Related Experiment Video
Updated: Aug 29, 2025

In Vitro Reconstitution of Self-Organizing Protein Patterns on Supported Lipid Bilayers
Published on: July 28, 2018
A bipartite, low-affinity roadblock domain-containing GAP complex regulates bacterial front-rear polarity
Dobromir Szadkowski1, Luís António Menezes Carreira1, Lotte Søgaard-Andersen1
1Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
Abstract:
The Ras-like GTPase MglA is a key regulator of front-rear polarity in the rod-shaped Myxococcus xanthus cells. MglA-GTP localizes to the leading cell pole and stimulates assembly of the two machineries for type IV pili-dependent motility and gliding motility. MglA-GTP localization is spatially constrained by its cognate GEF, the RomR/RomX complex, and GAP, the MglB Roadblock-domain protein. Paradoxically, RomR/RomX and MglB localize similarly with low and high concentrations at the leading and lagging poles, respectively. Yet, GEF activity dominates at the leading and GAP activity at the lagging pole by unknown mechanisms. Here, we identify RomY and show that it stimulates MglB GAP activity. The MglB/RomY interaction is low affinity, restricting formation of the bipartite MglB/RomY GAP complex almost exclusively to the lagging pole with the high MglB concentration. Our data support a model wherein RomY, by forming a low-affinity complex with MglB, ensures that the high MglB/RomY GAP activity is confined to the lagging pole where it dominates and outcompetes the GEF activity of the RomR/RomX complex. Thereby, MglA-GTP localization is constrained to the leading pole establishing front-rear polarity.
More Related Videos
Related Concept Videos
Cell Polarization by Rho Proteins
Cytoskeletal Proteins in Bacteria
Mechanism of Filopodia Formation
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Mechanism of Lamellipodia Formation
Global Regulatory Systems
Coordination of Gene Expression Processes in Bacteria

