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Updated: Aug 30, 2026

Characterization at the Molecular Level using Robust Biochemical Approaches of a New Kinase Protein
Published on: June 30, 2019
Role of the kinase activation loop on protein kinase C theta activity and intracellular localisation
Bianca Sparatore1, Mario Passalacqua, Marco Pedrazzi
1Department of Experimental Medicine, Biochemistry Section, University of Genoa, Viale Benedetto XV, 16132 Genoa, Italy. traspar@unige.it
Abstract:
Multiple protein kinase C (PKC) theta species, identified in an erythroleukaemia cell line, have been characterised in terms of their molecular properties and intracellular distribution. PKCthetas localised in the detergent-soluble cell fraction have an Mr of 76 kDa (theta-76) and contain Thr538 or pThr538 in the kinase activation loop. In contrast, PKCthetas localised in the Golgi complex have an Mr of 85 kDa (theta-85) and, although unphosphorylated at Thr538, are catalytically active. Strikingly, only theta-76 species which are unphosphorylated at Thr538 can undergo autocatalytic conversion to theta-85. Moreover, a Thr538-->Ala PKCtheta mutant is constitutively localised in the Golgi complex, confirming that changes in the phosphorylation state of this residue play a pivotal role in the overall control of catalytic properties and localisation of this kinase.
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