Polaridade celular em organismos procarióticos

quinta-feira, setembro 17, 2009

Cellular Polarity in Prokaryotic Organisms

Jonathan Dworkin

Cold Spring Harb Perspect Biol published 9 September 2009, 10.1101/cshperspect.a003368

Bacteria have a far more complex internal organization than we thought. Polarity proteins may mark "old" and "new" poles, and each gene seems to have a defined spatial location.

Cellular Polarity in Prokaryotic Organisms

Jonathan Dworkin

+ Author Affiliations

Department of Microbiology, College of Physicians and Surgeons, Columbia University, New York, 10032



Simple visual inspection of bacteria indicated that, at least in some otherwise symmetric cells, structures such as flagella were often seen at a single pole. Because these structures are composed of proteins, it was not clear how to reconcile these observations of morphological asymmetry with the widely held view of bacteria as unstructured “bags of enzymes.” However, over the last decade, numerous GFP tagged proteins have been found at specific intracellular locations such as the poles of the cells, indicating that bacteria have a high degree of intracellular organization. Here we will explore the role of chromosomal asymmetry and the presence of “new” and “old” poles that result from the cytokinesis of rod-shaped cells in establishing bipolar and monopolar protein localization patterns. This article is intended to be illustrative, not exhaustive, so we have focused on examples drawn largely from Caulobacter crescentus and Bacillus subtilis, two bacteria that undergo dramatic morphological transformation. We will highlight how breaking monopolar symmetry is essential for the correct development of these organisms.


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