POSTERS - BLAST X - University of Utah

BLAST X Mon. Evening Session
DYNAMIC LOCALIZATION OF FrzCD IN MYXOCOCCUS XANTHUS
Emilia M.F. Mauriello 1 , David P. Astling 1 , Oleksii Sliusarenko 2 and David R. Zusman 1
University of California, Department of Molecular and Cell Biology, Berkeley, CA 94720, USA 1 ;
Yale University, Department of Molecular, Cell and Developmental Biology New Haven, CT
06520, USA 2
Directional motility in the gliding bacterium Myxococcus xanthus requires controlled cell
reversals mediated by the Frz chemosensory system. FrzCD, a cytoplasmic chemoreceptor,
does not form membrane bound polar clusters typical for most bacteria, but rather cytoplasmic
clusters that are helically arranged and span the cell length. This unusual localization is
maintained in the absence of the CheA homologs FrzE or CheA4, and the CheW homologs
FrzA or FrzB. In contrast, MCPs lose their respective polar or cytoplasmic localization in
Escherichia coli and Rhodobacter spheroides strains lacking CheA and/or CheW (1, 2). The
distribution of FrzCD in living cells was found to be dynamic: FrzCD was localized in clusters
that continuously changed their size, number, and position. The number of FrzCD clusters was
correlated with cellular reversal frequency: fewer clusters were observed in hypo-reversing
mutants and additional clusters observed in hyper-reversing mutants. When moving cells made
side-to-side contacts, FrzCD clusters in adjacent cells showed transient alignments. These
events were frequently followed by one of the interacting cells reversing. These observations
suggest that FrzCD detects signals from a cell-contact sensitive signaling system and then relocalizes
as it directs reversals to distributed motility engines.
References:
1. Maddock, J.R., and Shapiro, L. (1993) Science 259: 1717-1723.
2. Wadhams, G.H., Martin, A.C., Warren, A.V., and Armitage, J.P. (2005) Mol Microbiol 58(3):
895-902.
3. Bustamante, V.H., Martínez-Flores, I., Vlamakis H.C., and Zusman, D. (2004) Mol Microbiol
58(5): 1501-1513.
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