Staphylococcus aureus encodes four differentially regulated pyruvate transporters

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Staphylococcus aureus relies on diverse nutrient sources for pathogenesis.
• Pyruvate metabolism is crucial for bacterial energy production and biosynthesis.
• Previous understanding of pyruvate import in S. aureus was limited to microaerobic conditions (LrgAB).

Purpose of the Study:

• To identify pyruvate transporters responsible for aerobic growth in S. aureus.
• To investigate the role of LctP and LldP in pyruvate uptake.
• To characterize the complete network of pyruvate transporters in S. aureus.

Main Methods:

• Utilized a toxic pyruvate analog (3-fluoropyruvic acid) to select for mutants with impaired pyruvate uptake.
• Performed whole-genome sequencing (WGS) to identify mutations.
• Conducted 14C-pyruvate uptake assays and growth studies.
• Genetically inactivated identified transporter genes.

Main Results:

• Identified lctP and lldP as functional pyruvate transporters, despite initial annotation as lactate permeases.
• Discovered B7H15_13955 (an MFS transporter) as a fourth pyruvate transporter.
• Demonstrated that inactivation of all four transporters (LrgAB, LctP, LldP, B7H15_13955) completely abolished pyruvate uptake.
• Showed that S. aureus employs multiple pyruvate transporters for aerobic and anaerobic conditions.

Conclusions:

• S. aureus possesses a complex, multi-component system for pyruvate acquisition.
• LctP, LldP, and B7H15_13955, alongside LrgAB, form a regulated network for pyruvate import.
• This finding enhances understanding of S. aureus metabolic flexibility and virulence.