scholarly journals SecA defects are accompanied by dysregulation of MukB, DNA gyrase, chromosome partitioning and DNA superhelicity in Escherichia coli

Microbiology ◽  
2014 ◽  
Vol 160 (8) ◽  
pp. 1648-1658 ◽  
Author(s):  
Shun Adachi ◽  
Yasuhiro Murakawa ◽  
Sota Hiraga
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Molecular Mechanisms ◽  
Protein Translocation ◽  
Genetic Interaction ◽  
Acyl Carrier Protein ◽  
Dna Gyrase ◽  
Spatial Regulation ◽  
Chromosome Partitioning ◽  
Structural Maintenance Of Chromosomes

Spatial regulation of nucleoids and chromosome-partitioning proteins is important for proper chromosome partitioning in Escherichia coli. However, the underlying molecular mechanisms are unknown. In the present work, we showed that mutation or chemical perturbation of secretory A (SecA), an ATPase component of the membrane protein translocation machinery, SecY, a component of the membrane protein translocation channel and acyl carrier protein P (AcpP), which binds to SecA and MukB, a functional homologue of structural maintenance of chromosomes protein (SMC), resulted in a defect in chromosome partitioning. We further showed that SecA is essential for proper positioning of the oriC DNA region, decatenation and maintenance of superhelicity of DNA. Genetic interaction studies revealed that the topological abnormality observed in the secA mutant was due to combined inhibitory effects of defects in MukB, DNA gyrase and Topo IV, suggesting a role for the membrane protein translocation machinery in chromosome partitioning and/or structural maintenance of chromosomes.

scholarly journals Dynamic nature of SecA and its associated proteins in Escherichia coli

2015 ◽  
Vol 6 ◽  
Author(s):  
Shun Adachi ◽  
Yasuhiro Murakawa ◽  
Sota Hiraga
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Chromosome Segregation ◽  
Protein Translocation ◽  
Three Dimensional ◽  
Time Lapse ◽  
Topoisomerase Iv ◽  
Chromosome Partitioning ◽  
Functional Homolog ◽  
Associated Proteins

Mechanical properties such as physical constraint and pushing of chromosomes are thought to be important for chromosome segregation in Escherichia coli and it could be mediated by a hypothetical molecular “tether.” However, the actual tether that mediates these features is not known. We previously described that SecA (Secretory A) and Secretory Y (SecY), components of the membrane protein translocation machinery, and AcpP (Acyl carrier protein P) were involved in chromosome segregation and homeostasis of DNA topology. In the present work, we performed three-dimensional deconvolution of microscopic images and time-lapse experiments of these proteins together with MukB and DNA topoisomerases, and found that these proteins embraced the structures of tortuous nucleoids with condensed regions. Notably, SecA, SecY, and AcpP dynamically localized in cells, which was interdependent on each other requiring the ATPase activity of SecA. Our findings imply that the membrane protein translocation machinery plays a role in the maintenance of proper chromosome partitioning, possibly through “tethering” of MukB [a functional homolog of structural maintenance of chromosomes (SMC) proteins], DNA gyrase, DNA topoisomerase IV, and SeqA (Sequestration A).

Glycolipozyme membrane protein integrase (MPIase): recent data

2014 ◽  
Vol 5 (5) ◽  
pp. 429-438 ◽  
Author(s):  
Ken-ichi Nishiyama ◽  
Keiko Shimamoto
Keyword(s):  
Escherichia Coli ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Structure Determination ◽  
Molecular Chaperone ◽  
Molecular Mechanisms ◽  
Cytoplasmic Membrane ◽  
Amino Sugars ◽  
Glycan Chain ◽  
Preprotein Translocation

AbstractA novel factor for membrane protein integration, from the cytoplasmic membrane of Escherichia coli, named MPIase (membrane protein integrase), has recently been identified and characterized. MPIase was revealed to be essential for the membrane integration of a subset of membrane proteins, despite that such integration reactions have been, thus far, thought to occur spontaneously. The structure determination study revealed that MPIase is a novel glycolipid comprising a glycan chain with three N-acetylated amino sugars connected to diacylglycerol through a pyrophosphate linker. As MPIase catalyzes membrane protein integration, we propose that MPIase is a glycolipozyme on the basis of its enzyme-like function. The glycan chain exhibits a molecular chaperone-like function by directly interacting with substrate membrane proteins. Moreover, MPIase also affects the dimer structure of SecYEG, a translocon, thereby significantly stimulating preprotein translocation. The molecular mechanisms of MPIase functions will be outlined.

scholarly journals Acyl Carrier Protein is essential for MukBEF action in Escherichia coli chromosome organization-segregation

2021 ◽  
Author(s):  
Josh Prince ◽  
Jani Bolla ◽  
Gemma Fisher ◽  
Jarno Makela ◽  
Majorie Fournier ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acyl Carrier Protein ◽  
Coiled Coil ◽  
Acid Synthesis ◽  
Chromosome Organization ◽  
Carrier Protein ◽  
Accessory Proteins ◽  
Structural Maintenance Of Chromosomes ◽  
Smc Proteins

Abstract Structural Maintenance of Chromosomes (SMC) complexes contribute ubiquitously to chromosome organization-segregation. SMC proteins have a conserved architecture, with a dimerization hinge and an ATPase head domain separated by a long antiparallel intramolecular coiled-coil. Dimeric SMC proteins interact with essential accessory proteins, kleisins that bridge the two subunits of an SMC dimer, and HAWK/KITE accessory proteins that interact with kleisins. The ATPase activity of the Escherichia coli SMC protein, MukB, is essential for in vivo function and is regulated by interactions with its dimeric kleisin, MukF, and KITE, MukE. Here we demonstrate that, in addition, MukB interacts with Acyl Carrier Protein (AcpP) that has essential functions in fatty acid synthesis. We characterize the AcpP interaction site at the joint of the MukB coiled-coil and show that the interaction is essential for MukB ATPase and for MukBEF function in vivo. Therefore, AcpP is an essential co-factor for MukBEF action in chromosome organization-segregation.

Secretion of immunodominant membrane protein from onion yellows phytoplasma through the Sec protein-translocation system in Escherichia coli

Microbiology ◽  
2004 ◽  
Vol 150 (1) ◽  
pp. 135-142 ◽  
Author(s):  
Shigeyuki Kakizawa ◽  
Kenro Oshima ◽  
Hisashi Nishigawa ◽  
Hee-Young Jung ◽  
Wei Wei ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Protein Translocation

scholarly journals Tip Loci: Six Chlamydomonas Nuclear Suppressors That Permit the Translocation of Proteins with Mutant Thylakoid Signal Sequences

Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1293-1301
Author(s):  
Karen K Bernd ◽  
Bruce D Kohorn
Keyword(s):  
Membrane Protein ◽  
Protein Translocation ◽  
Genetic Interaction ◽  
Signal Sequence ◽  
Cytochrome F ◽  
Signal Sequences ◽  
Photoautotrophic Growth ◽  
Thylakoid Protein ◽  
Allele Specific ◽  
Nuclear Loci

Abstract Mutations within the signal sequence of cytochrome f (cytf) in Chlamydomonas inhibit thylakoid membrane protein translocation and render cells nonphotosynthetic. Twenty-seven suppressors of the mutant signal sequences were selected for their ability to restore photoautotrophic growth and these describe six nuclear loci named tip1 through 6 for thylakoid insertion protein. The tip mutations restore the translocation of cytf and are not allele specific, as they suppress a number of different cytf signal sequence mutations. Tip5 and 2 may act early in cytf translocation, while Tip1, 3, 4, and 6 are engaged later. The tip mutations have no phenotype in the absence of a signal sequence mutation and there is genetic interaction between tip4, and tip5 suggesting an interaction of their encoded proteins. As there is overlap in the energetic, biochemical and genetic requirements for the translocation of nuclear and chloroplast-encoded thylakoid proteins, the tip mutations likely identify components of a general thylakoid protein translocation apparatus.

scholarly journals Peroxisome assembly: matrix and membrane protein biogenesis

2011 ◽  
Vol 193 (1) ◽  
pp. 7-16 ◽  
Author(s):  
Changle Ma ◽  
Gaurav Agrawal ◽  
Suresh Subramani
Keyword(s):  
Membrane Protein ◽  
Matrix Protein ◽  
Molecular Mechanisms ◽  
Protein Import ◽  
Protein Translocation ◽  
Peroxisomal Membrane ◽  
Peroxisome Biogenesis Disorders ◽  
Molecular Events ◽  
Protein Biogenesis ◽  
Shed Light

The biogenesis of peroxisomal matrix and membrane proteins is substantially different from the biogenesis of proteins of other subcellular compartments, such as mitochondria and chloroplasts, that are of endosymbiotic origin. Proteins are targeted to the peroxisome matrix through interactions between specific targeting sequences and receptor proteins, followed by protein translocation across the peroxisomal membrane. Recent advances have shed light on the nature of the peroxisomal translocon in matrix protein import and the molecular mechanisms of receptor recycling. Furthermore, the endoplasmic reticulum has been shown to play an important role in peroxisomal membrane protein biogenesis. Defining the molecular events in peroxisome assembly may enhance our understanding of the etiology of human peroxisome biogenesis disorders.

scholarly journals Ectopic Neo-Formed Intracellular Membranes in Escherichia coli: A Response to Membrane Protein-Induced Stress Involving Membrane Curvature and Domains

Biomolecules ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 88 ◽  
Author(s):  
Nadège Jamin ◽  
Manuel Garrigos ◽  
Christine Jaxel ◽  
Annie Frelet-Barrand ◽  
Stéphane Orlowski
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Cytoplasmic Membrane ◽  
Membrane Curvature ◽  
Membrane Domains ◽  
Protein Ratio ◽  
Intracellular Membranes ◽  
High Level

Bacterial cytoplasmic membrane stress induced by the overexpression of membrane proteins at high levels can lead to formation of ectopic intracellular membranes. In this review, we report the various observations of such membranes in Escherichia coli, compare their morphological and biochemical characterizations, and we analyze the underlying molecular processes leading to their formation. Actually, these membranes display either vesicular or tubular structures, are separated or connected to the cytoplasmic membrane, present mono- or polydispersed sizes and shapes, and possess ordered or disordered arrangements. Moreover, their composition differs from that of the cytoplasmic membrane, with high amounts of the overexpressed membrane protein and altered lipid-to-protein ratio and cardiolipin content. These data reveal the importance of membrane domains, based on local specific lipid–protein and protein–protein interactions, with both being crucial for local membrane curvature generation, and they highlight the strong influence of protein structure. Indeed, whether the cylindrically or spherically curvature-active proteins are actively curvogenic or passively curvophilic, the underlying molecular scenarios are different and can be correlated with the morphological features of the neo-formed internal membranes. Delineating these molecular mechanisms is highly desirable for a better understanding of protein–lipid interactions within membrane domains, and for optimization of high-level membrane protein production in E. coli.

scholarly journals Acyl carrier protein promotes MukBEF action in Escherichia coli chromosome organization-segregation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Josh P. Prince ◽  
Jani R. Bolla ◽  
Gemma L. M. Fisher ◽  
Jarno Mäkelä ◽  
Marjorie Fournier ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acyl Carrier Protein ◽  
Coiled Coil ◽  
Acid Synthesis ◽  
Chromosome Organization ◽  
Carrier Protein ◽  
Accessory Proteins ◽  
Structural Maintenance Of Chromosomes ◽  
Smc Proteins

AbstractStructural Maintenance of Chromosomes (SMC) complexes act ubiquitously to compact DNA linearly, thereby facilitating chromosome organization-segregation. SMC proteins have a conserved architecture, with a dimerization hinge and an ATPase head domain separated by a long antiparallel intramolecular coiled-coil. Dimeric SMC proteins interact with essential accessory proteins, kleisins that bridge the two subunits of an SMC dimer, and HAWK/KITE proteins that interact with kleisins. The ATPase activity of the Escherichia coli SMC protein, MukB, which is essential for its in vivo function, requires its interaction with the dimeric kleisin, MukF that in turn interacts with the KITE protein, MukE. Here we demonstrate that, in addition, MukB interacts specifically with Acyl Carrier Protein (AcpP) that has essential functions in fatty acid synthesis. We characterize the AcpP interaction at the joint of the MukB coiled-coil and show that the interaction is necessary for MukB ATPase and for MukBEF function in vivo.

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