Summary
Sensor kinase and response regulator pairs that let bacteria sense and respond to environmental changes.
In depth
A membrane sensor histidine kinase autophosphorylates and transfers the phosphate to a response regulator, usually a transcription factor. They respond to osmolarity, nutrients, and antibiotics. They are absent in animals, so are potential drug targets.
Simple signalling modules found in all bacteria. They sense environment and regulate gene expression. Many control virulence.
Example: PhoQ/PhoP senses magnesium and antimicrobial peptides.
They are the main signal transduction route in bacteria, with about 30 pairs in E. coli, and also exist in archaea, fungi and plants, but not in animals. Examples: EnvZ-OmpR regulates porins according to osmolarity, PhoQ-PhoP responds to magnesium, and NarX-NarL to nitrate. Some systems control virulence, such as in Vibrio cholerae and in Staphylococcus (agr).
The histidine kinase phosphorylates on a histidine and the response regulator on an aspartate, and phosphatase activity turns the signal off. The absence from human cells makes these systems potential drug targets. Cross-talk is limited by specificity of binding.
Frequently asked questions
What is Two-Component Systems?
Sensor kinase and response regulator pairs that let bacteria sense and respond to environmental changes.
Which area of biology covers Two-Component Systems, and how advanced is it?
Two-Component Systems is one of the 54 topics in Microbiology. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Quorum Sensing, Bacterial Chemotaxis, Bacterial Cell Wall.
Why does Two-Component Systems matter?
They let cells adapt to changes in the environment with simple, modular parts, which suit synthetic biology.
Can you give an example of Two-Component Systems?
EnvZ-OmpR controls porin expression in E. coli.
What should I learn before Two-Component Systems?
Work through the Beginner topics in Microbiology first, such as Microorganisms, Bacteria, Archaea, then return to Two-Component Systems. Advanced topics assume the Intermediate vocabulary.
What topics are related to Two-Component Systems?
The closest topics to Two-Component Systems are Quorum Sensing, Bacterial Chemotaxis, Bacterial Cell Wall, Bacterial Secretion Systems. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Two-Component Systems?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Two-Component Systems. To practise the whole of Microbiology, use the Microbiology quiz.
How is Two-Component Systems different from Quorum Sensing?
Two-Component Systems: Sensor kinase and response regulator pairs that let bacteria sense and respond to environmental changes. Quorum Sensing: Bacteria release and detect signalling molecules to coordinate behaviour as population density rises. Read both side by side and note what each one explains.
How should I study Two-Component Systems step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Quorum Sensing and explain the difference aloud. Finally, take the Microbiology quiz and come back to this page for any question you miss.