The Dif Chemosensory System Is Required for S Motility, Biofilm Formation, Chemotaxis, and Development in Myxococcus xanthus

2014 ◽  
pp. 65-74
Author(s):  
Lawrence J. Shimkets
Keyword(s):  
Biofilm Formation ◽  
Myxococcus Xanthus ◽  
Chemosensory System

The Frz Chemosensory System of Myxococcus xanthus

Myxobacteria ◽  
2014 ◽  
pp. 123-132 ◽  
Author(s):  
David R. Zusman ◽  
Yuki F. Inclán ◽  
Tâm Mignot
Keyword(s):  
Myxococcus Xanthus ◽  
Chemosensory System

scholarly journals CrdS and CrdA Comprise a Two-Component System That Is Cooperatively Regulated by the Che3 Chemosensory System in Myxococcus xanthus

mBio ◽  
2011 ◽  
Vol 2 (4) ◽  
Author(s):  
Jonathan W. Willett ◽  
John R. Kirby
Keyword(s):  
Signal Transduction ◽  
Myxococcus Xanthus ◽  
Complex Signal ◽  
Central Processor ◽  
Two Component System ◽  
Component System ◽  
Chemosensory System ◽  
Content Type ◽  
Phosphorylation State ◽  
Two Component

ABSTRACTMyxococcus xanthusserves as a model organism for development and complex signal transduction. Regulation of developmental aggregation and sporulation is controlled, in part, by the Che3 chemosensory system. The Che3 pathway consists of homologs to two methyl-accepting chemotaxis proteins (MCPs), CheA, CheW, CheB, and CheR but not CheY. Instead, the output for Che3 is the NtrC homolog CrdA, which functions to regulate developmental gene expression. In this paper we have identified an additional kinase, CrdS, which directly regulates the phosphorylation state of CrdA. Both epistasis andin vitrophosphotransfer assays indicate that CrdS functions as part of the Che3 pathway and, in addition to CheA3, serves to regulate CrdA phosphorylation inM. xanthus. We provide kinetic data for CrdS autophosphorylation and demonstrate specificity for phosphotransfer from CrdS to CrdA. We further demonstrate that CheA3 destabilizes phosphorylated CrdA (CrdA~P), indicating that CheA3 likely acts as a phosphatase. Both CrdS and CheA3 control developmental progression by regulating the phosphorylation state of CrdA~P in the cell. These results support a model in which a classical two-component system and a chemosensory system act synergistically to control the activity of the response regulator CrdA.IMPORTANCEWhile phosphorylation-mediated signal transduction is well understood in prototypical chemotaxis and two-component systems (TCS), chemosensory regulation of alternative cellular functions (ACF) has not been clearly defined. The Che3 system inMyxococcus xanthusis a member of the ACF class of chemosensory systems and regulates development via the transcription factor CrdA (chemosensoryregulator ofdevelopment) (K. Wuichet and I. B. Zhulin, Sci. Signal. 3:ra50, 2010; J. R. Kirby and D. R. Zusman, Proc. Natl. Acad. Sci. U. S. A. 100:2008–2013, 2003). We have identified and characterized a homolog of NtrB, designated CrdS, capable of specifically phosphorylating the NtrC homolog CrdA inM. xanthus. Additionally, we demonstrate that the CrdSA two-component system is negatively regulated by CheA3, the central processor within the Che3 system ofM. xanthus. To our knowledge, this study provides the first example of an ACF chemosensory system regulating a prototypical two-component system and extends our understanding of complex regulation of developmental signaling pathways.

scholarly journals Gliding Motility Revisited: How Do the Myxobacteria Move without Flagella?

2010 ◽  
Vol 74 (2) ◽  
pp. 229-249 ◽  
Author(s):  
Emilia M. F. Mauriello ◽  
Tâm Mignot ◽  
Zhaomin Yang ◽  
David R. Zusman
Keyword(s):  
Biofilm Formation ◽  
Protein Localization ◽  
Myxococcus Xanthus ◽  
Gliding Motility ◽  
Solid Surfaces ◽  
Biological Functions ◽  
Fruiting Body Formation ◽  
Body Formation ◽  
Periplasmic Flagella ◽  
Motile Bacterium

SUMMARY In bacteria, motility is important for a wide variety of biological functions such as virulence, fruiting body formation, and biofilm formation. While most bacteria move by using specialized appendages, usually external or periplasmic flagella, some bacteria use other mechanisms for their movements that are less well characterized. These mechanisms do not always exhibit obvious motility structures. Myxococcus xanthus is a motile bacterium that does not produce flagella but glides slowly over solid surfaces. How M. xanthus moves has remained a puzzle that has challenged microbiologists for over 50 years. Fortunately, recent advances in the analysis of motility mutants, bioinformatics, and protein localization have revealed likely mechanisms for the two M. xanthus motility systems. These results are summarized in this review.

scholarly journals Proteins Associated with the Myxococcus xanthus Extracellular Matrix

2007 ◽  
Vol 189 (21) ◽  
pp. 7634-7642 ◽  
Author(s):  
Patrick D. Curtis ◽  
James Atwood ◽  
Ron Orlando ◽  
Lawrence J. Shimkets
Keyword(s):  
Extracellular Matrix ◽  
Biofilm Formation ◽  
Myxococcus Xanthus ◽  
Sodium Dodecyl ◽  
Wild Type ◽  
Fruiting Body Formation ◽  
Ecm Proteins ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
In The Wild

ABSTRACT Fruiting body formation of Myxococcus xanthus, like biofilm formation of many other organisms, involves the production of an extracellular matrix (ECM). While the polysaccharide component has been studied, the protein component has been largely unexplored. Proteins associated with the ECM were solubilized from purified ECM by boiling with sodium dodecyl sulfate and were identified by liquid chromatography-tandem mass spectrometry of tryptic fragments. The ECM is enriched in proteins of novel function; putative functions were assigned for only 5 of the 21 proteins. Thirteen putative ECM proteins had lipoprotein secretion signals. The genes for many ECM proteins were disrupted in the wild-type (WT), fibA, and pilA backgrounds. Disruption of the MXAN4860 gene had no effect in the WT or fibA background but in the pilA background resulted in a 24-h delay in aggregation and sporulation compared to its parent. The results of this study show that the M. xanthus ECM proteome is diverse and novel.

scholarly journals Role of σD in Regulating Genes and Signals during Myxococcus xanthus Development

2006 ◽  
Vol 188 (9) ◽  
pp. 3246-3256 ◽  
Author(s):  
Poorna Viswanathan ◽  
Mitchell Singer ◽  
Lee Kroos
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Biofilm Formation ◽  
Myxococcus Xanthus ◽  
Control Cell ◽  
Wild Type ◽  
Developmental Genes ◽  
Measuring Signal ◽  
Early Developmental

ABSTRACT Starvation-induced development of Myxococcus xanthus is an excellent model for biofilm formation because it involves cell-cell signaling to coordinate formation of multicellular mounds, gene expression, and cellular differentiation into spores. The role of σD, an alternative σ factor important for viability in stationary phase and for stress responses, was investigated during development by measuring signal production, gene expression, and sporulation of a sigD null mutant alone and upon codevelopment with wild-type cells or signaling mutants. The sigD mutant responded to starvation by inducing (p)ppGpp synthesis normally but was impaired for production of A-signal, an early cell density signal, and for production of the morphogenetic C-signal. Induction of early developmental genes was greatly reduced, and expression of those that depend on A-signal was not restored by codevelopment with wild-type cells, indicating that σD is needed for cellular responses to A-signal. Despite these early developmental defects, the sigD mutant responded to C-signal supplied by codeveloping wild-type cells by inducing a subset of late developmental genes. σD RNA polymerase is dispensable for transcription of this subset, but a distinct regulatory class, which includes genes essential for sporulation, requires σD RNA polymerase or a gene under its control, cell autonomously. The level of sigD transcript in a relA mutant during growth is much lower than in wild-type cells, suggesting that (p)ppGpp positively regulates sigD transcription in growing cells. The sigD transcript level drops in wild-type cells after 20 min of starvation and remains low after 40 min but rises in a relA mutant after 40 min, suggesting that (p)ppGpp negatively regulates sigD transcription early in development. We conclude that σD synthesized during growth occupies a position near the top of a regulatory hierarchy governing M. xanthus development, analogous to σ factors that control biofilm formation of other bacteria.

scholarly journals Predation by Myxococcus xanthus Induces Bacillus subtilis To Form Spore-Filled Megastructures

2014 ◽  
Vol 81 (1) ◽  
pp. 203-210 ◽  
Author(s):  
Susanne Müller ◽  
Sarah N. Strack ◽  
Sarah E. Ryan ◽  
Daniel B. Kearns ◽  
John R. Kirby
Keyword(s):  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Myxococcus Xanthus ◽  
Common Mechanism ◽  
Alternative Mechanism ◽  
Dense Matrix ◽  
Interspecies Interactions ◽  
Content Type ◽  
New Type ◽  
Surfactin Production

ABSTRACTBiofilm formation is a common mechanism for surviving environmental stress and can be triggered by both intraspecies and interspecies interactions. Prolonged predator-prey interactions between the soil bacteriumMyxococcus xanthusandBacillus subtiliswere found to induce the formation of a new type ofB. subtilisbiofilm, termed megastructures. Megastructures are tree-like brachiations that are as large as 500 μm in diameter, are raised above the surface between 150 and 200 μm, and are filled with viable endospores embedded within a dense matrix. Megastructure formation did not depend on TasA, EpsE, SinI, RemA, or surfactin production and thus is genetically distinguishable from colony biofilm formation on MSgg medium. AsB. subtilisendospores are not susceptible to predation byM. xanthus, megastructures appear to provide an alternative mechanism for survival. In addition,M. xanthusfruiting bodies were found immediately adjacent to the megastructures in nearly all instances, suggesting thatM. xanthusis unable to acquire sufficient nutrients from cells housed within the megastructures. Lastly, aB. subtilismutant lacking the ability to defend itself via bacillaene production formed megastructures more rapidly than the parent. Together, the results indicate that production of the megastructure facilitatesB. subtilisescape into dormancy via sporulation.

scholarly journals Three PilZ domain proteins, PlpA, PixA and PixB, have distinct functions in regulation of motility and development in Myxococcus xanthus

2021 ◽  
Author(s):  
Sofya Kuzmich ◽  
Dorota Skotnicka ◽  
Dobromir Szadkowski ◽  
Philipp Klos ◽  
María Pérez‐Burgos ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Myxococcus Xanthus ◽  
Type Iv Pili ◽  
Gliding Motility ◽  
Intact Protein ◽  
Dependent Manner ◽  
Chemosensory System ◽  
Type Iv ◽  
Acetyltransferase Domain

In bacteria, the nucleotide-based second messenger bis-(3’-5’)-cyclic dimeric GMP (c-di-GMP) binds to effectors to generate outputs in response to changes in the environment. In Myxococcus xanthus, c-di-GMP regulates type IV pili-dependent motility and the starvation-induced developmental program that results in formation of spore-filled fruiting bodies; however, little is known about the effectors that bind c-di-GMP. Here, we systematically inactivated all 24 genes encoding PilZ domain-containing proteins, which are among the most common c-di-GMP effectors. We confirm that the stand-alone PilZ-domain protein PlpA is important for regulation of motility independently of the Frz chemosensory system, and that Pkn1, which is composed of a Ser/Thr kinase domain and a PilZ domain, is specifically important for development. Moreover, we identify two PilZ-domain proteins that have distinct functions in regulating motility and development. PixB, which is composed of two PilZ domains and an acetyltransferase domain, binds c-di-GMP in vitro and regulates type IV pili-dependent and gliding motility in a Frz-dependent manner as well as development. The acetyltransferase domain is required and sufficient for function during growth while all three domains and c-di-GMP binding are essential for PixB function during development. PixA is a response regulator composed of a PilZ domain and a receiver domain, binds c-di-GMP in vitro, and regulates motility independently of the Frz system likely by setting up the polarity of the two motility systems. Our results support a model whereby PlpA, PixA and PixB act in independent pathways and have distinct functions in regulation of motility. Importance c-di-GMP signaling controls bacterial motility in many bacterial species by binding to downstream effector proteins. Here, we identify two PilZ domain-containing proteins in Myxococcus xanthus that bind c-di-GMP. We show that PixB, which contains two PilZ domains and an acetyltransferase domain, acts in a manner that depends on the Frz chemosensory system to regulate motility via the acetyltransferase domain while the intact protein and c-di-GMP binding are essential for PixB to support development. By contrast, PixA acts acts in Frz-independent mannerto regulate motility. Together with previous observations, we conclude that PilZ-domain proteins and c-di-GMP act in multiple independent pathways to regulate motility and development in M. xanthus.

scholarly journals Three PilZ domain proteins, PlpA, PixA and PixB, have distinct functions in regulation of motility and development in Myxococcus xanthus

2021 ◽  
Author(s):  
Sofya Kuzmich ◽  
Dorota Skotnicka ◽  
Dobromir Szadkowski ◽  
Philipp Klos ◽  
Maria Perez-Burgos ◽  
...  
Keyword(s):  
Response Regulator ◽  
Myxococcus Xanthus ◽  
Type Iv Pili ◽  
Gliding Motility ◽  
Chemosensory System ◽  
Developmental Program ◽  
Type Iv ◽  
Genes Encoding ◽  
Acetyltransferase Domain

In bacteria, the nucleotide-based second messenger bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) binds to effectors to generate outputs in response to changes in the environment. In Myxococcus xanthus, c-di-GMP regulates type IV pili-dependent motility and the starvation-induced developmental program that results in the formation of spore-filled fruiting bodies; however, little is known about the effectors that bind c-di-GMP. Here, we systematically inactivated all 24 genes encoding PilZ domain-containing proteins, which are among the most common c-di-GMP receptors. We confirm that PlpA, a stand-alone PilZ-domain protein, is specifically important for motility and that Pkn1, which is composed of a Ser/Thr domain and a PilZ domain, is specifically important for development. Moreover, we identify two PilZ-domain proteins that have distinct functions in regulating motility and development. PixB, which is composed of two PilZ domains and an acetyltransferase domain, binds c-di-GMP in vitro and regulates type IV pili-dependent and gliding motility upstream of the Frz chemosensory system as well as development. The acetyltransferase domain is required and sufficient for function during growth while all three domains and c-di-GMP binding are essential for PixB function during development. PixA is a response regulator composed of a PilZ domain and a receiver domain, binds c-di-GMP in vitro, and regulates motility downstream of the Frz chemosensory system by setting up the polarity of the two motility systems. Our results support a model whereby the three proteins PlpA, PixA and PixB act in parallel pathways and have distinct functions to regulation of motility.

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