Differential Activation of Protein Kinase C Isoforms by Euxanthone, Revealed by an In Vivo Yeast Phenotypic Assay

Abstract

The protein kinase C (PKC) modulatory effects of euxanthone, isolated from the wood of Cratoxylum maingayi, on isoforms α, βI, δ, η and ζ were characterised using an alternative in vivo yeast phenotypic assay. The present study shows that euxanthone can activate isoforms α, βI, δ, η and ζ, being more effective on PKC-βI, -δ, -η and -ζ than the established PKC activators used (the phorbol ester PMA and arachidonic acid for PKC-ζ). Furthermore, euxanthone presents differences on its potency towards individual PKC isoforms, showing a remarkable selectivity for PKC-ζ. These results can help to clarify the molecular basis of the euxanthone-mediated effects.

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