Protein PII regulates both inorganic carbon and nitrate uptake and is modified by a redox signal in synechocystis PCC 6803

FEBS Lett. 1999 Dec 17;463(3):216-20. doi: 10.1016/s0014-5793(99)01624-5.


In Synechocystis PCC 6803 as in other cyanobacteria, involvement of protein PII in the co-regulation of inorganic carbon and nitrogen metabolism was established based on post-translational modifications of the protein resulting from changes in the carbon/nitrogen regimes. Uptake of bicarbonate and nitrate in response to changes of the carbon and/or nitrogen regimes is altered in a PII-null mutant, indicating that both processes are under control of PII. Modulation of electron flow by addition of methyl viologen with or without duroquinol, or in a NAD(P)H dehydrogenase-deficient mutant, affects the phosphorylation level of PII. The redox state of the cells would thus act as a trigger for PII phosphorylation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / pharmacology*
  • Bicarbonates / metabolism
  • Cyanobacteria / drug effects*
  • Cyanobacteria / genetics
  • Cyanobacteria / metabolism
  • Hydroquinones
  • NADPH Dehydrogenase / deficiency
  • NADPH Dehydrogenase / genetics
  • Nitrates / metabolism
  • Oxidation-Reduction
  • PII Nitrogen Regulatory Proteins
  • Paraquat
  • Phosphorylation
  • Protein Kinases / metabolism


  • Bacterial Proteins
  • Bicarbonates
  • Hydroquinones
  • Nitrates
  • PII Nitrogen Regulatory Proteins
  • PIID regulatory protein, Bacteria
  • NADPH Dehydrogenase
  • Protein Kinases
  • Paraquat
  • duroquinol