MinE

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The MinE protein is one of three proteins of the Min system encoded by the minB operon required to generate pole to pole oscillations prior to bacterial cell division as a means of specifying the midzone of the cell, as seen in E.coli.

Contents

History

MinE was initially thought to assemble as a static ring at the cell center, thereby preventing the MinCD inhibition complex from localizing and binding there and instead influencing the complex to occupy each bacterial pole. [1] Raskin and de Boer later revealed a dynamic interaction of the Min proteins, where the unstable interaction between the proteins resulted in pole to pole oscillations, resulting in lower concentrations of MinCD complex at the cell center.

Function

MinE is a topological specificity factor that counters the activity of MinCD division inhibitor at the mid-cell division site. MinE functions as a dimer and will bind to membrane-bound MinCD complex, altering its binding dynamics. MinE has membrane binding activity [2] and can also interact with MinD only when on the membrane, suggesting a conformational change in MinD upon interacting with phospholipids that makes it vulnerable to MinE activity. [3] MinE both positively and negatively regulates MinD interaction with membrane. [3]

Deletion analysis has revealed that there exist two domains of interest in MinE, each with separate function. [4] The N-Terminal domain contains the anti-MinCD domain that is necessary and sufficient [1] to interact with MinD and counteract the MinCD-mediated division inhibition and to stimulate the ATPase activity of MinD, resulting in MinD’s detachment from the membrane after ATP hydrolysis. [5] [6] MinE is also known to form a ring near each pole. The purpose of this ring structure is to catalyze the release of membrane-bound MinD in turn, imparting regional specificity of Min protein localization. [7]

Structure

Nuclear Magnetic Resonance (NMR) spectroscopy of truncated MinE revealed a long alpha-helix as well as two anti-parallel beta-strands. These structures are hypothesized to mediate the homodimerization by interaction of alpha/beta structures. These structural studies also support the theory that the MinE ring structure may actually form a multimeric filamentous structure as a function of the interaction of these alpha and beta units. It has also been hypothesized that MinE may potentially form higher order structures, and may not simply be limited to ring formation. [8]

Additional structural study and molecular imaging is needed to elucidate the higher order polymerization structures of MinE and to determine their dynamics on the remaining Min system. Recently, computational models have been applied to explore the limits of this system. [9]

Related Research Articles

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The Min System is a mechanism composed of three proteins MinC, MinD, and MinE used by E. coli as a means of properly localizing the septum prior to cell division. Each component participates in generating a dynamic oscillation of FtsZ protein inhibition between the two bacterial poles to precisely specify the mid-zone of the cell, allowing the cell to accurately divide in two. This system is known to function in conjunction with a second negative regulatory system, the nucleoid occlusion system (NO), to ensure proper spatial and temporal regulation of chromosomal segregation and division.

The MinC protein is one of three proteins in the Min system encoded by the minB operon and which is required to generate pole to pole oscillations prior to bacterial cell division as a means of specifying the midzone of the cell. This function is achieved by preventing the formation of the divisome Z-ring around the poles.

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References

  1. 1 2 Raskin DM; de Boer PA. (1997). "The MinE ring: an FtsZ-independent cell structure required for selection of the correct division site in E. coli". Cell. 91 (5): 685–94. doi: 10.1016/S0092-8674(00)80455-9 . PMID   9393861.
  2. ↑ Hsieh, Cheng-Wei; Lin, Ti-Yu; Lai, Hsin-Mei; Lin, Chu-Chi; Hsieh, Ting-Sung; Shih, Yu-Ling (2010-01-01). "Direct MinE-membrane interaction contributes to the proper localization of MinDE in E. coli". Molecular Microbiology. 75 (2): 499–512. doi:10.1111/j.1365-2958.2009.07006.x. ISSN   1365-2958. PMC   2814086 . PMID   20025670.
  3. 1 2 Vecchiarelli, Anthony G.; Li, Min; Mizuuchi, Michiyo; Hwang, Ling Chin; Seol, Yeonee; Neuman, Keir C.; Mizuuchi, Kiyoshi (2016-03-15). "Membrane-bound MinDE complex acts as a toggle switch that drives Min oscillation coupled to cytoplasmic depletion of MinD". Proceedings of the National Academy of Sciences of the United States of America. 113 (11): E1479–1488. Bibcode:2016PNAS..113E1479V. doi: 10.1073/pnas.1600644113 . ISSN   1091-6490. PMC   4801307 . PMID   26884160.
  4. ↑ Pichoff S; Vollrath B; Touriol C; Bouché JP. (1995). "Deletion analysis of gene minE which encodes the topological specificity factor of cell division in Escherichia coli". Mol. Microbiol. 18 (2): 321–9. doi:10.1111/j.1365-2958.1995.mmi_18020321.x. PMID   8709851. S2CID   24383443.
  5. ↑ Lu-Yan Ma; Glenn King & Lawrence Rothfield (2003). "Mapping the MinE Site Involved in Interaction with the MinD Division Site Selection Protein of Escherichia coli" (PDF). J. Bacteriol. 185 (16): 4948–55. doi:10.1128/JB.185.16.4948-4955.2003. PMC   166455 . PMID   12897015.
  6. ↑ Ma L; King GF; Rothfield L. (2003). "Positioning of the MinE binding site on the MinD surface suggests a plausible mechanism for activation of the Escherichia coli MinD ATPase during division site selection". Mol. Microbiol. 54 (1): 99–108. doi: 10.1111/j.1365-2958.2004.04265.x . PMID   15458408.
  7. ↑ Zonglin Hu; Cristian Saez & Joe Lutkenhaus (2003). "Recruitment of MinC, an Inhibitor of Z-Ring Formation, to the Membrane in Escherichia coli: Role of MinD and MinE". J. Bacteriol. 185 (1): 196–203. doi:10.1128/JB.185.1.196-203.2003. PMC   141945 . PMID   12486056.
  8. ↑ Kang GB; Song HE; Kim MK; Youn HS; Lee JG; An JY; Chun JS; Jeon H; Eom SH. (2010). "Crystal structure of Helicobacter pylori MinE, a cell division topological specificity factor". Mol. Microbiol. 76 (5): 1222–31. doi:10.1111/j.1365-2958.2010.07160.x. PMC   2883074 . PMID   20398219.
  9. ↑ Mike Bonny; Elisabeth Fischer-Friedrich; Martin Loose; Petra Schwille; Karsten Kruse (2013). "Membrane Binding of MinE Allows for a Comprehensive Description of Min-Protein Pattern Formation". PLOS Comput Biol. 9 (12): e1003347. Bibcode:2013PLSCB...9E3347B. doi: 10.1371/journal.pcbi.1003347 . PMC   3854456 . PMID   24339757.
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