Scientific
Publications - Work Done by Microbiology Reader Bioscreen C
Archana Varma and Kevin D. Young,
FtsZ Collaborates with Penicillin Binding Proteins To Generate Bacterial
Cell Shape in Escherichia coli,
Journal of Bacteriology, October 2004, p. 6768-6774, Vol. 186, No. 20
ABSTRACT
The mechanisms by which bacteria adopt and maintain individual shapes remain
enigmatic. Outstanding questions include why cells are a certain size, length,
and width; why they are uniform or irregular; and why some branch while others
do not. Previously, we showed that Escherichia coli mutants lacking multiple
penicillin binding proteins (PBPs) display extensive morphological diversity.
Because defective sites in these cells exhibit the structural and functional
characteristics of improperly localized poles, we investigated the connection
between cell division and shape. Here we show that under semipermissive
conditions the temperature-sensitive FtsZ84 protein produces branched and
aberrant cells at a high frequency in mutants lacking PBP 5, and this phenotype
is exacerbated by the loss of additional peptidoglycan endopeptidases.
Surprisingly, certain ftsZ84 strains lyse at the nonpermissive temperature
instead of filamenting, and inhibition of wild-type FtsZ forces some mutants
into tightly wound spirillum-like morphologies. The results demonstrate that
significant aspects of bacterial shape are dictated by a previously unrecognized
relationship between the septation machinery and ostensibly minor peptidoglycan-modifying
enzymes and that under certain circumstances improper FtsZ function can destroy
the structural integrity of the cell.
(Abstract online)
