Extracellular polysaccharides mediate pilus retraction during social motility of Myxococcus xanthus

被引:190
作者
Li, YN
Sun, H
Ma, XY
Lu, A
Lux, R
Zusman, D
Shi, WY [1 ]
机构
[1] Univ Calif Los Angeles, Inst Mol Biol, Los Angeles, CA 90095 USA
[2] Univ Calif Los Angeles, Sch Dent, Los Angeles, CA 90095 USA
[3] Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA
关键词
gliding motility; type IV pilus; microbial development; biofilm;
D O I
10.1073/pnas.0836639100
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Myxococcus xanthus is a Gram-negative bacterium with a complex life cycle that includes vegetative swarming and fruiting-body formation. Social (S)-motility (coordinated movement of large cell groups) requires both type IV pili and fibrils (extracellular matrix material consisting of polysaccharides and protein). Little is known about the role of this extracellular matrix, or fibril material, in pilus-dependent motility. In this study, mutants lacking fibril material and,therefore, S-motility were found to be hyperpiliated. We demonstrated that addition of fibril material resulted in pilus retraction and rescued this phenotype. The fibril material was further examined to determine the component(s) that were responsible for triggering pilus retraction. Protein-free fibril material was found to be highly active in correcting hyperpiliation. However, the amine sugars present in hydrolyzed fibril material, e.g., glucosamine and N-acetylglucosamine (GlcNAc) had no effect on fibril(-) mutants, but, interestingly, cause hyperpiliation in wildtype cells. In contrast, chitin, a natural GlcNAc polymer, was found to restore pilus retraction in hyperpiliated mutants, indicating that a polysaccharide containing amine sugars is likely required for pilus retraction. These data suggest that the interaction of type IV pili with amine-containing polysaccharides on cell and slime-trail surfaces may trigger pilus retraction, resulting in S-motility and slime-trailing behaviors.
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页码:5443 / 5448
页数:6
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