Delayed phosphorylation of classical protein kinase C (PKC) substrates requires PKC internalization and formation of the pericentrion in a phospholipase D (PLD)-dependent manner.

It was previously demonstrated that sustained activation (30-60 min) of protein kinase C (PKC) results in translocation of PKC α and βII to the pericentrion, a dynamic subset of the recycling compartment whose formation is dependent on PKC and phospholipase D (PLD). Here we investigated whether the formation of the pericentrion modulates the ability of PKC to phosphorylate substrates, especially if it reduces substrate phosphorylation by sequestering PKC. Surprisingly, using an antibody that detects phosphosubstrates of classical PKCs, the results showed that the majority of PKC phosphosubstrates are phosphorylated with delayed kinetics, correlating with the time frame of PKC translocation to the pericentrion.

SKN1, a novel plant defensin-sensitivity gene in Saccharomyces cerevisiae, is implicated in sphingolipid biosynthesis.

The antifungal plant defensin DmAMP1 interacts with the fungal sphingolipid mannosyl diinositolphosphoryl ceramide (M(IP)(2)C) and induces fungal growth inhibition. We have identified SKN1, besides the M(IP)(2)C-biosynthesis gene IPT1, as a novel DmAMP1-sensitivity gene in Saccharomyces cerevisiae. SKN1 was previously shown to be a KRE6 homologue, which is involved in beta-1,6-glucan biosynthesis.