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Polar localization of a bacterial chemoreceptor
M R Alley1, J R Maddock, L Shapiro
1Department of Developmental Biology, Beckman Center, Stanford University School of Medicine, California 94305-5427.
Genes & Development
|May 1, 1992
Summary
Bacterial chemotaxis proteins (MCPs) localize to specific cell poles. Specific protein regions interact with cell sites, directing subcellular localization in prokaryotes.
Area of Science:
- Microbiology
- Cell Biology
- Molecular Biology
Background:
- Bacterial chemotaxis is crucial for microbial motility and survival.
- Signal transducer proteins, like methyl-accepting chemotaxis proteins (MCPs), are integral membrane receptors.
- In Caulobacter crescentus, MCPs are localized to the flagellum-bearing pole of swarmer cells.
Purpose of the Study:
- To investigate the molecular determinants of subcellular localization for bacterial chemotaxis signal transducer proteins.
- To determine if conserved domains in MCPs mediate polar localization across different bacterial species.
Main Methods:
- Expression of Escherichia coli MCP in Caulobacter crescentus.
- Analysis of protein localization using microscopy.
- Sequence comparison of MCP carboxy-terminal domains between C. crescentus and E. coli.
Main Results:
- Amino-terminal sequences of MCPs direct membrane targeting.
- Carboxy-terminal regions of MCPs are responsible for polar localization.
- The E. coli MCP, when expressed in C. crescentus, is correctly targeted to swarmer cell progeny.
- Conserved carboxy-terminal domains suggest a conserved mechanism for polar localization.
Conclusions:
- Subcellular localization of prokaryotic proteins involves specific protein regions interacting with cellular sites.
- These sites may contain localized binding proteins or a specific secretory apparatus.
- Conserved domains facilitate conserved localization mechanisms across bacterial species.