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Updated: Jan 6, 2026
09:51
Purification of a High Molecular Mass Protein in Streptococcus mutans
Published on: September 14, 2019
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Post-translational modifications via serine/threonine phosphorylation and GpsB in Streptococcus mutans
Sangam Chudal1, Courtney Dover1, Tiffany Haydt1,2
1Department of Biological Sciences, Beck College of Sciences and Mathematics, Arkansas State University, Jonesboro, Arkansas, USA.
Msystems
|October 30, 2025
Summary
This study reveals widespread O-phosphorylation in Streptococcus mutans, crucial for bacterial growth and function. Disrupting the GpsB protein highlights its role in regulating essential phosphorylation events, offering potential targets for combating cavities.
Area of Science:
- Bacteriology
- Molecular Biology
- Biochemistry
Background:
- Post-translational modifications (PTMs) like protein phosphorylation are key regulators of bacterial physiology.
- Streptococcus mutans is a common bacterium responsible for tooth decay.
Purpose of the Study:
- To conduct a comprehensive phosphoproteomic analysis of S. mutans.
- To investigate the roles of the serine/threonine protein kinase (PknB) and phosphatase (PppL) in S. mutans.
- To understand the regulatory role of GpsB in bacterial phosphorylation.
Main Methods:
- Tandem mass tag (TMT)-based mass spectrometry for phosphoproteomics.
- Phosphopeptide enrichment techniques.
- Analysis of phosphoproteomic and proteomic changes in gene deletion mutants (ΔpknB and ΔpppL).
Main Results:
- Identified 231 high-confidence phosphosites on 131 proteins in S. mutans.
- Phosphorylated proteins are involved in translation, carbohydrate metabolism, and cell cycle.
- Mutants lacking PknB or PppL showed significant alterations in protein phosphorylation and abundance.
- Disruption of GpsB led to lethal defects, which could be rescued by a mutation in PppL, restoring DivIVA phosphorylation.
Conclusions:
- O-phosphorylation plays a broad role in core S. mutans cellular functions.
- PknB and PppL are key regulators of the S. mutans phosphoproteome.
- GpsB regulates the PknB/PppL signaling axis to control essential target phosphorylation, impacting bacterial survival.
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