Protein Kinase C (PKC) is a multigene family of serine/threonine kinases with major roles in carcinogenesis, due to their involvement in the regulation of key cellular processes, as survival and apoptosis. This makes these proteins promising targets in anticancer therapy [reviewed in (Koivunen et al., 2006)]. However, the high complexity of the PKC signalling pathway in mammalian cells has hampered the study of the role of each isoform in cellular processes.

To circumvent this limitation, several growth-inhibitory assays using yeast cells expressing individual PKC isoforms were developed. With these assays, the potency and isoform-selectivity of well-known PKC activators and inhibitors were characterized.

New PKC modulators were discovered [reviewed by (Pereira et al., 2012b; Silva et al. 2012)], namely the diterpene compound 6,11,12,14-tetrahydroxy-abieta-5,8,11,13-tetraene-7-one (coleon U), a potent and selective activator of the novel PKCδ and ε [Coutinho et al., Biochem Pharmacol, 2009; Portuguese Patent nº103977 (Refª DP/01/2008/8482)], and the selective activator of PKCδ, the compound Roy-Bz [National Patent Request PPP Nº 109140 (2016/02/05-13)].

In addition, the involvement of PKC isoforms in the regulation of wild-type p53 activity was confirmed by our group using yeast cells co-expressing human wild-type p53 and a PKC isoform (α, δ, ε, ζ) (Coutinho et al., FEBS Lett, 2009; Coutinho et al., Exp Cell Res, 2011).