Histidin-specific protein kinase

Histidine-specific protein kinases form a phosphorus amide with the 1 or 3 position of His. The members of this enzyme family also phosphorylate Lys and Arg residues. 

The two-component pathway is characterized by two functional elements. A histidine-specific protein kinase functions as a sensor that registers an external signal and passes this on to a downstream response regulator. The latter is activated by phosphorylation during the process of signal transduction, triggering other reactions in the cell (Fig. 12.3). 

HISK, histidine-specific protein kinase HIS-R, histamine receptor HIV-1, human immunodeficiency virus 1 HIV-1 IN, HIV-1 integrase HIV-1 PR, HIV-1 protease HIV-1 RT, HIV-1 reverse transcriptase HMG protein, high mobility group protein... 

The control of cellular proliferation and differentiation in response to external stimuli is achieved by signal transduction pathways, which are regulated in part by the co-ordinated action of protein kinases and phosphatases. In eukaryotic cells the protein kinases involved fall primarily into two classes, those that phosphorylate tyrosine residues and those that are specific for serine and threonine residues. Prokaryotic cells also rely on protein phosphorylation cascades for regulation of cellular activities, but the kinases involved are primarily histidine kinases, which are part of the sensing domain of two-component regulatory systems. These histidine kinases and their associated response regulators are involved in a range of adaptive responses by bacteria. 

Mourad-Terzian, T. Steghens, J.P. Min, K.L. Collombel, C. Bozon, D. Creatine kinase isoenzymes specificities histidine 65 in human CK-BB, a role in protein stability, not in catalysis. FEBS Lett., 475, 22-26 (2000)... 

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