Calcium ions are involved in Escherichia coli chemotaxis.
Escherichia coli regulates intracellular free Ca2+ at about 90 nM [Gangola, P. & Rosen, B. P. (1987) J. Biol. Chem. 262, 12570-12574]. To increase intracellular free Ca2+, nitr-5/Ca2+, a "caged" Ca2+ compound, was electroporated into cells and then its affinity for Ca2+ was reduced by exposure to 370-nm light. Upon release of the Ca2+ ions, the cells tumbled. Studies on mutant strains showed that the receptor proteins (methyl-accepting chemotaxis proteins, MCPs) were not required for the Ca(2+)-induced tumbling but that CheA, CheW, and CheY proteins were required. Similar results were obtained with DM-nitrophen/Ca2+, another caged calcium compound that releases Ca2+ upon illumination at 340 nm. Diazo-2, a caged Ca2+ chelator that takes up Ca2+ upon illumination at 340 nm, was used to decrease intracellular free Ca2+, and this caused smooth swimming.
Tisa
L S
LS
Department of Biochemistry, University of Wisconsin, Madison 53706.
Adler
J
J
D001426:Bacterial Proteins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002630:Chemotactic Factors / Q000502:physiology*; D002633:Chemotaxis; D003593:Cytoplasm / Q000502:physiology; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins; D000071677:Histidine Kinase; D008565:Membrane Proteins / Q000502:physiology; D000072236:Methyl-Accepting Chemotaxis Proteins
D001426:Bacterial Proteins; C489103:CheW protein, E coli; D002630:Chemotactic Factors; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; C000607606:cheY protein, E coli; C051236:CheW protein, Bacteria; C069656:CheB protein, Bacteria; D000071677:Histidine Kinase; C000607608:cheA protein, E coli; D002118:Calcium