Scholarlink

<p>In <i>Myxococcus xanthus</i>, a predatory soil bacterium, cell polarity and motility are regulated by MglA (a small GTPase) and its regulators, MglB (a potential GAP) and RomRX (a previously proposed GEF), but their precise roles remain unclear. Using fluorescent nucleotides suitable for fluorescence anisotropy measurements, we show that RomRX does not function as a GEF but instead acts as an effector binding MglA<sub>GTP</sub>. We further find, using an enzymatic model, that MglB exhibits both GAP and GEF properties depending on the local MglA<sub>GDP</sub> concentration. Additionally, RomRX, specifically RomR, effectively dissociates the MglA-MglB complex by sequestering MglB. This low-affinity interaction permits GAP activity while still partitioning the proteins in vivo, as shown by a biomimetic oil-emulsion droplet assay in a cell-sized system. A minimal mathematical model incorporating these interactions and previous findings recapitulates how dynamic interactions between these three players form an invertible polarity axis in the <i>M. xanthus</i> cell.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Cell polarity control by an unconventional G-protein complex in bacteria

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年6月15日

查看全文
  • Céline Dinet,
  • Corinne Sebban-Kreuzer,
  • Deborah Byrne-Kodjabachian,
  • Sébastien Lhospice,
  • Julien Herrou,
  • Fabien Durbesson,
  • Renaud Vincentelli,
  • Vincent Calvez,
  • James Sturgis,
  • Alphée Michelot,
  • Tâm Mignot

摘要

In Myxococcus xanthus, a predatory soil bacterium, cell polarity and motility are regulated by MglA (a small GTPase) and its regulators, MglB (a potential GAP) and RomRX (a previously proposed GEF), but their precise roles remain unclear. Using fluorescent nucleotides suitable for fluorescence anisotropy measurements, we show that RomRX does not function as a GEF but instead acts as an effector binding MglAGTP. We further find, using an enzymatic model, that MglB exhibits both GAP and GEF properties depending on the local MglAGDP concentration. Additionally, RomRX, specifically RomR, effectively dissociates the MglA-MglB complex by sequestering MglB. This low-affinity interaction permits GAP activity while still partitioning the proteins in vivo, as shown by a biomimetic oil-emulsion droplet assay in a cell-sized system. A minimal mathematical model incorporating these interactions and previous findings recapitulates how dynamic interactions between these three players form an invertible polarity axis in the M. xanthus cell.