Role of the processing pore of the ClpX AAA+ ATPase in the recognition and engagement of specific protein substrates

  1. Samia M. Siddiqui1,
  2. Robert T. Sauer1, and
  3. Tania A. Baker1,2,3
  1. 1Massachusetts Institute of Technology, Department of Biology, 2Howard Hughes Medical Institute, Cambridge, Massachusetts 02139, USA

Abstract

ClpX binds substrates bearing specific classes of peptide signals, denatures these proteins, and translocates them through a central pore into ClpP for degradation. ClpX with the V154F pore mutation is severely defective in binding substrates bearing C-motif 1 degradation signals and is also impaired in a subsequent step of substrate engagement. In contrast, this mutant efficiently processes substrates with other classes of recognition signals both in vitro and in vivo. These results demonstrate that the ClpX pore functions in the recognition and catalytic engagement of specific substrates, and that ClpX recognizes different substrate classes in at least two distinct fashions.

Keywords

Footnotes

  • Article and publication are at http://www.genesdev.org/cgi/doi/10.1101/gad.1170304.

  • 3 Corresponding author.

    3 E-MAIL tabaker{at}mit.edu; FAX (617) 252-1852.

    • Accepted December 30, 2003.
    • Received November 17, 2003.
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