scholarly journals Evolved sequence features within the intrinsically disordered tail influence FtsZ assembly and bacterial cell division

2018 ◽  
Author(s):  
Megan C. Cohan ◽  
Ammon E. Posey ◽  
Steven J. Grigsby ◽  
Anuradha Mittal ◽  
Alex S. Holehouse ◽  
...  
Keyword(s):  
Cell Division ◽  
Threshold Value ◽  
Ring Formation ◽  
Bacterial Cell Division ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Charged Residues ◽  
Z Ring ◽  
The Impact ◽  
Oppositely Charged

AbstractIntrinsically disordered regions (IDRs) challenge the well-established sequence-structure-function paradigm for describing protein function and evolution. Here, we direct a combination of biophysical and cellular studies to further our understanding of how the intrinsically disordered C-terminal tail of FtsZ contributes to cell division in rod-shaped bacteria. FtsZ is a modular protein that encompasses a conserved GTPase domain and a highly variable intrinsically disordered C-terminal tail (CTT). The CTT is essential for forming the cytokinetic Z-ring. Despite poor sequence conservation of the CTT, the patterning of oppositely charged residues, which refers to the extent of linear mixing / segregation of oppositely charged residues within CTT sequences is bounded within a narrow range. To assess the impact of evolutionary bounds on charge patterning within CTT sequences we performed experiments, aided by sequence design, to quantify the impact of changing the patterning of oppositely charged residues within the CTT on the functions of FtsZ from B. subtilis. Z-ring formation is robust if and only if the extent of linear mixing / segregation of oppositely charged residues within the CTT sequences is within evolutionarily observed bounds. Otherwise, aberrant, CTT-mediated, FtsZ assemblies impair Z-ring formation. The complexities of CTT sequences also have to be above a threshold value because FtsZ variants with low complexity CTTs are not tolerated in cells. Taken together, our results suggest that CTT sequences have evolved to be “just right” and that this is achieved through an optimal extent of charge patterning while maintaining the sequence complexity above a threshold value.

scholarly journals Control of transcriptional activity by design of charge patterning in the intrinsically disordered RAM region of the Notch receptor

2017 ◽  
Vol 114 (44) ◽  
pp. E9243-E9252 ◽  
Author(s):  
Kathryn P. Sherry ◽  
Rahul K. Das ◽  
Rohit V. Pappu ◽  
Doug Barrick
Keyword(s):  
Transcriptional Activation ◽  
Transcriptional Activity ◽  
Notch Pathway ◽  
Notch Receptor ◽  
Sequence Features ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Conformational Properties ◽  
Charged Residues ◽  
Oppositely Charged

Intrinsically disordered regions (IDRs) play important roles in proteins that regulate gene expression. A prominent example is the intracellular domain of the Notch receptor (NICD), which regulates the transcription of Notch-responsive genes. The NICD sequence includes an intrinsically disordered RAM region and a conserved ankyrin (ANK) domain. The 111-residue RAM region mediates bivalent interactions of NICD with the transcription factor CSL. Although the sequence of RAM is poorly conserved, the linear patterning of oppositely charged residues shows minimal variation. The conformational properties of polyampholytic IDRs are governed as much by linear charge patterning as by overall charge content. Here, we used sequence design to assess how changing the charge patterning within RAM affects its conformational properties, the affinity of NICD to CSL, and Notch transcriptional activity. Increased segregation of oppositely charged residues leads to linear decreases in the global dimensions of RAM and decreases the affinity of a construct including a C-terminal ANK domain (RAMANK) for CSL. Increasing charge segregation from WT RAM sharply decreases transcriptional activation for all permutants. Activation also decreases for some, but not all, permutants with low charge segregation, although there is considerable variation. Our results suggest that the RAM linker is more than a passive tether, contributing local and/or long-range sequence features that modulate interactions within NICD and with downstream components of the Notch pathway. We propose that sequence features within IDRs have evolved to ensure an optimal balance of sequence-encoded conformational properties, interaction strengths, and cellular activities.

scholarly journals Basic Residue Clusters in Intrinsically Disordered Regions of Peripheral Membrane Proteins: Modulating 2D Diffusion on Cell Membranes

Physchem ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 152-162
Author(s):  
Miquel Pons
Keyword(s):  
Membrane Proteins ◽  
Electrostatic Interactions ◽  
Lipid Membrane ◽  
Conformational Ensemble ◽  
Basic Residue ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Peripheral Membrane Proteins ◽  
Charged Residues ◽  
Disordered Regions

A large number of peripheral membrane proteins transiently interact with lipids through a combination of weak interactions. Among them, electrostatic interactions of clusters of positively charged amino acid residues with negatively charged lipids play an important role. Clusters of charged residues are often found in intrinsically disordered protein regions, which are highly abundant in the vicinity of the membrane forming what has been called the disordered boundary of the cell. Beyond contributing to the stability of the lipid-bound state, the pattern of charged residues may encode specific interactions or properties that form the basis of cell signaling. The element of this code may include, among others, the recognition, clustering, and selective release of phosphatidyl inositides, lipid-mediated protein-protein interactions changing the residence time of the peripheral membrane proteins or driving their approximation to integral membrane proteins. Boundary effects include reduction of dimensionality, protein reorientation, biassing of the conformational ensemble of disordered regions or enhanced 2D diffusion in the peri-membrane region enabled by the fuzzy character of the electrostatic interactions with an extended lipid membrane.

MinD directly interacting with FtsZ at the H10 helix suggests a model for robust activation of MinC to destabilize FtsZ polymers

2017 ◽  
Vol 474 (18) ◽  
pp. 3189-3205 ◽  
Author(s):  
Ashoka Chary Taviti ◽  
Tushar Kant Beuria
Keyword(s):  
Cell Division ◽  
Single Point ◽  
Point Mutations ◽  
Direct Interaction ◽  
Ring Formation ◽  
Z Ring ◽  
Single Point Mutations ◽  
Biochemical Analyses ◽  
Ftsz Assembly ◽  
The Mind

Cell division in bacteria is a highly controlled and regulated process. FtsZ, a bacterial cytoskeletal protein, forms a ring-like structure known as the Z-ring and recruits more than a dozen other cell division proteins. The Min system oscillates between the poles and inhibits the Z-ring formation at the poles by perturbing FtsZ assembly. This leads to an increase in the FtsZ concentration at the mid-cell and helps in Z-ring positioning. MinC, the effector protein, interferes with Z-ring formation through two different mechanisms mediated by its two domains with the help of MinD. However, the mechanism by which MinD triggers MinC activity is not yet known. We showed that MinD directly interacts with FtsZ with an affinity stronger than the reported MinC–FtsZ interaction. We determined the MinD-binding site of FtsZ using computational, mutational and biochemical analyses. Our study showed that MinD binds to the H10 helix of FtsZ. Single-point mutations at the charged residues in the H10 helix resulted in a decrease in the FtsZ affinity towards MinD. Based on our findings, we propose a novel model for MinCD–FtsZ interaction, where MinD through its direct interaction with FtsZ would trigger MinC activity to inhibit FtsZ functions.

scholarly journals Noc Corrals Migration of FtsZ Protofilaments during Cytokinesis in Bacillus subtilis

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuanchen Yu ◽  
Jinsheng Zhou ◽  
Frederico J. Gueiros-Filho ◽  
Daniel B. Kearns ◽  
Stephen C. Jacobson
Keyword(s):  
Bacillus Subtilis ◽  
Cell Division ◽  
Fluorescence Microscopy ◽  
Control Cell ◽  
Time Lapse ◽  
Ring Formation ◽  
Microfluidic Channels ◽  
Content Type ◽  
The Future ◽  
Z Ring

ABSTRACT Bacteria that divide by binary fission form FtsZ rings at the geometric midpoint of the cell between the bulk of the replicated nucleoids. In Bacillus subtilis, the DNA- and membrane-binding Noc protein is thought to participate in nucleoid occlusion by preventing FtsZ rings from forming over the chromosome. To explore the role of Noc, we used time-lapse fluorescence microscopy to monitor FtsZ and the nucleoid of cells growing in microfluidic channels. Our data show that Noc does not prevent de novo FtsZ ring formation over the chromosome nor does Noc control cell division site selection. Instead, Noc corrals FtsZ at the cytokinetic ring and reduces migration of protofilaments over the chromosome to the future site of cell division. Moreover, we show that FtsZ protofilaments travel due to a local reduction in ZapA association, and the diffuse FtsZ rings observed in the Noc mutant can be suppressed by ZapA overexpression. Thus, Noc sterically hinders FtsZ migration away from the Z-ring during cytokinesis and retains FtsZ at the postdivisional polar site for full disassembly by the Min system. IMPORTANCE In bacteria, a condensed structure of FtsZ (Z-ring) recruits cell division machinery at the midcell, and Z-ring formation is discouraged over the chromosome by a poorly understood phenomenon called nucleoid occlusion. In B. subtilis, nucleoid occlusion has been reported to be mediated, at least in part, by the DNA-membrane bridging protein, Noc. Using time-lapse fluorescence microscopy of cells growing in microchannels, we show that Noc neither protects the chromosome from proximal Z-ring formation nor determines the future site of cell division. Rather, Noc plays a corralling role by preventing protofilaments from leaving a Z-ring undergoing cytokinesis and traveling over the nucleoid.

scholarly journals Sequence-Encoded Charge Patterning of the Intrinsically Disordered Tail of FtsZ Impacts Polymerization and Bacterial Cell Division

2018 ◽  
Vol 114 (3) ◽  
pp. 590a
Author(s):  
Megan Cohan ◽  
Ammon Posey ◽  
Anuradha Mittal ◽  
Steven Grigsby ◽  
Alex Holehouse ◽  
...  
Keyword(s):  
Cell Division ◽  
Bacterial Cell ◽  
Bacterial Cell Division ◽  
Intrinsically Disordered

scholarly journals Lateral interactions between protofilaments of the bacterial tubulin homolog FtsZ are essential for cell division

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Fenghui Guan ◽  
Jiayu Yu ◽  
Jie Yu ◽  
Yang Liu ◽  
Ying Li ◽  
...  
Keyword(s):  
Cell Division ◽  
Bacterial Cell ◽  
Dynamic Structure ◽  
Living Cells ◽  
Lateral Interactions ◽  
Bacterial Cell Division ◽  
Z Ring ◽  
Crystallographic Structures ◽  
Order Structures

The prokaryotic tubulin homolog FtsZ polymerizes into protofilaments, which further assemble into higher-order structures at future division sites to form the Z-ring, a dynamic structure essential for bacterial cell division. The precise nature of interactions between FtsZ protofilaments that organize the Z-ring and their physiological significance remain enigmatic. In this study, we solved two crystallographic structures of a pair of FtsZ protofilaments, and demonstrated that they assemble in an antiparallel manner through the formation of two different inter-protofilament lateral interfaces. Our in vivo photocrosslinking studies confirmed that such lateral interactions occur in living cells, and disruption of the lateral interactions rendered cells unable to divide. The inherently weak lateral interactions enable FtsZ protofilaments to self-organize into a dynamic Z-ring. These results have fundamental implications for our understanding of bacterial cell division and for developing antibiotics that target this key process.

scholarly journals Transcription Regulation of ezrA and Its Effect on Cell Division of Bacillus subtilis

2004 ◽  
Vol 186 (17) ◽  
pp. 5926-5932 ◽  
Author(s):  
Kuei-Min Chung ◽  
Hsin-Hsien Hsu ◽  
Suresh Govindan ◽  
Ban-Yang Chang
Keyword(s):  
Bacillus Subtilis ◽  
Cell Division ◽  
Critical Concentration ◽  
In Vitro Transcription ◽  
Ring Formation ◽  
Negative Regulator ◽  
Cell Length ◽  
Intracellular Level ◽  
Z Ring

ABSTRACT The EzrA protein of Bacillus subtilis is a negative regulator for FtsZ (Z)-ring formation. It is able to modulate the frequency and position of Z-ring formation during cell division. The loss of this protein results in cells with multiple Z rings located at polar as well as medial sites; it also lowers the critical concentration of FtsZ required for ring formation (P. A. Levin, I. G. Kurster, and A. D. Grossman, Proc. Natl. Acad. Sci. USA 96:9642-9647, 1999). We have studied the regulation of ezrA expression during the growth of B. subtilis and its effects on the intracellular level of EzrA as well as the cell length of B. subtilis. With the aid of promoter probing, primer extension, in vitro transcription, and Western blotting analyses, two overlapping σA-type promoters, P1 and P2, located about 100 bp upstream of the initiation codon of ezrA, have been identified. P1, supposed to be an extended −10 promoter, was responsible for most of the ezrA expression during the growth of B. subtilis. Disruption of this promoter reduced the intracellular level of EzrA very significantly compared with disruption of P2. Moreover, deletion of both promoters completely abolished EzrA in B. subtilis. More importantly, the cell length and percentage of filamentous cells of B. subtilis were significantly increased by disruption of the promoter(s). Thus, EzrA is required for efficient cell division during the growth of B. subtilis, despite serving as a negative regulator for Z-ring formation.

scholarly journals MinC, MinD, and MinE Drive Counter-oscillation of Early-Cell-Division Proteins Prior to Escherichia coli Septum Formation

mBio ◽  
2013 ◽  
Vol 4 (6) ◽  
Author(s):  
Paola Bisicchia ◽  
Senthil Arumugam ◽  
Petra Schwille ◽  
David Sherratt
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Lipid Bilayers ◽  
Epifluorescence Microscopy ◽  
Bacterial Cell Division ◽  
Content Type ◽  
Septum Formation ◽  
Early Stages ◽  
Z Ring ◽  
High Concentrations

ABSTRACTBacterial cell division initiates with the formation of a ring-like structure at the cell center composed of the tubulin homolog FtsZ (the Z-ring), which acts as a scaffold for the assembly of the cell division complex, the divisome. Previous studies have suggested that the divisome is initially composed of FtsZ polymers stabilized by membrane anchors FtsA and ZipA, which then recruit the remaining division proteins. The MinCDE proteins prevent the formation of the Z-ring at poles by oscillating from pole to pole, thereby ensuring that the concentration of the Z-ring inhibitor, MinC, is lowest at the cell center. We show that prior to septum formation, the early-division proteins ZipA, ZapA, and ZapB, along with FtsZ, assemble into complexes that counter-oscillate with respect to MinC, and with the same period. We propose that FtsZ molecules distal from high concentrations of MinC form relatively slowly diffusing filaments that are bound by ZapAB and targeted to the inner membrane by ZipA or FtsA. These complexes may facilitate the early stages of divisome assembly at midcell. As MinC oscillates toward these complexes, FtsZ oligomerization and bundling are inhibited, leading to shorter or monomeric FtsZ complexes, which become less visible by epifluorescence microscopy because of their rapid diffusion. Reconstitution of FtsZ-Min waves on lipid bilayers shows that FtsZ bundles partition away from high concentrations of MinC and that ZapA appears to protect FtsZ from MinC by inhibiting FtsZ turnover.IMPORTANCEA big issue in biology for the past 100 years has been that of how a cell finds its middle. InEscherichia coli, over 20 proteins assemble at the cell center at the time of division. We show that the MinCDE proteins, which prevent the formation of septa at the cell pole by inhibiting FtsZ, drive the counter-oscillation of early-cell-division proteins ZapA, ZapB, and ZipA, along with FtsZ. We propose that FtsZ forms filaments at the pole where the MinC concentration is the lowest and acts as a scaffold for binding of ZapA, ZapB, and ZipA: such complexes are disassembled by MinC and reform within the MinC oscillation period before accumulating at the cell center at the time of division. The ability of FtsZ to be targeted to the cell center in the form of oligomers bound by ZipA and ZapAB may facilitate the early stages of divisome assembly.

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