A landmark protein essential for establishing and perpetuating the polarity of a bacterial cell

Cell. 2006 Mar 10;124(5):1011-23. doi: 10.1016/j.cell.2005.12.040.

Abstract

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Caulobacter crescentus / cytology*
  • Caulobacter crescentus / metabolism
  • Cell Cycle / physiology*
  • Cell Polarity*
  • Flagella / metabolism
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mutation
  • Protein Conformation
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism

Substances

  • Bacterial Proteins
  • Membrane Proteins
  • Recombinant Fusion Proteins