Poles Apart: Prokaryotic Polar Organelles and Their Spatial Regulation

Department of Microbiology and Molecular Medicine, Centre Médicale Universitaire, Faculty of Medicine, University of Geneva, Switzerland.
Cold Spring Harbor perspectives in biology (Impact Factor: 8.68). 11/2010; 3(3). DOI: 10.1101/cshperspect.a006809
Source: PubMed


While polar organelles hold the key to understanding the fundamentals of cell polarity and cell biological principles in general, they have served in the past merely for taxonomical purposes. Here, we highlight recent efforts in unraveling the molecular basis of polar organelle positioning in bacterial cells. Specifically, we detail the role of members of the Ras-like GTPase superfamily and coiled-coil-rich scaffolding proteins in modulating bacterial cell polarity and in recruiting effector proteins to polar sites. Such roles are well established for eukaryotic cells, but not for bacterial cells that are generally considered diffusion-limited. Studies on spatial regulation of protein positioning in bacterial cells, though still in their infancy, will undoubtedly experience a surge of interest, as comprehensive localization screens have yielded an extensive list of (polarly) localized proteins, potentially reflecting subcellular sites of functional specialization predicted for organelles.

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Available from: Clare L Kirkpatrick
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    • "The ‘old’ pole is inherited from the mother cell while the ‘new’ pole arises from the FtsZ-generated division septum. Related to this asymmetry, in many bacteria there is preferential localization of certain structures to a single pole, including flagella, pili, and secretion systems [4]. Importantly, the proper assembly and distribution of these polar functionalities are critical for these bacteria to interact with one another and with their environment. "
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    • "Consequently, many proteins exhibit distinct patterns of subcellular localization, some of which arise due to active mechanisms (Shapiro et al. 2009). For example, in rod-shaped bacteria, numerous proteins are localized to a cell pole, where they form complexes critical for processes such as chromosome segregation , motility, and chemotaxis (for review, see Gerdes et al. 2010; Sourjik and Armitage 2010; Kirkpatrick and Viollier 2011). At least in some species, the sets of protein complexes found at the two cell poles (the old and new pole, respectively) differ, generating asymmetry between the two ends of the cell (Shapiro et al. 2009). "
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