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A Mass Spectrometry-Based Approach to Identify Phosphoprotein Phosphatases and their Interactors
Published on: April 29, 2022
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A conserved allosteric element controls specificity and activity of functionally divergent PP2C phosphatases from
1Department of Biochemistry, Brandeis University, Waltham, Massachusetts, USA.
The Journal of Biological Chemistry
|March 8, 2021
Summary
Protein phosphatase 2C (PP2C) activity is controlled by a conserved alpha-helical switch mechanism. This switch integrates substrate recognition with activating signals, ensuring specific dephosphorylation under correct conditions.
Area of Science:
- Biochemistry
- Molecular Biology
- Cellular Signaling
Background:
- Reversible phosphorylation regulates cellular processes via kinases and phosphatases.
- Protein phosphatase 2C (PP2C) family phosphatases are crucial regulators.
- SpoIIE and RsbU are serine/threonine phosphatases from Bacillus subtilis.
Purpose of the Study:
- To investigate the mechanism controlling protein phosphatase activity and substrate targeting.
- To determine if the alpha-helical switch mechanism in SpoIIE is conserved in other PP2C phosphatases.
- To understand how PP2C phosphatases integrate signals for specific substrate dephosphorylation.
Main Methods:
- Utilized an unbiased genetic screen to identify mutations in the RsbU alpha-helical switch region.
- Performed phosphatase activity assays using phosphoprotein substrates.
- Analyzed the role of the conserved alpha-helical element in metal cofactor binding and activation.
Main Results:
- Identified constitutively active RsbU mutants, confirming the conserved switch mechanism.
- Demonstrated that both SpoIIE and RsbU integrate substrate recognition with activating signals.
- Showed that this integration controls metal-cofactor binding, leading to substrate dephosphorylation.
Conclusions:
- The alpha-helical switch is a conserved mechanism for controlling PP2C phosphatase activity.
- Integrated control of signal activation and substrate recognition ensures specific phosphatase responses.
- This mechanism allows PP2C phosphatases to target correct substrates under appropriate conditions.
Keywords:
Bacillusallosteric regulationbacterial protein phosphatasebacterial signal transductionbacterial transcriptioncell signalingmetal ion–protein interactionprotein phosphatase 2C (PP2C)stress responsesubstrate specificityMore Related Videos
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