Download MendeleyCtpb Assembles a Gated Protease Tunnel Regulating Cell-Cell Signaling During Spore Formation in Bacillus Subtilis.
Mastny, M., Heuck, A., Kurzbauer, R., Heiduk, A., Boisguerin, P., Volkmer, R., Ehrmann, M., Rodrigues, C.D.A., Rudner, D.Z., Clausen, T.(2013) Cell 155: 647
- PubMed: 24243021
- DOI: https://doi.org/10.1016/j.cell.2013.09.050
- Primary Citation of Related Structures:
4C2C, 4C2D, 4C2E, 4C2F, 4C2G, 4C2H - PubMed Abstract:
Spore formation in Bacillus subtilis relies on a regulated intramembrane proteolysis (RIP) pathway that synchronizes mother-cell and forespore development. To address the molecular basis of this SpoIV transmembrane signaling, we carried out a structure-function analysis of the activating protease CtpB. Crystal structures reflecting distinct functional states show that CtpB constitutes a ring-like protein scaffold penetrated by two narrow tunnels. Access to the proteolytic sites sequestered within these tunnels is controlled by PDZ domains that rearrange upon substrate binding. Accordingly, CtpB resembles a minimal version of a self-compartmentalizing protease regulated by a unique allosteric mechanism. Moreover, biochemical analysis of the PDZ-gated channel combined with sporulation assays reveal that activation of the SpoIV RIP pathway is induced by the concerted activity of CtpB and a second signaling protease, SpoIVB. This proteolytic mechanism is of broad relevance for cell-cell communication, illustrating how distinct signaling pathways can be integrated into a single RIP module.
Organizational Affiliation:
Research Institute of Molecular Pathology, 1030 Vienna, Austria.
