title: The histidine kinase PdhS controls cell cycle progression of the pathogenic alphaproteobacterium Brucella abortus.
abstract: Bacterial differentiation is often associated with the asymmetric localization of regulatory proteins, such as histidine kinases. PdhS is an essential and polarly localized histidine kinase in the pathogenic alphaproteobacterium Brucella abortus. After cell division, PdhS is asymmetrically segregated between the two sibling cells, highlighting a differentiation event. However, the function(s) of PdhS in the B. abortus cell cycle remains unknown. We used an original approach, the pentapeptide scanning mutagenesis method, to generate a thermosensitive allele of pdhS. We report that a B. abortus strain carrying this pdhS allele displays growth arrest and an altered DivK-yellow fluorescent protein (YFP) polar localization at the restrictive temperature. Moreover, the production of a nonphosphorylatable PdhS protein or truncated PdhS proteins leads to dominant-negative effects by generating morphological defects consistent with the inhibition of cell division. In addition, we have used a domain mapping approach combined with yeast two-hybrid and fluorescence microscopy methods to better characterize the unusual PdhS sensory domain. We have identified a fragment of the PdhS sensory domain required for protein-protein interaction (amino acids [aa] 210 to 434), a fragment sufficient for polar localization (aa 1 to 434), and a fragment (aa 527 to 661) whose production in B. abortus correlates with the generation of cell shape alterations. The data support a model in which PdhS acts as an essential regulator of cell cycle progression in B. abortus and contribute to a better understanding of the differentiation program inherited by the two sibling cells.
authors: Microorganisms Biology Research Unit (URBM), University of Namur (FUNDP), Namur, Belgium.
authors: Charles
authors: C
authors: Van der Henst
authors: François
authors: F
authors: Beaufay
authors: Johann
authors: J
authors: Mignolet
authors: Christian
authors: C
authors: Didembourg
authors: Julien
authors: J
authors: Colinet
authors: Bernard
authors: B
authors: Hallet
authors: Jean-Jacques
authors: JJ
authors: Letesson
authors: Xavier
authors: X
authors: De Bolle
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002003:Brucella abortus / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D000071677:Histidine Kinase; D008164:Luminescent Proteins; D016296:Mutagenesis; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D020798:Two-Hybrid System Techniques
chemical_list: D001426:Bacterial Proteins; D008164:Luminescent Proteins; C054562:yellow fluorescent protein, Bacteria; D011494:Protein Kinases; D000071677:Histidine Kinase