The surface-located YopN protein is involved in calcium signal transduction in Yersinia pseudotuberculosis

Mol Microbiol. 1991 Apr;5(4):977-86. doi: 10.1111/j.1365-2958.1991.tb00773.x.


The low-calcium response (lcr) is strongly conserved among the pathogenic Yersinia species and is observed when the pathogen is grown at 37 degrees C in Ca(2+)-depleted medium. This response is characterized by a general metabolic downshift and by a specific induction of virulence-plasmid-encoded yop genes. Regulation of yop expression is exerted at transcriptional level by a temperature-regulated activator and by Ca(2+)-regulated negative elements. The yopN gene was shown to encode a protein (formerly also designated Yop4b) which is surface-located when Yersinia is grown at 37 degrees C. yopN was found to be part of an operon that is induced during the low-calcium response. Insertional inactivation of the yopN gene resulted in derepressed transcription of yop genes. A hybrid plasmid containing the yopN gene under the control of the tac promoter fully restored the wild-type phenotype of the yopN mutant. Thus the surface-located YopN somehow senses the calcium concentration and transmits a signal to shut off yop transcription when the calcium concentration is high.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / analysis
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Blotting, Northern
  • Calcium / metabolism*
  • DNA Mutational Analysis
  • Gene Expression Regulation, Bacterial
  • Genetic Complementation Test
  • Immunoblotting
  • Membrane Proteins*
  • Molecular Sequence Data
  • Plasmids / genetics
  • Repressor Proteins / physiology
  • Restriction Mapping
  • Signal Transduction*
  • Temperature
  • Transcription Factors / physiology
  • Transcription, Genetic
  • Yersinia pseudotuberculosis / metabolism*
  • Yersinia pseudotuberculosis / pathogenicity


  • Bacterial Proteins
  • Membrane Proteins
  • Repressor Proteins
  • Transcription Factors
  • YopN protein, Yersinia
  • Calcium

Associated data

  • GENBANK/X51833