Regulation of Type VI Secretion Systems of Burkholderia during transition to intracellular lifestyle.

Burkholderia thailandensis switches from anti-bacterial T6SS-1 to anti-eukaryotic T6SS-5 during host cell invasion, with T6SS-1 activity causing host cell damage.

• Why it matters: Understanding how pathogenic bacteria regulate their secretion systems during infection can reveal strategies to prevent or treat bacterial diseases. The transition between T6SS types influences bacterial survival and pathogenicity within host cells.
• What they did: The study examined gene expression and assembly of T6SS-1 and T6SS-5 in B. thailandensis during phagosomal maturation, using genetic deletions and cellular assays to track their regulation and effects.
• The result: Findings show that T6SS-5 expression, controlled by VirAG, suppresses T6SS-1 assembly, preventing host cell damage and enabling bacterial replication, highlighting a sophisticated regulatory mechanism during infection.