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Characterization of the rdar morphotype, a multicellular behaviour in Enterobacteriaceae
1Microbiology and Tumor Biology Center, Karolinska Institutet, Box 280, 17177 Stockholm, Sweden. ute.romling@mtc.ki.se
Cellular and Molecular Life Sciences : CMLS
|April 9, 2005
Summary
The bacterial rdAR morphotype involves cellulose and curli fimbriae production, regulated by CsgD. This response regulator controls cyclic-di-GMP (c-di-GMP), a secondary messenger impacting bacterial multicellularity and motility.
Area of Science:
- Microbiology
- Bacterial Physiology
- Molecular Biology
Background:
- The rdAR morphotype in Salmonella enterica and Escherichia coli is defined by cellulose and curli fimbriae expression.
- CsgD is a response regulator that activates cellulose and curli biosynthesis, inducing a multicellular state.
- CsgD's role in cellulose biosynthesis is primarily through activating AdrA, which produces cyclic-di-GMP (c-di-GMP).
Purpose of the Study:
- To investigate the regulatory network controlling c-di-GMP levels in Salmonella Typhimurium.
- To understand the global role of c-di-GMP as a secondary messenger in prokaryotes.
Main Methods:
- Analysis of the regulatory network involving 19 GGDEF/EAL domain proteins in S. Typhimurium.
- Database searches and functional characterization of GGDEF and EAL domain proteins.
Main Results:
- A network of 19 GGDEF/EAL domain proteins tightly regulates c-di-GMP concentration in S. Typhimurium.
- c-di-GMP controls the expression of cellulose and curli, and represses motility.
- Evidence suggests a global role for c-di-GMP in regulating diverse cellular functions across prokaryotes.
Conclusions:
- c-di-GMP is a crucial secondary messenger in bacterial physiology.
- The c-di-GMP regulatory network influences bacterial multicellular behavior, adhesion, and motility.
- c-di-GMP signaling is conserved in prokaryotes, responding to environmental stimuli.