Transmembrane signaling. Mutational analysis of the cytoplasmic linker region of Taz1-1, a Tar-EnvZ chimeric receptor in Escherichia coli

Tian Jin, Masayori Inouye

Research output: Contribution to journalEditorialpeer-review

23 Scopus citations

Abstract

Taz1-1 is Tar-EnvZ chimeric receptor that is able to induce ompC-lacZ expression in response to aspartate. Previous studies indicated that aspartate binding to the receptor domain of the Taz1-1 receptor modulated the ratio of kinase and phosphatase activities of the cytoplasmic signaling domain. The 80-residue segment of chemoreceptors that is located between the second transmembrane domain and the signaling domain was defined as the linker region. The Taz1-1 chimeric receptor contains 43 amino acid residues of the Tar linker region. In order to understand further the function of the linker region in transmembrane signaling, site-directed random mutagenesis was carried out on the conserved Ala231 in the linker region. Substitution mutations with Val, Glu, Gly, Thr, Lys and His gave the locked “off-mode” form (low ompC-lacZ expression), and substitution mutations with Ile and Leu resulted in the locked “on-mode” form (constitutive ompC-lacZ expression). All the mutant Taz1-1 receptors still retained both OmpR kinase and phospho-OmpR phosphatase activities. Interestingly Taz1NG6 a kinase defective mutant, was able to complement with Taz1H1, a phosphatase defective mutant, carrying an off-mode mutant at position 231 to restore Asp-inducible ompC-lacZ expression, but not with Taz1H1 carrying an on-mode mutation. These results suggest that the residue at position 231 in Taz1-1 plays a key role in signal transduction.

Original languageEnglish (US)
Pages (from-to)477-481
Number of pages5
JournalJournal of molecular biology
Volume244
Issue number5
DOIs
StatePublished - Dec 15 1994

All Science Journal Classification (ASJC) codes

  • Structural Biology
  • Molecular Biology

Keywords

  • Chemosensor
  • Histidine kinase
  • Phosphatase
  • Receptor
  • Transmembrane signaling

Fingerprint Dive into the research topics of 'Transmembrane signaling. Mutational analysis of the cytoplasmic linker region of Taz1-1, a Tar-EnvZ chimeric receptor in Escherichia coli'. Together they form a unique fingerprint.

Cite this