A proteomic study of
            <i>Methylobacterium extorquens</i>
            reveals a response regulator essential for epiphytic growth

Gourion, Benjamin; Rossignol, Michel; Vorholt, Julia A.

doi:10.1073/pnas.0603530103

Cited by 151 publications

(143 citation statements)

References 49 publications

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“…Because PhyR uses a degenerate N-terminal sigma factor-like output domain to compete with σ EcfG for NepR binding, this partner switch was coined "sigma factor mimicry" (1). The importance of the alphaproteobacterial GSR in natural environments is underlined by several studies demonstrating its requirement for survival and competitiveness in the phyllosphere in Sphingomonas melonis (10) and Methylobacterium extorquens (8), the establishment of symbiotic interactions in Bradyrhizobium japonicum (9), and host-pathogen interactions in Brucella (6,11) and Bartonella (3) species.…”

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confidence: 99%

“…In Alphaproteobacteria, the GSR is controlled by an alternative extracytoplasmic function (ECF) sigma factor, usually called σ EcfG (1) or ECF15 sigma factor (2), the activity of which is regulated by a conserved partner-switching mechanism (1,(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). In unstressed conditions, σ EcfG is sequestered by its anti-sigma factor NepR.…”

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confidence: 99%

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Complex two-component signaling regulates the general stress response in Alphaproteobacteria

Kaczmarczyk¹,

Hochstrasser²,

Vorholt³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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117

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Significance Bacteria possess many regulatory systems to monitor their environment and adapt their physiology accordingly. Whereas most systems sense one specific signal, the general stress response (GSR) is activated by many signals and protects cells against a wide range of adverse conditions. In Alphaproteobacteria, the GSR is controlled by the response regulator PhyR, but little is known about the upstream pathways. Here, we establish the GSR as a complex regulatory network composed of a particular family of partially redundant sensor kinases and of additional response regulators that modulate PhyR activity in Sphingomonas melonis . Given the broad conservation of this kinase family, it is possible that it plays a general role in the GSR in Alphaproteobacteria.

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confidence: 99%

mentioning

confidence: 99%

Complex two-component signaling regulates the general stress response in Alphaproteobacteria

Kaczmarczyk¹,

Hochstrasser²,

Vorholt³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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117

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“…We recently discovered an original anti-sigma factor antagonist, PhyR, involved in a partner-switching mechanism governing the general stress response in Alphaproteobacteria (12)(13)(14). PhyR is a member of the response regulator family and is unique in that its output domain shows homology to ECF sigma factors (14,15).…”

mentioning

confidence: 99%

“…PhyR is a member of the response regulator family and is unique in that its output domain shows homology to ECF sigma factors (14,15). While the PhyR receiver domain (PhyR REC ) has a classic receiver fold with the conserved phosphorylation site and catalytical motifs, the sigma factor-like output domain (PhyR SL ) essentially retains an ECF sigma factor fold but lacks the σ 2.4 region and is degenerate in the σ 4.2 region, which are normally involved in promoter binding in bona fide ECF sigma factors (12,16).…”

mentioning

confidence: 99%

Structural basis for sigma factor mimicry in the general stress response of Alphaproteobacteria

Campagne

Damberger

Kaczmarczyk³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Reprogramming gene expression is an essential component of adaptation to changing environmental conditions. In bacteria, a widespread mechanism involves alternative sigma factors that redirect transcription toward specific regulons. The activity of sigma factors is often regulated through sequestration by cognate anti-sigma factors; however, for most systems, it is not known how the activity of the anti-sigma factor is controlled to release the sigma factor. Recently, the general stress response sigma factor in Alphaproteobacteria, σ EcfG , was identified. σ EcfG is inactivated by the anti-sigma factor NepR, which is itself regulated by the response regulator PhyR. This key regulator sequesters NepR upon phosphorylation of its PhyR receiver domain via its σ EcfG sigma factor-like output domain (PhyR SL ). To understand the molecular basis of the PhyR-mediated partner-switching mechanism, we solved the structure of the PhyR SL –NepR complex using NMR. The complex reveals an unprecedented anti-sigma factor binding mode: upon PhyR SL binding, NepR forms two helices that extend over the surface of the PhyR SL subdomains. Homology modeling and comparative analysis of NepR, PhyR SL , and σ EcfG mutants indicate that NepR contacts both proteins with the same determinants, showing sigma factor mimicry at the atomic level. A lower density of hydrophobic interactions, together with the absence of specific polar contacts in the σ EcfG –NepR complex model, is consistent with the higher affinity of NepR for PhyR compared with σ EcfG . Finally, by reconstituting the partner switch in vitro, we demonstrate that the difference in affinity of NepR for its partners is sufficient for the switch to occur.

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“…A faixa de pH utilizada para a separação das proteínas foi de 4-7, escolhida com base em outros estudos de expressão de proteínas com M. extorquens (LAUKEL et al, 2004;GOURION et al, 2006). A estreita faixa de pH utilizada também reduziu problemas de co-migração de proteínas para um mesmo ponto, aumentando a resolução dos spots.…”

Section: Separação Das Proteínas Em Géis Bidimensionaisunclassified

Interação entre Methylobacterium extorquens e cana-de-açúcar (Saccharum sp.)

Silva¹

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AGRADECIMENTOSÀ Deus, por me guiar e me dar coragem para superar os momentos difíceis; À meus pais e meus irmãos por todo apoio, amor e compreenção em mais esta etapa da minha vida; Ao Dr. Welington Luiz de Araújo, pela orientação, apoio e amizade nesses dois anos de trabalho; À Profa. Dra. Aline Aparecida Pizzirani-Kleiner e prof. Dr. João Lúcio de Azevedo, pela amizade e receptividade; Ao Prof. Dr. Carlos Alberto Labate, pela disponibilização integral da excelente infra estrutura de seu laboratório, indispensáveis a realização deste trabalho; Ao Departamento de Genética da ESALQ/USP, funcionários e colegas, que foram importantes em algum passo para a realização deste trabalho;Aos coordenadores e professores do curso de pós graduação em Genética e Melhoramento de por RAPD ............................................................................................................31 parcial do 16S rDNA ...................................................................... ...........................................................................................................33 do extrato proteíco.............................................................................. ......................................................................................................................... em gel de poliacrilamida .........................................................................35 de imagem dos géis...................................................................................... extorquens na planta hospedeira .......................................................36 M. extorquens .......................................................................................36 M. extorquens ............................................... As plantas quando colonizadas produzem diversas enzimas de defesa que podem impedir o estabelecimento de microrganismos. Esta condição adversa na planta hospedeira gera uma resposta do microrganismo, a qual está associada à síntese de proteínas e outras moléculas que atuam na sua interação com a planta e alteram a comunidade microbiana associada. Todos os organismos respondem a essa condição, estabelecendo biofilmes, ou sintetizando um grupo de moléculas e proteínas que os protegem de danos e facilita a recuperação. Estas são chamadas proteínas de choque térmico (HSPs), as quais não foram ainda estudadas na interação Methylobacterium -planta. As bactérias do gênero Methylobacterium são metilotróficas facultativas da classe Alfa-proteobactéria, encontradas em relações epifíticas e endofíticas com diferentes espécies vegetais. Assim, o presente trabalho teve como objetivos avaliar o efeito da deficiência da produção de biofilme e de Acil-Homoserina-Lactonas (AHLs), e do estresse térmico de M. extorquens na colonização da planta hospedeira (Saccharum sp.). Para isso, foram usadas linhagens defectivas para produção de biofilme e AHLs, juntamente com a linhagem selvagem submetida ou não ao estresse térmico. Os resultados obtidos mostram a complexidade dos mecanismos envo...

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A proteomic study of Methylobacterium extorquens reveals a response regulator essential for epiphytic growth

Cited by 151 publications

References 49 publications

Complex two-component signaling regulates the general stress response in Alphaproteobacteria

Complex two-component signaling regulates the general stress response in Alphaproteobacteria

Structural basis for sigma factor mimicry in the general stress response of Alphaproteobacteria

Interação entre Methylobacterium extorquens e cana-de-açúcar (Saccharum sp.)

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