ParB Partition Proteins: Complex Formation and Spreading at Bacterial and Plasmid Centromeres

Funnell, Barbara E.

doi:10.3389/fmolb.2016.00044

Cited by 85 publications

(93 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…ParB is a DNA-binding protein and its interactions with parS sequences, which are usually located near oriC, lead to formation of a nucleoprotein complex called the segrosome. Spreading of ParB on adjacent DNA and intermolecular interactions facilitate formation of a complex that organises the newly replicated oriC regions (Chaudhuri and Dean, 2011;Wang et al, 2013;Graham et al, 2014;Broedersz et al, 2014;Chen et al, 2015;Sanchez et al, 2015;Funnell, 2016). ParA proteins are Walker A ATPases that dimerise in an ATP-dependent fashion and interact non-specifically with DNA (Leonard et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

The studies of ParA and ParB dynamics reveal asymmetry of chromosome segregation in mycobacteria

Ginda

Santi

Bousbaine

et al. 2017

Molecular Microbiology

View full text Add to dashboard Cite

Active segregation of bacterial chromosomes usually involves the action of ParB proteins, which bind in proximity of chromosomal origin (oriC) regions forming nucleoprotein complexes - segrosomes. Newly duplicated segrosomes are moved either uni- or bidirectionally by the action of ATPases - ParA proteins. In Mycobacterium smegmatis the oriC region is located in an off-centred position and newly replicated segrosomes are segregated towards cell poles. The elimination of M. smegmatis ParA and/or ParB leads to chromosome segregation defects. Here, we took advantage of microfluidic time-lapse fluorescent microscopy to address the question of ParA and ParB dynamics in M. smegmatis and M. tuberculosis cells. Our results reveal that ParB complexes are segregated in an asymmetrical manner. The rapid movement of segrosomes is dependent on ParA that is transiently associated with the new pole. Remarkably in M. tuberculosis, the movement of the ParB complex is much slower than in M. smegmatis, but segregation as in M. smegmatis lasts approximately 10% of the cell cycle, which suggests a correlation between segregation dynamics and the growth rate. On the basis of our results, we propose a model for the asymmetric action of segregation machinery that reflects unequal division and growth of mycobacterial cells.

show abstract

Section: Introductionmentioning

confidence: 99%

The studies of ParA and ParB dynamics reveal asymmetry of chromosome segregation in mycobacteria

Ginda

Santi

Bousbaine

et al. 2017

Molecular Microbiology

View full text Add to dashboard Cite

show abstract

“…The ParB proteins not only bind the centromere sites on the replicated DNA but also function to trigger movement of ParA along the nucleoid substratum. Multiple ParB proteins bind cooperatively to centromere sites on the cargo DNA to form large partition complexes (Rodionov et al 1999;Schumacher and Funnell 2005;Schumacher 2012;Graham et al 2014;Chen et al 2015;Funnell 2016). Data indicate that disordered typically N-terminal regions of ParB proteins displayed on the partition complexes bind their partner ParA proteins to mediate partition dynamics by stimulating ParA-ATP hydrolysis (Barillà et al 2007;Vecchiarelli et al 2013a;Schumacher et al 2015;Volante and Alonso 2015).…”

mentioning

confidence: 99%

Structures of partition protein ParA with nonspecific DNA and ParB effector reveal molecular insights into principles governing Walker-box DNA segregation

Zhang

Schumacher

2017

Genes Dev.

View full text Add to dashboard Cite

Walker-box partition systems are ubiquitous in nature and mediate the segregation of bacterial and archaeal DNA. Well-studied plasmid Walker-box partition modules require ParA, centromere-DNA, and a centromere-binding protein, ParB. In these systems, ParA-ATP binds nucleoid DNA and uses it as a substratum to deliver ParB-attached cargo DNA, and ParB drives ParA dynamics, allowing ParA progression along the nucleoid. How ParA-ATP binds nonspecific DNA and is regulated by ParB is unclear. Also under debate is whether ParA polymerizes on DNA to mediate segregation. Here we describe structures of key ParA segregation complexes. The ParA-β,γ-imidoadenosine 5 ′ -triphosphate (AMPPNP)-DNA structure revealed no polymers. Instead, ParA-AMPPNP dimerization creates a multifaceted DNA-binding surface, allowing it to preferentially bind high-density DNA regions (HDRs). DNAbound ParA-AMPPNP adopts a dimer conformation distinct from the ATP sandwich dimer, optimized for DNA association. Our ParA-AMPPNP-ParB structure reveals that ParB binds at the ParA dimer interface, stabilizing the ATPase-competent ATP sandwich dimer, ultimately driving ParA DNA dissociation. Thus, the data indicate how harnessing a conformationally adaptive dimer can drive large-scale cargo movement without the requirement for polymers and suggest a segregation mechanism by which ParA-ATP dimers equilibrate to HDRs shown to be localized near cell poles of dividing chromosomes, thus mediating equipartition of attached ParB-DNA substrates.

show abstract

“…The ParB protein recognizes parS sites on the plasmid and recruits the ParA ATPase. ParB is known to form dimers organized into foci (1 per plasmid origin of replication) containing ~200 ParB monomers (27,28). These foci are thought to correspond to liquid-liquid phase separated droplets (14).…”

Section: Pressure Effects On the Bacterial Partition Machinerymentioning

confidence: 99%

Quantitative high-resolution imaging of live microbial cells at high hydrostatic pressure

Bourges

Lazarev

Declerck

et al. 2019

Preprint

View full text Add to dashboard Cite

ABSTRACTThe majority of the Earth’s microbial biomass exists in the Deep Biosphere, in the deep ocean and within the Earth’s crust. While other physical parameters in these environments, such as temperature or pH, can differ substantially, they are all under high-pressures. Beyond emerging genomic information, little is known about the molecular mechanisms underlying the ability of these organisms to survive and grow at pressures that can reach over 1000-fold pressure on the Earth’s surface. The mechanisms of pressure adaptation are also important to in food safety, with the increasing use of high-pressure food processing. Advanced imaging represents an important tool for exploring microbial adaptation and response to environmental changes. Here we describe implementation of a high-pressure sample chamber with a 2-photon scanning microscope system allowing for the first time, quantitative high-resolution two-photon imaging at 100 MPa of living microbes from all three kingdoms of life. We adapted this setup for Fluorescence Lifetime Imaging Microscopy with Phasor analysis (FLIM/Phasor) and investigated metabolic responses to pressure of live cells from mesophilic yeast and bacterial strains, as well as the piezophilic archaeon, Archaeoglobus fulgidus. We also monitored by fluorescence intensity fluctuation-based methods (scanning Number and Brightness (sN&B) and Raster scanning Imaging Correlation Spectroscopy (RICS)) the effect of pressure on the chromosome-associated protein HU and on the ParB partition protein in E. coli, revealing partially reversible dissociation of ParB foci and concomitant nucleoid condensation.SIGNIFICANCEThe majority of the Earth’s microbial biomass exists in high-pressure environments where pressures can reach over 100 MPa. The molecular mechanisms that allow microbes to flourish under such extreme conditions remain to be discovered. The high pressure, high resolution imaging system presented here revealed pressure dependent changes in metabolism and protein interactions in live microbial cells, demonstrating great promise for understanding deep life.

show abstract

ParB Partition Proteins: Complex Formation and Spreading at Bacterial and Plasmid Centromeres

Cited by 85 publications

References 38 publications

The studies of ParA and ParB dynamics reveal asymmetry of chromosome segregation in mycobacteria

The studies of ParA and ParB dynamics reveal asymmetry of chromosome segregation in mycobacteria

Structures of partition protein ParA with nonspecific DNA and ParB effector reveal molecular insights into principles governing Walker-box DNA segregation

Quantitative high-resolution imaging of live microbial cells at high hydrostatic pressure

Contact Info

Product

Resources

About