Role of threonine residues in the regulation of manganese-dependent arabidopsis serine/threonine/tyrosine protein kinase activity

Reddy, Mamatha M and Rajasekharan, Ram (2006) Role of threonine residues in the regulation of manganese-dependent arabidopsis serine/threonine/tyrosine protein kinase activity. In: Archives of Biochemistry and Biophysics, 455 (2). pp. 99-109.

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Abstract

Tyrosine phosphorylation in plants could be performed only by dual-specificity kinases. Arabidopsis thaliana dual-specificity protein kinase (AtSTYPK) exhibited strong preference for manganese over magnesium for its kinase activity. The kinase autophosphorylated on serine, threonine and tyrosine residues and phosphorylated myelin basic protein on threonine and tyrosine residues. The AtSTYPK harbors manganese dependent serine/threonine kinase domain, COG3642. $His^{248}$ and $Ser^{265}$ on COG3642 are conserved in AtSTYPK and the site-directed mutant, H248A showed loss of serine/threonine kinase activity. The protein kinase activity was abolished when $Thr^{208}$ in the TEY motif and $Thr^{293}$ of the activation loop were converted to alanine. The conversion of $Thr^{284}$ in the activation loop to alanine resulted in an increased phosphorylation. This study reports the first identification of a manganese dependent dual-specificity kinase and the importance of $Thr^{208}, Thr^{284}$, and $Thr^{293}$ residues in the regulation of kinase activity.

Item Type:	Journal Article
Publication:	Archives of Biochemistry and Biophysics
Publisher:	Elsevier
Additional Information:	Copyright of this article belongs to Elsevier.
Keywords:	Plant dual-speciWcity protein kinase;Regulation of protein kinase activity;Site-directed mutagenesis;MALDI mass spectrometry;Protein phosphorylation
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	21 Dec 2006
Last Modified:	19 Sep 2010 04:33
URI:	http://eprints.iisc.ac.in/id/eprint/9178

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