ClpV recycles VipA/VipB tubules and prevents non‐productive tubule formation to ensure efficient type VI protein secretion. Issue 5 (3rd February 2013)

• Record Type: Journal Article
• Authors: Kapitein, Nicole; Bönemann, Gabriele; Pietrosiuk, Aleksandra; Seyffer, Fabian; Hausser, Ingrid; Locker, Jacomine Krijnse; Mogk, Axel
• Is Part Of: Molecular microbiology. Volume 87:Issue 5(2013)
• Page Start: 1013
• Page End: 1028
• Publication Date: 2013-02-03
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.12147
• Languages: English
• ISSNs: 0950-382X

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>The multicomponent type VI secretion system (T6SS) mediates the transport of effector proteins by puncturing target membranes. T6SSs are suggested to form a contractile nanomachine, functioning similar to the cell‐puncturing device of tailed bacteriophages. The T6SS members VipA/VipB form tubular complexes and are predicted to function in analogy to viral tail sheath proteins by providing the energy for secretion via contraction. The ATPase ClpV disassembles VipA/VipB tubules <italic>in vitro</italic>, but the physiological relevance of tubule disintegration remained unclear. Here, we show that VipA/VipB tubules localize near‐perpendicular to the inner membrane of <italic>Vibrio cholerae</italic> cells and exhibit repetitive cycles of elongation, contraction and disassembly. VipA/VipB tubules are decorated by ClpV <italic>in vivo</italic> and become static in Δ<italic>clpV</italic> cells, indicating that ClpV is required for tubule removal. VipA/VipB tubules mislocalize in Δ<italic>clpV</italic> cells and exhibit a reduced frequency of tubule elongation, indicating that ClpV also suppresses the spontaneous formation of contracted, non‐productive VipA/VipB tubules. ClpV activity is restricted to the contracted state of VipA/VipB, allowing formation of functional elongated tubules at a T6SS assembly. Targeting of an unrelated ATPase to VipA/VipB is sufficient to replace ClpV function <italic>in vivo</italic>, suggesting that ClpV activity is autonomously regulated by VipA/VipB conformation.</p> </abstract>