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Joe Lutkenhaus - One of the best experts on this subject based on the ideXlab platform.

  • MinC and ftsz mutant analysis provides insight into MinC mind mediated z ring disassembly
    Journal of Biological Chemistry, 2018
    Co-Authors: Kyungtae Park, Alex Dajkovic, Mark Wissel, Shishen Du, Joe Lutkenhaus
    Abstract:

    : The Min system negatively regulates the position of the Z ring, which serves as a scaffold for the divisome that mediates bacterial cytokinesis. In Escherichia coli, this system consists of MinC, which antagonizes assembly of the tubulin homologue FtsZ. MinC is recruited to the membrane by MinD and induced by MinE to oscillate between the cell poles. MinC is a dimer with each monomer consisting of functionally distinct MinCN and MinCC domains, both of which contact FtsZ. According to one model, MinCC/MinD binding to the FtsZ tail positions MinCN at the junction of two GDP-containing subunits in the filament, leading to filament breakage. Others posit that MinC sequesters FtsZ-GDP monomers or that MinCN caps the minus end of FtsZ polymers and that MinCC interferes with lateral interactions between FtsZ filaments. Here, we isolated MinC mutations that impair MinCN function and analyzed FtsZ mutants resistant to MinC/MinD. Surprisingly, we found mutations in both MinC and ftsZ that differentiate inhibition by MinC from inhibition by MinC/MinD. Analysis of these mutations suggests that inhibition of the Z ring by MinC alone is due to sequestration, whereas inhibition by MinC/MinD is not. In conclusion, our genetic and biochemical data support the model that MinC/MinD fragments FtsZ filaments.

  • MinC and FtsZ mutant analysis provides insight into MinC/MinD-mediated Z ring disassembly.
    Journal of Biological Chemistry, 2018
    Co-Authors: Kyungtae Park, Alex Dajkovic, Mark Wissel, Shishen Du, Joe Lutkenhaus
    Abstract:

    : The Min system negatively regulates the position of the Z ring, which serves as a scaffold for the divisome that mediates bacterial cytokinesis. In Escherichia coli, this system consists of MinC, which antagonizes assembly of the tubulin homologue FtsZ. MinC is recruited to the membrane by MinD and induced by MinE to oscillate between the cell poles. MinC is a dimer with each monomer consisting of functionally distinct MinCN and MinCC domains, both of which contact FtsZ. According to one model, MinCC/MinD binding to the FtsZ tail positions MinCN at the junction of two GDP-containing subunits in the filament, leading to filament breakage. Others posit that MinC sequesters FtsZ-GDP monomers or that MinCN caps the minus end of FtsZ polymers and that MinCC interferes with lateral interactions between FtsZ filaments. Here, we isolated MinC mutations that impair MinCN function and analyzed FtsZ mutants resistant to MinC/MinD. Surprisingly, we found mutations in both MinC and ftsZ that differentiate inhibition by MinC from inhibition by MinC/MinD. Analysis of these mutations suggests that inhibition of the Z ring by MinC alone is due to sequestration, whereas inhibition by MinC/MinD is not. In conclusion, our genetic and biochemical data support the model that MinC/MinD fragments FtsZ filaments.

  • MinC mind copolymers are not required for min function
    Molecular Microbiology, 2015
    Co-Authors: Kyungtae Park, Shishen Du, Joe Lutkenhaus
    Abstract:

    : In Escherichia coli, precise placement of the cytokinetic Z ring at midcell requires the concerted action of the three Min proteins. MinD activates MinC, an inhibitor of FtsZ, at least in part, by recruiting it to the membrane and targeting it to the Z ring, while MinE stimulates the MinD ATPase inducing an oscillation that directs MinC/MinD activity away from midcell. Recently, MinC and MinD were shown to form copolymers of alternating dimers of MinC and MinD, and it was suggested that these copolymers are the active form of MinC/MinD. Here, we use MinD mutants defective in binding MinC to generate heterodimers with wild-type MinD that are unable to form MinC/MinD copolymers. Similarly, MinC mutants defective in binding to MinD were used to generate heterodimers with wild-type MinC that are unable to form copolymers. Such heterodimers are active and in the case of MinC were shown to mediate spatial regulation of the Z ring demonstrating that MinC/MinD copolymer formation is not required. Our results are consistent with a model in which a membrane anchored MinC/MinD complex is targeted to the Z ring through the conserved carboxy tail of FtsZ leading to breakage of FtsZ filaments.

  • MinC/MinD copolymers are not required for Min function
    Molecular Microbiology, 2015
    Co-Authors: Kyungtae Park, Shishen Du, Joe Lutkenhaus
    Abstract:

    : In Escherichia coli, precise placement of the cytokinetic Z ring at midcell requires the concerted action of the three Min proteins. MinD activates MinC, an inhibitor of FtsZ, at least in part, by recruiting it to the membrane and targeting it to the Z ring, while MinE stimulates the MinD ATPase inducing an oscillation that directs MinC/MinD activity away from midcell. Recently, MinC and MinD were shown to form copolymers of alternating dimers of MinC and MinD, and it was suggested that these copolymers are the active form of MinC/MinD. Here, we use MinD mutants defective in binding MinC to generate heterodimers with wild-type MinD that are unable to form MinC/MinD copolymers. Similarly, MinC mutants defective in binding to MinD were used to generate heterodimers with wild-type MinC that are unable to form copolymers. Such heterodimers are active and in the case of MinC were shown to mediate spatial regulation of the Z ring demonstrating that MinC/MinD copolymer formation is not required. Our results are consistent with a model in which a membrane anchored MinC/MinD complex is targeted to the Z ring through the conserved carboxy tail of FtsZ leading to breakage of FtsZ filaments.

  • determination of the structure of the mind atp complex reveals the orientation of mind on the membrane and the relative location of the binding sites for mine and MinC
    Molecular Microbiology, 2011
    Co-Authors: Wei Wu, Kyungtae Park, Todd Holyoak, Joe Lutkenhaus
    Abstract:

    Summary The three Min proteins spatially regulate Z ring positioning in Escherichia coli and are dynamically associated with the membrane. MinD binds to vesicles in the presence of ATP and can recruit MinC or MinE. Biochemical and genetic evidence indicate the binding sites for these two proteins on MinD overlap. Here we solved the structure of a hydrolytic-deficient mutant of MinD truncated for the C-terminal amphipathic helix involved in binding to the membrane. The structure solved in the presence of ATP is a dimer and reveals the face of MinD abutting the membrane. Using a combination of random and extensive site-directed mutagenesis additional residues important for MinE and MinC binding were identified. The location of these residues on the MinD structure confirms that the binding sites overlap and reveals that the binding sites are at the dimer interface and exposed to the cytosol. The location of the binding sites at the dimer interface offers a simple explanation for the ATP dependence of MinC and MinE binding to MinD.

Zonglin Hu - One of the best experts on this subject based on the ideXlab platform.

  • analysis of mind mutations reveals residues required for mine stimulation of the mind atpase and residues required for MinC interaction
    Journal of Bacteriology, 2005
    Co-Authors: Huaijin Zhou, Zonglin Hu, Cristian Saez, Ryan J Schulze, Joe Lutkenhaus
    Abstract:

    The MinD ATPase is critical to the oscillation of the Min proteins, which limits formation of the Z ring to midcell. In the presence of ATP, MinD binds to the membrane and recruits MinC, forming a complex that can destabilize the cytokinetic Z ring. MinE, which is also recruited to the membrane by MinD, displaces MinC and stimulates the MinD ATPase, resulting in the oscillation of the Min proteins. In this study we have investigated the role of lysine 11, present in the deviant Walker A motif of MinD, and the three residues in helix 7 (E146, S148, and D152) that interact electrostatically with lysine 11. Lysine 11 is required for interaction of MinD with the membrane, MinC, MinE, and itself. In contrast, the three residues in helix 7 that interact with lysine 11 are not required for binding to the membrane or activation of MinC. They are also not required for MinE binding; however, they are required for MinE to stimulate the MinD ATPase. Interestingly, the D152A mutant self-interacts, binds to the membrane, and recruits MinC and MinE in the presence of ADP as well as ATP. This mutant provides evidence that dimerization of MinD is sufficient for MinD to bind the membrane and recruit its partners.

  • recruitment of MinC an inhibitor of z ring formation to the membrane in escherichia coli role of mind and mine
    Journal of Bacteriology, 2003
    Co-Authors: Zonglin Hu, Cristian Saez, Joe Lutkenhaus
    Abstract:

    In Escherichia coli, the min system prevents division away from midcell through topological regulation of MinC, an inhibitor of Z-ring formation. The topological regulation involves oscillation of MinC between the poles of the cell under the direction of the MinDE oscillator. Since the mechanism of MinC involvement in the oscillation is unknown, we investigated the interaction of MinC with the other Min proteins. We observed that MinD dimerized in the presence of ATP and interacted with MinC. In the presence of a phospholipid bilayer, MinD bound to the bilayer and recruited MinC in an ATP-dependent manner. Addition of MinE to the MinCD-bilayer complex resulted in release of both MinC and MinD. The release of MinC did not require ATP hydrolysis, indicating that MinE could displace MinC from the MinD-bilayer complex. In contrast, MinC was unable to displace MinE bound to the MinD-bilayer complex. These results suggest that MinE induces a conformational change in MinD bound to the bilayer that results in the release of MinC. Also, it is argued that binding of MinD to the membrane activates MinC.

  • a conserved sequence at the c terminus of mind is required for binding to the membrane and targeting MinC to the septum
    Molecular Microbiology, 2003
    Co-Authors: Zonglin Hu, Joe Lutkenhaus
    Abstract:

    MinD is a key component of an oscillatory system that spatially regulates cell division in Escherichia coli. It is a peripheral membrane ATPase that recruits MinC and oscillates between the two halves of the cell in a MinE dependent manner. In vitro MinD binds to phospholipid vesicles in an ATP-dependent manner and is released through MinE-stimulated ATP hydrolysis. In this study we examined the function of the conserved C-terminus of MinD. Short truncations of three and ten amino acids dramatically decreased the ability of MinD to localize to the membrane and spatially regulate division. These truncations bound MinC but were deficient in targeting MinC to the septum. In vitro they dimerized, but were deficient in binding to phospholipid vesicles and undergoing MinE stimulation. We suggest a model in which the ATP-dependent dimerization of MinD affects the conformation of the C-terminal region, a potential amphipathic helix, triggering membrane binding.

  • analysis of MinC reveals two independent domains involved in interaction with mind and ftsz
    Journal of Bacteriology, 2000
    Co-Authors: Zonglin Hu, Joe Lutkenhaus
    Abstract:

    In Escherichia coli FtsZ assembles into a Z ring at midcell while assembly at polar sites is prevented by the min system. MinC, a component of this system, is an inhibitor of FtsZ assembly that is positioned within the cell by interaction with MinDE. In this study we found that MinC consists of two functional domains connected by a short linker. When fused to MalE the N-terminal domain is able to inhibit cell division and prevent FtsZ assembly in vitro. The C-terminal domain interacts with MinD, and expression in wild-type cells as a MalE fusion disrupts min function, resulting in a minicell phenotype. We also find that MinC is an oligomer, probably a dimer. Although the C-terminal domain is clearly sufficient for oligomerization, the N-terminal domain also promotes oligomerization. These results demonstrate that MinC consists of two independently functioning domains: an N-terminal domain capable of inhibiting FtsZ assembly and a C-terminal domain responsible for localization of MinC through interaction with MinD. The fusion of these two independent domains is required to achieve topological regulation of Z ring assembly.

  • the MinC component of the division site selection system in escherichia coli interacts with ftsz to prevent polymerization
    Proceedings of the National Academy of Sciences of the United States of America, 1999
    Co-Authors: Zonglin Hu, Amit Mukherjee, Sebastien Pichoff, Joe Lutkenhaus
    Abstract:

    Abstract Positioning of the Z ring at the midcell site in Escherichia coli is assured by the min system, which masks polar sites through topological regulation of MinC, an inhibitor of division. To study how MinC inhibits division, we have generated a MalE-MinC fusion that retains full biological activity. We find that MalE-MinC interacts with FtsZ and prevents polymerization without inhibiting FtsZ's GTPase activity. MalE-MinC19 has reduced ability to inhibit division, reduced affinity for FtsZ, and reduced ability to inhibit FtsZ polymerization. These results, along with MinC localization, suggest that MinC rapidly oscillates between the poles of the cell to destabilize FtsZ filaments that have formed before they mature into polar Z rings.

Pavel Kabanov - One of the best experts on this subject based on the ideXlab platform.

  • mineral carbon MinC from rock eval analysis as a reliable and cost effective measurement of carbonate contents in shale source and reservoir rocks
    Marine and Petroleum Geology, 2017
    Co-Authors: Chunqing Jiang, Zhuoheng Chen, Denis Lavoie, Jeanne B Percival, Pavel Kabanov
    Abstract:

    Abstract The abundance of carbonate minerals in rocks is an important element for petroleum geochemists, geologists and engineers to consider during hydrocarbon exploration and production. Carbonate minerals can be related to the depositional environments of the source rocks and hence the type of organic matter that can be subsequently modified through diagenetic processes. The total carbonate content in shales can also be used to deduce their fracability as reservoir rock for shale gas/oil extraction. At present, mineralogical analysis by X-ray diffraction (XRD) is the most widely used technique in the oil and gas-related petrophysical and geochemical laboratories for identifying and quantifying carbonate minerals in rock samples. In contrast, the use of the total mineral carbon content parameter MinC (%) from Rock-Eval analysis has been limited despite (1) the parameter's effectiveness as demonstrated through instrument and methodology development; and (2) the presence of a large volume of Rock-Eval results due to its widespread use in the oil and gas industry. In this study, we acquired XRD and Rock-Eval analytical results on over nine hundred rock samples ranging from Ordovician to Cretaceous age from four petroleum sedimentary basins in Canada. Least-squares regression analyses produce empirical equations with R 2 values greater than 0.92 for the correlations between XRD total carbonate contents and the Rock-Eval MinC (%) values of six different suites of samples. This indicates that the MinC (%) values generated by Rock-Eval 6 and other instruments of similar capability can be used with confidence for estimating the amounts of total carbonates in sedimentary rock samples. While the correlation between the two types of carbonate content measurements is geology-specific, a global linear regression model (R 2 of 0.97) based on the large combined data set has been proposed for approximating the total carbonate abundances based on Rock-Eval MinC (%) values.

  • Mineral carbon MinC(%) from Rock-Eval analysis as a reliable and cost-effective measurement of carbonate contents in shale source and reservoir rocks
    Marine and Petroleum Geology, 2017
    Co-Authors: Chunqing Jiang, Zhuoheng Chen, Denis Lavoie, Jeanne B Percival, Pavel Kabanov
    Abstract:

    Abstract The abundance of carbonate minerals in rocks is an important element for petroleum geochemists, geologists and engineers to consider during hydrocarbon exploration and production. Carbonate minerals can be related to the depositional environments of the source rocks and hence the type of organic matter that can be subsequently modified through diagenetic processes. The total carbonate content in shales can also be used to deduce their fracability as reservoir rock for shale gas/oil extraction. At present, mineralogical analysis by X-ray diffraction (XRD) is the most widely used technique in the oil and gas-related petrophysical and geochemical laboratories for identifying and quantifying carbonate minerals in rock samples. In contrast, the use of the total mineral carbon content parameter MinC (%) from Rock-Eval analysis has been limited despite (1) the parameter's effectiveness as demonstrated through instrument and methodology development; and (2) the presence of a large volume of Rock-Eval results due to its widespread use in the oil and gas industry. In this study, we acquired XRD and Rock-Eval analytical results on over nine hundred rock samples ranging from Ordovician to Cretaceous age from four petroleum sedimentary basins in Canada. Least-squares regression analyses produce empirical equations with R 2 values greater than 0.92 for the correlations between XRD total carbonate contents and the Rock-Eval MinC (%) values of six different suites of samples. This indicates that the MinC (%) values generated by Rock-Eval 6 and other instruments of similar capability can be used with confidence for estimating the amounts of total carbonates in sedimentary rock samples. While the correlation between the two types of carbonate content measurements is geology-specific, a global linear regression model (R 2 of 0.97) based on the large combined data set has been proposed for approximating the total carbonate abundances based on Rock-Eval MinC (%) values.

L I Rothfield - One of the best experts on this subject based on the ideXlab platform.

  • stability of the escherichia coli division inhibitor protein MinC requires determinants in the carboxy terminal region of the protein
    Journal of Bacteriology, 1998
    Co-Authors: L I Rothfield
    Abstract:

    Certain mutations in the C-terminal region of the Escherichia coli division inhibitor protein MinC cause loss of function of the division inhibitor by making MinC more sensitive to degradation by Lon protease, implying a possible role for the C-terminal region in regulating the stability and cellular concentration of MinC.

  • roles of MinC and mind in the site specific septation block mediated by the MinCde system of escherichia coli
    Journal of Bacteriology, 1992
    Co-Authors: P A J De Boer, R E Crossley, L I Rothfield
    Abstract:

    The proper placement of the cell division site in Escherichia coli requires the site-specific inactivation of potential division sites at the cell poles in a process that requires the coordinate action of the MinC, MinD, and MinE proteins. In the absence of MinE, the coordinate expression of MinC and MinD leads to a general inhibition of cell division. MinE gives topological specificity to the division inhibition process, so that the septation block is restricted to the cell poles. At normal levels of expression, both MinC and MinD are required for the division block. We show here that, when expressed at high levels, MinC acts as a division inhibitor even in the absence of MinD. The division inhibition that results from MinC overexpression in the absence of MinD is insensitive to the MinE topological specificity factor. The results suggest that MinC is the proximate cause of the septation block and that MinD plays two roles in the MinCDE system--it activates the MinC-dependent division inhibition mechanism and is also required for the sensitivity of the division inhibition system to the MinE topological specificity factor. Images

  • central role for the escherichia coli MinC gene product in two different cell division inhibition systems
    Proceedings of the National Academy of Sciences of the United States of America, 1990
    Co-Authors: P A J De Boer, R E Crossley, L I Rothfield
    Abstract:

    Abstract In Escherichia coli, selection of the proper division site at midcell requires the specific inhibition of septation at two other potential division sites, located at each of the cell poles. This site-specific inhibition of septation is mediated by the gene products of the minicell locus (the minB operon) that includes three genes, MinC, minD, and minE. In this paper we show that one of the components of this division-inhibition system, the MinC gene product, is also an essential component of another division-inhibition system, which is induced by derepression of the dicB gene and leads to inhibition of septation at all potential division sites. The two MinC-dependent division-inhibition systems could be functionally distinguished by their different responses to the minE gene product. The results suggest a model in which a common mechanism, mediated by MinC, is responsible for the division block in a class of division-inhibition systems that can be independently activated by different proteins that determine the specific properties of these systems.

Chunqing Jiang - One of the best experts on this subject based on the ideXlab platform.

  • mineral carbon MinC from rock eval analysis as a reliable and cost effective measurement of carbonate contents in shale source and reservoir rocks
    Marine and Petroleum Geology, 2017
    Co-Authors: Chunqing Jiang, Zhuoheng Chen, Denis Lavoie, Jeanne B Percival, Pavel Kabanov
    Abstract:

    Abstract The abundance of carbonate minerals in rocks is an important element for petroleum geochemists, geologists and engineers to consider during hydrocarbon exploration and production. Carbonate minerals can be related to the depositional environments of the source rocks and hence the type of organic matter that can be subsequently modified through diagenetic processes. The total carbonate content in shales can also be used to deduce their fracability as reservoir rock for shale gas/oil extraction. At present, mineralogical analysis by X-ray diffraction (XRD) is the most widely used technique in the oil and gas-related petrophysical and geochemical laboratories for identifying and quantifying carbonate minerals in rock samples. In contrast, the use of the total mineral carbon content parameter MinC (%) from Rock-Eval analysis has been limited despite (1) the parameter's effectiveness as demonstrated through instrument and methodology development; and (2) the presence of a large volume of Rock-Eval results due to its widespread use in the oil and gas industry. In this study, we acquired XRD and Rock-Eval analytical results on over nine hundred rock samples ranging from Ordovician to Cretaceous age from four petroleum sedimentary basins in Canada. Least-squares regression analyses produce empirical equations with R 2 values greater than 0.92 for the correlations between XRD total carbonate contents and the Rock-Eval MinC (%) values of six different suites of samples. This indicates that the MinC (%) values generated by Rock-Eval 6 and other instruments of similar capability can be used with confidence for estimating the amounts of total carbonates in sedimentary rock samples. While the correlation between the two types of carbonate content measurements is geology-specific, a global linear regression model (R 2 of 0.97) based on the large combined data set has been proposed for approximating the total carbonate abundances based on Rock-Eval MinC (%) values.

  • Mineral carbon MinC(%) from Rock-Eval analysis as a reliable and cost-effective measurement of carbonate contents in shale source and reservoir rocks
    Marine and Petroleum Geology, 2017
    Co-Authors: Chunqing Jiang, Zhuoheng Chen, Denis Lavoie, Jeanne B Percival, Pavel Kabanov
    Abstract:

    Abstract The abundance of carbonate minerals in rocks is an important element for petroleum geochemists, geologists and engineers to consider during hydrocarbon exploration and production. Carbonate minerals can be related to the depositional environments of the source rocks and hence the type of organic matter that can be subsequently modified through diagenetic processes. The total carbonate content in shales can also be used to deduce their fracability as reservoir rock for shale gas/oil extraction. At present, mineralogical analysis by X-ray diffraction (XRD) is the most widely used technique in the oil and gas-related petrophysical and geochemical laboratories for identifying and quantifying carbonate minerals in rock samples. In contrast, the use of the total mineral carbon content parameter MinC (%) from Rock-Eval analysis has been limited despite (1) the parameter's effectiveness as demonstrated through instrument and methodology development; and (2) the presence of a large volume of Rock-Eval results due to its widespread use in the oil and gas industry. In this study, we acquired XRD and Rock-Eval analytical results on over nine hundred rock samples ranging from Ordovician to Cretaceous age from four petroleum sedimentary basins in Canada. Least-squares regression analyses produce empirical equations with R 2 values greater than 0.92 for the correlations between XRD total carbonate contents and the Rock-Eval MinC (%) values of six different suites of samples. This indicates that the MinC (%) values generated by Rock-Eval 6 and other instruments of similar capability can be used with confidence for estimating the amounts of total carbonates in sedimentary rock samples. While the correlation between the two types of carbonate content measurements is geology-specific, a global linear regression model (R 2 of 0.97) based on the large combined data set has been proposed for approximating the total carbonate abundances based on Rock-Eval MinC (%) values.