochondrial membrane potential and induced mitochondrial swelling. Our results unveiled a novel role for RBFOX2 in maintaining APA decisions and expression of mitochondrial genes in myoblasts relevant to heart diseases.

scholarly journals Intraspecific variations of the cytoplasmic male sterility genes orf108 and orf117 in Brassica maurorum and Moricandia arvensis, and the specificity of the mRNA processing

Genome ◽  
2021 ◽  
Author(s):  
Hiroshi Yamagishi ◽  
Ayako Hashimoto ◽  
Asumi Fukunaga ◽  
Sang Woo Bang ◽  
Toru Terachi
Keyword(s):  
Cytoplasmic Male Sterility ◽  
Male Sterility ◽  
Dna Sequences ◽  
Wild Species ◽  
Polymerase Chain Reaction Amplification ◽  
Mitochondrial Gene ◽  
Male Sterile ◽  
Intraspecific Variations ◽  
Moricandia Arvensis ◽  
Sterility Genes

The mitochondrial gene <i>orf108</i> co-transcribed with <i>atp1</i> and causes cytoplasmic male sterility in <i>Brassica</i> crops, is widely distributed across wild species and genera of <i>Brassicaceae</i>. However, intraspecific variations in the presence of <i>orf108</i> have not yet been studied, and the mechanisms for the wide distribution of the gene remain unclear. We analyzed the presence and sequence variations of <i>orf108</i> in two wild species, <i>Brassica maurorum</i> and <i>Moricandia arvensis</i>. After polymerase chain reaction amplification of the 5′ region of <i>atp1</i> and the coding sequence of <i>orf108</i>, we determined the DNA sequences. <i>B. maurorum</i> and <i>M. arvensis</i> showed variations for the presence of <i>orf108</i> or <i>orf117</i> (<i>orf108<sup>V117</sup></i>) both between and within accessions, and were not fixed to the mitochondrial type having the male sterile genes. Sequencing of the amplicons clarified that <i>B. maurorum</i> has <i>orf108<sup>V117</sup></i> instead of <i>orf108</i>. Sequencing also indicated mitochondrial heteroplasmy in the two species; particularly, in <i>B. maurorum</i>, one plant possessed both the <i>orf108</i> and <i>orf108<sup>V117</sup></i> sequences. The results suggested that substoichiometric shifting of the mitochondrial genomes leads to the acquisition or loss of <i>orf108</i>. Furthermore, fertility restorer genes of the two species were involved in the processing of the mRNA of the male sterility genes at different sites.

scholarly journals Mitochondrial protein interaction landscape of SS-31

2019 ◽  
Author(s):  
Juan D. Chavez ◽  
Xiaoting Tang ◽  
Matthew D. Campbell ◽  
Gustavo Reyes ◽  
Philip A. Kramer ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Protein Interaction ◽  
Mitochondrial Function ◽  
Mitochondrial Membrane ◽  
Cross Linking ◽  
Pharmacological Effects ◽  
Inner Mitochondrial Membrane ◽  
Atp Production ◽  
Mechanistic Insight ◽  
Chemical Cross Linking

AbstractMitochondrial dysfunction underlies the etiology of a broad spectrum of diseases including heart disease, cancer, neurodegenerative diseases, and the general aging process. Therapeutics that restore healthy mitochondrial function hold promise for treatment of these conditions. The synthetic tetrapeptide, elamipretide (SS-31), improves mitochondrial function, but mechanistic details of its pharmacological effects are unknown. Reportedly, SS-31 primarily interacts with the phospholipid cardiolipin in the inner mitochondrial membrane. Here we utilize chemical cross-linking with mass spectrometry to identify protein interactors of SS-31 in mitochondria. The SS-31-interacting proteins, all known cardiolipin binders, fall into two groups, those involved in ATP production through the oxidative phosphorylation pathway and those involved in 2-oxoglutarate metabolic processes. Residues cross-linked with SS-31 reveal binding regions that in many cases, are proximal to cardiolipin-protein interacting regions. These results offer the first glimpse of the protein interaction landscape of SS-31 and provide new mechanistic insight relevant to SS-31 mitochondrial therapy.Significance StatementSS-31 is a synthetic peptide that improves mitochondrial function and is currently undergoing clinical trials for treatments of heart failure, primary mitochondrial myopathy, and other mitochondrial diseases. SS-31 interacts with cardiolipin which is abundant in the inner mitochondrial membrane, but mechanistic details of its pharmacological effects are unknown. Here we apply a novel chemical cross-linking/mass spectrometry method to provide the first direct evidence for specific interactions between SS-31 and mitochondrial proteins. The identified SS-31 interactors are functional components in ATP production and 2-oxoglutarate metabolism and signaling, consistent with improved mitochondrial function resultant from SS-31 treatment. These results offer the first glimpse of the protein interaction landscape of SS-31 and provide new mechanistic insight relevant to SS-31 mitochondrial therapy.

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