The polar Ras-like GTPase MglA activates type IV pilus via SgmX to enable twitching motility in
| Autor: | Romain, Mercier, Sarah, Bautista, Maëlle, Delannoy, Margaux, Gibert, Annick, Guiseppi, Julien, Herrou, Emilia M F, Mauriello, Tâm, Mignot |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America |
| ISSN: | 1091-6490 |
| Popis: | Significance The type IV pilus (Tfp) is a multipurpose machine found on bacterial surfaces that works by cycles of synthesis/retraction of a pilin fiber. During surface (twitching) motility, the coordinated actions of multiple Tfps at the cell pole promotes single cells and synchronized group movements. Here, directly observing polar Tfp machines in action during motility of Myxococcus xanthus, we identified the mechanism underlying pole-specific Tfps activation. In this process, the Ras-like protein MglA targets a novel essential Tfp-activator, SgmX, to the pole, ensuring both the unipolar activation of Tfps and its switching to the opposite pole when cells reverse their movement. Thus, a dynamic cascade of polar activators regulates multicellular movements, a feature that is likely conserved in other twitching bacteria. Type IV pili (Tfp) are highly conserved macromolecular structures that fulfill diverse cellular functions, such as adhesion to host cells, the import of extracellular DNA, kin recognition, and cell motility (twitching). Outstandingly, twitching motility enables a poorly understood process by which highly coordinated groups of hundreds of cells move in cooperative manner, providing a basis for multicellular behaviors, such as biofilm formation. In the social bacteria Myxococcus xanthus, we know that twitching motility is under the dependence of the small GTPase MglA, but the underlying molecular mechanisms remain elusive. Here we show that MglA complexed to GTP recruits a newly characterized Tfp regulator, termed SgmX, to activate Tfp machines at the bacterial cell pole. This mechanism also ensures spatial regulation of Tfp, explaining how MglA switching provokes directional reversals. This discovery paves the way to elucidate how polar Tfp machines are regulated to coordinate multicellular movements, a conserved feature in twitching bacteria. |
| Databáze: | OpenAIRE |
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