Microbiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 QUICK SEARCH:   [advanced]


     


Microbiology 154 (2008), 3002-3015; DOI  10.1099/mic.0.2008/020677-0
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplementary figure
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via CrossRef
Google Scholar
Right arrow Articles by Ruiz, D.
Right arrow Articles by Contreras, A.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ruiz, D.
Right arrow Articles by Contreras, A.
Agricola
Right arrow Articles by Ruiz, D.
Right arrow Articles by Contreras, A.
Microbiology 154 (2008), 3002-3015; DOI  10.1099/mic.0.2008/020677-0
© 2008 Society for General Microbiology

Phosphorylation-independent activation of the atypical response regulator NblR

Diego Ruiz1, Paloma Salinas1, Maria Luisa Lopez-Redondo2, Maria Luisa Cayuela1, Alberto Marina2 and Asunción Contreras1

1 División de Genética, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain
2 Instituto de Biomedicina de Valencia (CSIC) and CIBERER, 46010 Valencia, Spain

Correspondence
Asunción Contreras
contrera{at}ua.es

Cyanobacteria respond to environmental stress conditions by adjusting their photosynthesis machinery. In Synechococcus sp. PCC 7942, phycobilisome degradation and other acclimation responses after nutrient or high-light stress require activation by the orphan response regulator NblR, a member of the OmpR/PhoB family. Although NblR contains a putative phosphorylatable residue (Asp57), it lacks other conserved residues required to chelate the Mg2+ necessary for aspartic acid phosphorylation or to transduce the phosphorylation signal. In close agreement with these features, NblR was not phosphorylated in vitro by the low-molecular-mass phosphate donor acetyl phosphate and mutation of Asp57 to Ala had no impact on previously characterized NblR functions in Synechococcus. On the other hand, in vitro and in vivo assays show that the default state of NblR is monomeric, suggesting that, despite input differences, NblR activation could involve the same general mechanism of activation by dimerization present in known members of the OmpR/PhoB family. Structural and functional data indicate that the receiver domain of NblR shares similarities with other phosphorylation-independent response regulators such as FrzS and HP1043. To acknowledge the peculiarities of these atypical ‘two-component’ regulators with phosphorylation-independent signal transduction mechanisms, we propose the term PIARR, standing for phosphorylation-independent activation of response regulator.


Abbreviations: BACTH, bacterial adenylate cyclase two-hybrid; HK, histidine kinase; HL, high light; PIARR, phosphorylation-independent activation of response regulator; RD, receiver domain; RR, response regulator; RLU, relative light units

A supplementary figure is available with the online version of this paper.







HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
INT J SYST EVOL MICROBIOL MICROBIOLOGY J GEN VIROL
J MED MICROBIOL ALL SGM JOURNALS
Copyright © 2008 Society for General Microbiology.