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A multi‐protein complex from Myxococcus xanthus required for bacterial gliding motility
Author(s) -
Nan Beiyan,
Mauriello Emilia M. F.,
Sun ImHong,
Wong Anita,
Zusman David R.
Publication year - 2010
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2010.07184.x
Subject(s) - myxococcus xanthus , motility , gliding motility , biology , periplasmic space , mcherry , microbiology and biotechnology , cytoplasm , pilus , biochemistry , gene , mutant , escherichia coli , green fluorescent protein , virulence
Summary Myxococcus xanthus moves by gliding motility powered by Type IV pili (S‐motility) and a second motility system, A‐motility, whose mechanism remains elusive despite the identification of ∼40 A‐motility genes. In this study, we used biochemistry and cell biology analyses to identify multi‐protein complexes associated with A‐motility. Previously, we showed that the N‐terminal domain of FrzCD, the receptor for the frizzy chemosensory pathway, interacts with two A‐motility proteins, AglZ and AgmU. Here we characterized AgmU, a protein that localized to both the periplasm and cytoplasm. On firm surfaces, AgmU‐mCherry colocalized with AglZ as distributed clusters that remained fixed with respect to the substratum as cells moved forward. Cluster formation was favoured by hard surfaces where A‐motility is favoured. In contrast, AgmU‐mCherry clusters were not observed on soft agar surfaces or when cells were in large groups, conditions that favour S‐motility. Using glutathione‐S‐transferase affinity chromatography, AgmU was found to interact either directly or indirectly with multiple A‐motility proteins including AglZ, AglT, AgmK, AgmX, AglW and CglB. These proteins, important for the correct localization of AgmU and AglZ, appear to be organized as a motility complex, spanning the cytoplasm, inner membrane and the periplasm. Identification of this complex may be important for uncovering the mechanism of A‐motility.