Science, Technology and Engineering

Dougan & Truscott Laboratory

Department of Biochemistry

Research- Adaptor-mediated substrate delivery

An important principle that has recently emerged in this field is that the range of protein targets of AAA+ proteases can be extended by specific adaptor proteins. These co-factors transfer substrate specificity to the interacting unfoldase in a trans-targeting mechanism. A major focus of our lab is directed towards an analysis of novel AAA+ adaptor proteins and how these protein co-factors modulate AAA+ substrate specificity. Previous research highlights in this area carried out by investigator Dougan, while in the lab of Bernd Bukau, include the identification of a novel E. coli adaptor protein, ClpS that "switches" the activity of the ClpAP machine by binding directly to the N-terminal domain of ClpA (Dougan et al., 2002). Together with Kornelius Zeth at the Max Planck Institute of Biochemistry in Germany we solved the 3-dimensional structure of ClpS in complex with the interacting domain of ClpA (Zeth et al., 2002). Most recently we showed that ClpS is an essential component of the N-end rule pathway in E. coli (Erbse et al., 2006). Elucidation of the physiological N-end rule substrates of the ClpAPS protease awaits further research. Recently the mechanistic details (see below) by which SsrA-tagged proteins are delivered by the adaptor protein SspB to the ClpXP machine in E. coli were elucidated (Dougan et al., 2003). Our interest in adaptors of AAA+ proteases also extends to Bacillus subtilis, through a collaboration with Assoc. Prof. Kursad Turgay. Our research group is currently studying new adaptor proteins and substrates with the aim of obtaining a detailed understanding of the AAA+ protease network.

Recent publications

• Ninnis RL, Spall SK, Talbo GH, Truscott KN, Dougan DA. (2009). Modification of PATase by L/F-transferase generates a ClpS-dependent N-end rule substrate in Escherichia coli.
  EMBO J. 28, 1732-1744.
• Schuenemann VJ, Kralik SM, Albrecht R, Spall SK, Truscott KN, Dougan DA, Zeth K. (2009). Structural basis of N-end rule substrate recognition in Escherichia coli by the ClpAP adaptor protein ClpS. EMBO Reports 10, 508-514.
• Kirstein J, Dougan DA, Gerth U, Hecker M, Turgay K. (2007).
  The tyrosine kinase McsB is a regulated adaptor protein for ClpCP.EMBO J. 26, 2061-2070.
• Kirstein J, Schlothauer T, DOUGAN DA, Lilie H, Tischendorf G, Mogk A, Bukau B, Turgay K. (2006). Adaptor protein controlled oligomerization activates the AAA+ protein ClpC. EMBO J., 5, 1481-1491.
• Erbse A, Schmidt R, Bornemann T, Schneider-Mergener J, Mogk A, Zahn R, DOUGAN DA, Bukau B. (2006).
  ClpS is an essential component of the N-end rule pathway in Escherichia coli. Nature 439, 753-6.
• DOUGAN DA, Weber-Ban E, Bukau B. (2003). Targeted delivery of an ssrA-tagged substrate by the adaptor protein SspB to its cognate AAA+ protein ClpX. Mol Cell. 12, 373-80.
• Zeth K, Ravelli RB, Paal K, Cusack S, Bukau B, DOUGAN DA. (2002). Structural analysis of the adaptor protein ClpS in complex with the N-terminal domain of ClpA. Nat. Struct. Biol. 9, 906-11.
• DOUGAN DA, Reid BG, Horwich AL, Bukau B. (2002). ClpS, a substrate modulator of the ClpAP machine. Mol Cell. 9, 673-83.

Collaborators

Bernd Bukau (ZMBH, Heidelberg, Germany)
Art Horwich (Yale University, Connecticut, U.S.A.)
Kursad Turgay (Freie University Berlin, Germany)
Eilika Weber-Ban (ETH, Zurich, Switzerland)
Kornelius Zeth (MPI for Developmental Biology, Tübingen, Germany)