scholarly journals The FtsHi Enzymes of Arabidopsis thaliana: Pseudo-Proteases with an Important Function

2021 ◽  
Vol 22 (11) ◽  
pp. 5917
Author(s):  
Laxmi S. Mishra ◽  
Christiane Funk
Keyword(s):  
Arabidopsis Thaliana ◽  
Protein Import ◽  
Model Organism ◽  
Vital Role ◽  
Binding Motif ◽  
Aaa Atpase ◽  
Seed Growth ◽  
Membrane Bound ◽  
And Oxidative Stress ◽  
Zinc Binding Motif

FtsH metalloproteases found in eubacteria, animals, and plants are well-known for their vital role in the maintenance and proteolysis of membrane proteins. Their location is restricted to organelles of endosymbiotic origin, the chloroplasts, and mitochondria. In the model organism Arabidopsis thaliana, there are 17 membrane-bound FtsH proteases containing an AAA+ (ATPase associated with various cellular activities) and a Zn2+ metalloprotease domain. However, in five of those, the zinc-binding motif HEXXH is either mutated (FtsHi1, 2, 4, 5) or completely missing (FtsHi3), rendering these enzymes presumably inactive in proteolysis. Still, homozygous null mutants of the pseudo-proteases FtsHi1, 2, 4, 5 are embryo-lethal. Homozygous ftshi3 or a weak point mutant in FTSHi1 are affected in overall plant growth and development. This review will focus on the findings concerning the FtsHi pseudo-proteases and their involvement in protein import, leading to consequences in embryogenesis, seed growth, chloroplast, and leaf development and oxidative stress management.

ATP-driven processes of peroxisomal matrix protein import

2017 ◽  
Vol 398 (5-6) ◽  
pp. 607-624 ◽  
Author(s):  
Daniel P. Schwerter ◽  
Immanuel Grimm ◽  
Harald W. Platta ◽  
Ralf Erdmann
Keyword(s):  
Matrix Protein ◽  
Protein Import ◽  
Atp Hydrolysis ◽  
Current Knowledge ◽  
Model Organism ◽  
Peroxisomal Membrane ◽  
Dual Localization ◽  
Import Receptors ◽  
Membrane Bound ◽  
Atp Binding And Hydrolysis

Abstract In peroxisomal matrix protein import two processes directly depend on the binding and hydrolysis of ATP, both taking place at the late steps of the peroxisomal import cycle. First, ATP hydrolysis is required to initiate a ubiquitin-transfer cascade to modify the import (co-)receptors. These receptors display a dual localization in the cytosol and at the peroxisomal membrane, whereas only the membrane bound fraction receives the ubiquitin modification. The second ATP-dependent process of the import cycle is carried out by the two AAA+-proteins Pex1p and Pex6p. These ATPases form a heterohexameric complex, which is recruited to the peroxisomal import machinery by the membrane anchor protein Pex15p. The Pex1p/Pex6p complex recognizes the ubiquitinated import receptors, pulls them out of the membrane and releases them into the cytosol. There the deubiquitinated receptors are provided for further rounds of import. ATP binding and hydrolysis are required for Pex1p/Pex6p complex formation and receptor export. In this review, we summarize the current knowledge on the peroxisomal import cascade. In particular, we will focus on the ATP-dependent processes, which are so far best understood in the model organism Saccharomyces cerevisiae.

Multiple haem lyase genes indicate substrate specificity in cytochrome c biogenesis

2006 ◽  
Vol 34 (1) ◽  
pp. 146-149 ◽  
Author(s):  
S. Hartshorne ◽  
D.J. Richardson ◽  
J. Simon
Keyword(s):  
Cytochrome C ◽  
Model Organism ◽  
Vital Role ◽  
Covalent Attachment ◽  
Binding Motif ◽  
Binding Motifs ◽  
Cytochrome C Biogenesis ◽  
Multiple Copies ◽  
Energy Conserving ◽  
Eukaryotic Organisms

c-Type cytochromes are a widespread class of proteins that play a vital role in the energy-conserving metabolism of prokaryotic and eukaryotic organisms. The key event in cytochrome c biogenesis is the covalent attachment of the haem cofactor to two (or rarely one) cysteine residues arranged in a haem c-binding motif such as CX2–4CH, CXXCK or X3CH. This reaction is catalysed by the membrane-bound enzyme CCHL (cytochrome c haem lyase). Different CCHLs have been described and some of them are dedicated to distinct haem c-binding motifs of cytochromes that are encoded in the vicinity of the respective CCHL gene. Various bacterial genomes contain multiple copies of CCHL-encoding genes, suggesting the presence of non-conventional or even as yet unrecognized haem c-binding motifs. This assumption is exemplified in the present study using the proteobacterium Wolinella succinogenes as a model organism whose genome encodes three CCHL isoenzymes. The discovery of a novel conserved multihaem cytochrome c (MccA) is described.

Mercury Exposure and Endothelial Dysfunction

2015 ◽  
Vol 34 (4) ◽  
pp. 300-307 ◽  
Author(s):  
Swati Omanwar ◽  
M. Fahim
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Endothelial Dysfunction ◽  
Vascular Endothelium ◽  
Circulatory System ◽  
Vital Role ◽  
Mercury Exposure ◽  
And Function ◽  
The Impact ◽  
And Oxidative Stress

Vascular endothelium plays a vital role in the organization and function of the blood vessel and maintains homeostasis of the circulatory system and normal arterial function. Functional disruption of the endothelium is recognized as the beginning event that triggers the development of consequent cardiovascular disease (CVD) including atherosclerosis and coronary heart disease. There is a growing data associating mercury exposure with endothelial dysfunction and higher risk of CVD. This review explores and evaluates the impact of mercury exposure on CVD and endothelial function, highlighting the interplay of nitric oxide and oxidative stress.

Effect of mutations in a zinc-binding domain of yeast RNA polymerase C (III) on enzyme function and subunit association

1992 ◽  
Vol 12 (3) ◽  
pp. 1087-1095
Author(s):  
M Werner ◽  
S Hermann-Le Denmat ◽  
I Treich ◽  
A Sentenac ◽  
P Thuriaux
Keyword(s):  
Rna Polymerase ◽  
Zinc Binding ◽  
Enzyme Function ◽  
Directed Mutagenesis ◽  
Binding Motif ◽  
Zinc Ions ◽  
Amino Terminal ◽  
Zinc Binding Domain ◽  
Zinc Binding Motif

The conserved amino-terminal region of the largest subunit of yeast RNA polymerase C is capable of binding zinc ions in vitro. By oligonucleotide-directed mutagenesis, we show that the putative zinc-binding motif CX2CX6-12CXGHXGX24-37CX2C, present in the largest subunit of all eukaryotic and archaebacterial RNA polymerases, is essential for the function of RNA polymerase C. All mutations in the invariant cysteine and histidine residues conferred a lethal phenotype. We also obtained two conditional thermosensitive mutants affecting this region. One of these produced a form of RNA polymerase C which was thermosensitive and unstable in vitro. This instability was correlated with the loss of three of the subunits which are specific to RNA polymerase C: C82, C34, and C31.

scholarly journals Knockout and Overexpression of Pyrroloquinoline Quinone Biosynthetic Genes in Gluconobacter oxydans 621H

2006 ◽  
Vol 188 (21) ◽  
pp. 7668-7676 ◽  
Author(s):  
Tina Hölscher ◽  
Helmut Görisch
Keyword(s):  
Energy Source ◽  
Wild Type Strain ◽  
Gluconobacter Oxydans ◽  
Analysis Data ◽  
Pyrroloquinoline Quinone ◽  
Vital Role ◽  
Reverse Transcription Pcr ◽  
Membrane Bound ◽  
Pqq Biosynthesis

ABSTRACT In Gluconobacter oxydans, pyrroloquinoline quinone (PQQ) serves as the cofactor for various membrane-bound dehydrogenases that oxidize sugars and alcohols in the periplasm. Proteins for the biosynthesis of PQQ are encoded by the pqqABCDE gene cluster. Our reverse transcription-PCR and promoter analysis data indicated that the pqqA promoter represents the only promoter within the pqqABCDE cluster of G. oxydans 621H. PQQ overproduction in G. oxydans was achieved by transformation with the plasmid-carried pqqA gene or the complete pqqABCDE cluster. A G. oxydans mutant unable to produce PQQ was obtained by site-directed disruption of the pqqA gene. In contrast to the wild-type strain, the pqqA mutant did not grow with d-mannitol, d-glucose, or glycerol as the sole energy source, showing that in G. oxydans 621H, PQQ is essential for growth with these substrates. Growth of the pqqA mutant, however, was found with d-gluconate as the energy source. The growth behavior of the pqqA mutant correlated with the presence or absence of the respective PQQ-dependent membrane-bound dehydrogenase activities, demonstrating the vital role of these enzymes in G. oxydans metabolism. A different PQQ-deficient mutant was generated by Tn5 transposon mutagenesis. This mutant showed a defect in a gene with high homology to the Escherichia coli tldD gene, which encodes a peptidase. Our results indicate that the tldD gene in G. oxydans 621H is involved in PQQ biosynthesis, possibly with a similar function to that of the pqqF genes found in other PQQ-synthesizing bacteria.

scholarly journals Phosphonamidates are the first phosphorus-based zinc binding motif to show inhibition of β-class carbonic anhydrases from bacteria, fungi, and protozoa

2019 ◽  
Vol 35 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Siham A. Alissa ◽  
Hanan A. Alghulikah ◽  
Zeid A. Alothman ◽  
Sameh M. Osman ◽  
Sonia Del Prete ◽  
...  
Keyword(s):  
Zinc Binding ◽  
Binding Motif ◽  
Carbonic Anhydrases ◽  
Zinc Binding Motif

Conformational dynamics and allosteric effect modulated by the unique zinc-binding motif in class IIa HDACs

2019 ◽  
Vol 21 (23) ◽  
pp. 12173-12183 ◽  
Author(s):  
Huawei Liu ◽  
Fan Zhang ◽  
Kai Wang ◽  
Xiaowen Tang ◽  
Ruibo Wu
Keyword(s):  
Histone Deacetylases ◽  
Conformational Dynamics ◽  
Zinc Binding ◽  
Binding Motif ◽  
Allosteric Effect ◽  
Class Iia Hdacs ◽  
Zinc Binding Motif

Class IIa histone deacetylases (HDACs) have been considered as potential targets for the treatment of several diseases.

scholarly journals Fission Yeast Polarization: Modeling Cdc42 Oscillations, Symmetry Breaking, and Zones of Activation and Inhibition

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1769 ◽  
Author(s):  
Bita Khalili ◽  
Hailey D. Lovelace ◽  
David M. Rutkowski ◽  
Danielle Holz ◽  
Dimitrios Vavylonis
Keyword(s):  
Fission Yeast ◽  
Model Organism ◽  
Reaction Diffusion ◽  
Small Gtpases ◽  
Membrane Diffusion ◽  
Gtpase Activating Proteins ◽  
Reaction Diffusion Model ◽  
Membrane Bound ◽  
Negative Feedbacks ◽  
Positive And Negative Feedbacks

Cells polarize for growth, motion, or mating through regulation of membrane-bound small GTPases between active GTP-bound and inactive GDP-bound forms. Activators (GEFs, GTP exchange factors) and inhibitors (GAPs, GTPase activating proteins) provide positive and negative feedbacks. We show that a reaction–diffusion model on a curved surface accounts for key features of polarization of model organism fission yeast. The model implements Cdc42 membrane diffusion using measured values for diffusion coefficients and dissociation rates and assumes a limiting GEF pool (proteins Gef1 and Scd1), as in prior models for budding yeast. The model includes two types of GAPs, one representing tip-localized GAPs, such as Rga3; and one representing side-localized GAPs, such as Rga4 and Rga6, that we assume switch between fast and slow diffusing states. After adjustment of unknown rate constants, the model reproduces active Cdc42 zones at cell tips and the pattern of GEF and GAP localization at cell tips and sides. The model reproduces observed tip-to-tip oscillations with periods of the order of several minutes, as well as asymmetric to symmetric oscillations transitions (corresponding to NETO “new end take off”), assuming the limiting GEF amount increases with cell size.

scholarly journals RNA-binding protein 39: a promising therapeutic target for cancer

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Caipeng Xu ◽  
Xiaohua Chen ◽  
Xuetian Zhang ◽  
Dapeng Zhao ◽  
Zhihui Dou ◽  
...  
Keyword(s):  
Clinical Application ◽  
Rna Binding ◽  
Drug Research ◽  
Protein Translation ◽  
Vital Role ◽  
Binding Motif ◽  
Promising Therapeutic Target ◽  
Key Factor ◽  
Mrna And Protein Expression ◽  
Development Prospects

AbstractRNA-binding motif protein 39 (RBM39), as a key factor in tumor-targeted mRNA and protein expression, not only plays a vital role in tumorigenesis, but also has broad development prospects in clinical treatment and drug research. Moreover, since RBM39 was identified as a target of sulfonamides, it has played a key role in the emerging field of molecule drug development. Hence, it is of great significance to study the interaction between RBM39 and tumors and the clinical application of drug-targeted therapy. In this paper, we describe the possible multi-level regulation of RBM39, including gene transcription, protein translation, and alternative splicing. Importantly, the molecular function of RBM39 as an important splicing factor in most common tumors is systematically outlined. Furthermore, we briefly introduce RBM39’s tumor-targeted drug research and its clinical application, hoping to give reference significance for the molecular mechanism of RBM39 in tumors, and provide reliable ideas for in-depth research for future therapeutic strategies.

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