title: The polarity of myxobacterial gliding is regulated by direct interactions between the gliding motors and the Ras homolog MglA.
abstract: Gliding motility in Myxococcus xanthus is powered by flagella stator homologs that move in helical trajectories using proton motive force. The Frz chemosensory pathway regulates the cell polarity axis through MglA, a Ras family GTPase; however, little is known about how MglA establishes the polarity of gliding, because the gliding motors move simultaneously in opposite directions. Here we examined the localization and dynamics of MglA and gliding motors in high spatial and time resolution. We determined that MglA localizes not only at the cell poles, but also along the cell bodies, forming a decreasing concentration gradient toward the lagging cell pole. MglA directly interacts with the motor protein AglR, and the spatial distribution of AglR reversals is positively correlated with the MglA gradient. Thus, the motors moving toward lagging cell poles are less likely to reverse, generating stronger forward propulsion. MglB, the GTPase-activating protein of MglA, regulates motor reversal by maintaining the MglA gradient. Our results suggest a mechanism whereby bacteria use Ras family proteins to modulate cellular polarity.
authors.affiliation: Departments of Molecular and Cell Biology and.
authors.forename: Beiyan
authors.initials: B
authors.lastname: Nan
authors.affiliation: Departments of Molecular and Cell Biology and Physics, University of California, Berkeley, CA 94720.
authors.forename: Jigar N
authors.initials: JN
authors.lastname: Bandaria
authors.affiliation: Departments of Molecular and Cell Biology and.
authors.forename: Kathy Y
authors.initials: KY
authors.lastname: Guo
authors.affiliation: Departments of Molecular and Cell Biology and.
authors.forename: Xue
authors.initials: X
authors.lastname: Fan
authors.affiliation: Departments of Molecular and Cell Biology and.
authors.forename: Amirpasha
authors.initials: A
authors.lastname: Moghtaderi
authors.affiliation: Departments of Molecular and Cell Biology and Physics, University of California, Berkeley, CA 94720.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Yildiz
authors.affiliation: Departments of Molecular and Cell Biology and zusman@berkeley.edu.
authors.forename: David R
authors.initials: DR
authors.lastname: Zusman
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D066146:Cell Body / Q000502:physiology; D016764:Cell Polarity / Q000502:physiology; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000235:genetics / Q000502:physiology*; D009068:Movement / Q000502:physiology; D016941:Myxococcus xanthus / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D018631:ras Proteins / Q000235:genetics / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D020409:Molecular Motor Proteins; D011993:Recombinant Fusion Proteins; C071728:MglA protein, Myxococcus xanthus; D018631:ras Proteins
keywords: cell polarity; gliding motility; protein dynamics; single molecule; sptPALM