The Staphylococcus aureus Membrane Protein SA2056 Interacts with Peptidoglycan Synthesis Enzymes

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• The Resistance-Nodulation-cell Division (RND) family comprises transmembrane efflux transporters with diverse functions.
• The staphylococcal cell wall pentaglycine interpeptide synthesis involves essential enzymes like FemX and FemB.
• The function of the uncharacterized RND protein SA2056, located near femX, was investigated in relation to peptidoglycan synthesis.

Purpose of the Study:

• To characterize the novel membrane protein SA2056 and its role in Staphylococcus aureus.
• To investigate the potential involvement of SA2056 in peptidoglycan synthesis due to its genetic proximity to femX.
• To identify interaction partners of SA2056 within the bacterial cell.

Main Methods:

• Antibodies were generated against SA2056 to confirm its expression and localization.
• A bacterial two-hybrid system was employed to identify SA2056 interaction partners.
• Gene deletion mutants (sa2056 and sa2056 femB) were created and analyzed for phenotypic changes.

Main Results:

• SA2056 is expressed during growth and localized to the membrane fraction.
• SA2056 interacts with itself, FemB, PBP1, and PBP2, proteins crucial for cell wall synthesis.
• Deletion of sa2056 did not result in observable phenotypes in growth, antibiotic resistance, or cell morphology, even in combination with femB inactivation.

Conclusions:

• SA2056, an RND family protein, likely plays an accessory role in Staphylococcus aureus peptidoglycan synthesis.
• The lack of a significant phenotype upon sa2056 deletion suggests functional redundancy in cell wall biosynthesis pathways.
• These findings expand the known biological functions of RND proteins beyond typical efflux mechanisms.