Two distinct families of protein kinases are involved in signal transduction: Ser, Thr and Tyr kinases, which are predominantly found among eukaryotes, and His kinases, as part of bacterial two-component signalling systems. Genetic studies in Arabidopsis and Saccharomyces have demonstrated that bacterial-type two-component systems may act upstream of Ser/Thr kinases in the same signalling pathway, but how this coupling is accomplished remains unclear. In the present study, we report the characterization of a protein kinase, HstK, from the N2-fixing cyanobacterium Anabaena sp. PCC 7120, that possesses both a Ser/Thr kinase domain and a His kinase domain. Proteins with a structural architecture similar to that of HstK can be found in the eukaryote, Schizosaccharomyces pombe, and the bacterium, Rhodococcus sp. M5. HstK was present in cells grown with NH4+ or N2 as the nitrogen source, but was absent in cells grown with NO3−. The hstK gene was inactivated and the mutant phenotype was characterized. The catalytic domain of the Ser/Thr kinase of HstK functionally replaced that of Hog1p, a well-characterized protein kinase required for the response to high osmolarity in the S. cerevisiae heterologous system. The unusual multidomain structure of HstK suggests that a two-component system could be directly coupled to Ser/Thr kinases in the same signal transduction pathway.
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December 2001
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Research Article|
December 10 2001
HstK, a cyanobacterial protein with both a serine/threonine kinase domain and a histidine kinase domain: implication for the mechanism of signal transduction
Vincent PHALIP;
Vincent PHALIP
∗Unité d'Immunotechnologie et Microbiologie Moléculaire, Ecole Superieure de Biotechnologie de Strasbourg, Université Louis Pasteur de Strasbourg, Boulevard Sebastien Brandt, F-67400 Illkirch, France
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Jian-Hong LI;
Jian-Hong LI
†Laboratoire de Chimie Bactérienne (UPR9043), C.N.R.S., 31 Chemin Joseph Aiguier, Marseille cedex 20, France
‡College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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Cheng-Cai ZHANG
Cheng-Cai ZHANG
1
†Laboratoire de Chimie Bactérienne (UPR9043), C.N.R.S., 31 Chemin Joseph Aiguier, Marseille cedex 20, France
‡College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
1To whom correspondence should be addressed (e-mail cczhang@ibsm.cnrs-mrs.fr).
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Publisher: Portland Press Ltd
Received:
August 03 2001
Revision Received:
September 17 2001
Accepted:
October 11 2001
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London ©2001
2001
Biochem J (2001) 360 (3): 639–644.
Article history
Received:
August 03 2001
Revision Received:
September 17 2001
Accepted:
October 11 2001
Citation
Vincent PHALIP, Jian-Hong LI, Cheng-Cai ZHANG; HstK, a cyanobacterial protein with both a serine/threonine kinase domain and a histidine kinase domain: implication for the mechanism of signal transduction. Biochem J 15 December 2001; 360 (3): 639–644. doi: https://doi.org/10.1042/bj3600639
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