A Landmark Protein Essential for Establishing and Perpetuating the Polarity of a Bacterial Cell

Polarity is often an intrinsic property of the cell, yet little is known about its origin or its maintenance over generations. Here we identify a landmark protein, TipN, which acts as a spatial and temporal cue for setting up the correct polarity in the bacterium Caulobacter crescentus. TipN marks the new pole throughout most of the cell cycle, and its relocation to the nascent poles at the end of division provides a preexisting reference point for orienting the polarity axis in the progeny. Deletion of tipN causes pleiotropic polarity defects, including frequently reversed asymmetry in progeny size and mislocalization of proteins and organelles. Ectopic localization of TipN along the lateral side of the cell creates new axes of polarity leading to cell branching and formation of competent cell poles. Localization defects of the actin-like protein MreB in the DeltatipN mutant suggest that TipN is upstream of MreB in regulating cell polarity.

[1]  L. Shapiro,et al.  Differential localization of two histidine kinases controlling bacterial cell differentiation. , 1999, Molecular cell.

[2]  Kathleen R Ryan,et al.  Fluorescence bleaching reveals asymmetric compartment formation prior to cell division in Caulobacter , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[3]  Roles of the histidine protein kinase pleC in Caulobacter crescentus motility and chemotaxis , 1997, Journal of bacteriology.

[4]  Zemer Gitai,et al.  An actin-like gene can determine cell polarity in bacteria. , 2004, Proceedings of the National Academy of Sciences of the United States of America.

[5]  Lucy Shapiro,et al.  Cell Cycle–Dependent Polar Localization of an Essential Bacterial Histidine Kinase that Controls DNA Replication and Cell Division , 1999, Cell.

[6]  K. Flärdh.  Essential role of DivIVA in polar growth and morphogenesis in Streptomyces coelicolor A3(2) , 2003, Molecular microbiology.

[7]  B. Ely.  Genetics of Caulobacter crescentus. , 1991, Methods in enzymology.

[8]  J. Smit,et al.  Identification of lipopolysaccharide O antigen synthesis genes required for attachment of the S-layer of Caulobacter crescentus. , 2001, Microbiology.

[9]  J. Chant,et al.  Patterns of bud-site selection in the yeast Saccharomyces cerevisiae , 1995, The Journal of cell biology.

[10]  J. Gober,et al.  MreB, the cell shape‐determining bacterial actin homologue, co‐ordinates cell wall morphogenesis in Caulobacter crescentus , 2004, Molecular microbiology.

[11]  Dylan T Burnette,et al.  Cytokinesis Monitoring during Development Rapid Pole-to-Pole Shuttling of a Signaling Protein by Localized Kinase and Phosphatase in Caulobacter , 2004, Cell.

[12]  István Simon,et al.  The HMMTOP transmembrane topology prediction server , 2001, Bioinform..

[13]  N. Agabian,et al.  Envelope-associated nucleoid from Caulobacter crescentus stalked and swarmer cells , 1977, Journal of bacteriology.

[14]  Kathleen R Ryan,et al.  The CtrA response regulator essential for Caulobacter crescentus cell-cycle progression requires a bipartite degradation signal for temporally controlled proteolysis. , 2002, Journal of molecular biology.

[15]  Kathleen R Ryan,et al.  Recruitment of a cytoplasmic response regulator to the cell pole is linked to its cell cycle-regulated proteolysis. , 2004, Proceedings of the National Academy of Sciences of the United States of America.

[16]  D. Drubin,et al.  Origins of Cell Polarity , 1996, Cell.

[17]  Ian T. Paulsen,et al.  Complete genome sequence of Caulobacter crescentus , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[18]  Lucy Shapiro,et al.  Cell Type-Specific Phosphorylation and Proteolysis of a Transcriptional Regulator Controls the G1-to-S Transition in a Bacterial Cell Cycle , 1997, Cell.

[19]  G. Tusnády,et al.  Principles governing amino acid composition of integral membrane proteins: application to topology prediction. , 1998, Journal of molecular biology.

[20]  M. Goldberg,et al.  Presence of Multiple Sites Containing Polar Material in Spherical Escherichia coli Cells That Lack MreB , 2005, Journal of bacteriology.

[21]  Y. Brun,et al.  Caulobacter crescentus Requires RodA and MreB for Stalk Synthesis and Prevention of Ectopic Pole Formation , 2005, Journal of bacteriology.

[22]  Lucy Shapiro,et al.  A dynamically localized histidine kinase controls the asymmetric distribution of polar pili proteins , 2002, The EMBO journal.

[23]  Zemer Gitai,et al.  MreB Actin-Mediated Segregation of a Specific Region of a Bacterial Chromosome , 2005, Cell.

[24]  A. Lupas.  Prediction and analysis of coiled-coil structures. , 1996, Methods in enzymology.

[25]  L. Shapiro,et al.  Identification of a Caulobacter crescentus operon encoding hrcA, involved in negatively regulating heat-inducible transcription, and the chaperone gene grpE , 1996, Journal of bacteriology.

[26]  Yu-Ling Shih,et al.  The MreB and Min cytoskeletal‐like systems play independent roles in prokaryotic polar differentiation , 2005, Molecular microbiology.

[27]  G. Marczynski,et al.  Physiological consequences of blocked Caulobacter crescentus dnaA expression, an essential DNA replication gene , 2001, Molecular microbiology.

[28]  Y. Brun,et al.  A set of ftsZ mutants blocked at different stages of cell division in Caulobacter , 2001, Molecular microbiology.

[29]  A. Newton,et al.  Pattern of unequal cell division and development in Caulobacter crescentus. , 1975, Developmental biology.

[30]  A. Pühler,et al.  A Broad Host Range Mobilization System for In Vivo Genetic Engineering: Transposon Mutagenesis in Gram Negative Bacteria , 1983, Bio/Technology.

[31]  E. Huitema,et al.  Bacterial Birth Scar Proteins Mark Future Flagellum Assembly Site , 2006, Cell.

[32]  N. Ohta,et al.  Signal transduction in the cell cycle regulation of Caulobacter differentiation. , 1996, Trends in microbiology.