A biomolecular proportional integral controller based on feedback regulations of protein level and activity.
Francis MairetPublished in: Royal Society open science (2018)
Homeostasis is the capacity of living organisms to keep internal conditions regulated at a constant level, despite environmental fluctuations. Integral feedback control is known to play a key role in this behaviour. Here, I show that a feedback system involving transcriptional and post-translational regulations of the same executor protein acts as a proportional integral (PI) controller, leading to enhanced transient performances in comparison with a classical integral loop. Such a biomolecular controller-which I call a level and activity-PI controller (LA-PI)-is involved in the regulation of ammonium uptake by Escherichia coli through the transporter AmtB. The P II molecules, which reflect the nitrogen status of the cell, inhibit both the production of AmtB and its activity (via the NtrB-NtrC system and the formation of a complex with GlnK, respectively). Other examples of LA-PI controller include copper and zinc transporters, and the redox regulation in photosynthesis. This scheme has thus emerged through evolution in many biological systems, surely because of the benefits it offers in terms of performances (rapid and perfect adaptation) and economy (protein production according to needs).
Keyphrases
- escherichia coli
- transcription factor
- protein protein
- amino acid
- binding protein
- gene expression
- single cell
- mesenchymal stem cells
- oxidative stress
- small molecule
- climate change
- brain injury
- bone marrow
- ionic liquid
- cell therapy
- cystic fibrosis
- subarachnoid hemorrhage
- gram negative
- heat stress
- heat shock protein
- heat shock
- klebsiella pneumoniae