title: Protein-protein interaction domains of Bacillus subtilis DivIVA.
abstract: DivIVA proteins are curvature-sensitive membrane binding proteins that recruit other proteins to the poles and the division septum. They consist of a conserved N-terminal lipid binding domain fused to a less conserved C-terminal domain. DivIVA homologues interact with different proteins involved in cell division, chromosome segregation, genetic competence, or cell wall synthesis. It is unknown how DivIVA interacts with these proteins, and we used the interaction of Bacillus subtilis DivIVA with MinJ and RacA to investigate this. MinJ is a transmembrane protein controlling division site selection, and the DNA-binding protein RacA is crucial for chromosome segregation during sporulation. Initial bacterial two-hybrid experiments revealed that the C terminus of DivIVA appears to be important for recruiting both proteins. However, the interpretation of these results is limited since it appeared that C-terminal truncations also interfere with DivIVA oligomerization. Therefore, a chimera approach was followed, making use of the fact that Listeria monocytogenes DivIVA shows normal polar localization but is not biologically active when expressed in B. subtilis. Complementation experiments with different chimeras of B. subtilis and L. monocytogenes DivIVA suggest that MinJ and RacA bind to separate DivIVA domains. Fluorescence microscopy of green fluorescent protein-tagged RacA and MinJ corroborated this conclusion and suggests that MinJ recruitment operates via the N-terminal lipid binding domain, whereas RacA interacts with the C-terminal domain. We speculate that this difference is related to the cellular compartments in which MinJ and RacA are active: the cell membrane and the cytoplasm, respectively.
authors.affiliation: Robert Koch Institute, FG11-Division of Bacterial Infections, Wernigerode, Germany.
authors.forename: Suey
authors.initials: S
authors.lastname: van Baarle
authors.forename: Ilkay Nazli
authors.initials: IN
authors.lastname: Celik
authors.forename: Karan Gautam
authors.initials: KG
authors.lastname: Kaval
authors.forename: Marc
authors.initials: M
authors.lastname: Bramkamp
authors.forename: Leendert W
authors.initials: LW
authors.lastname: Hamoen
authors.forename: Sven
authors.initials: S
authors.lastname: Halbedel
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism*; D002455:Cell Division; D002473:Cell Wall / Q000378:metabolism; D020090:Chromosome Segregation; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics; D008089:Listeria monocytogenes / Q000737:chemistry / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C104636:DivIVA protein, bacteria; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins