Can small compounds modulate the mechanism of regulation of novel and atypical PKCs?

SUESS, EVELYN; KAZANIETZ, MARCELO; SACERDOTI, MARIANA; LEROUX, ALEJANDRO E.; GROSS, LISSY; BARRIO REAL, LAURA; BIONDI, RICARDO M.

Bariloche

Congreso; South American Spring Symposium in Signal Transduction and Molecular Medicine 2018; 2018

Proteinkinases play important regulatory roles in cells and organisms. Therefore, theyare subject to specific and tight mechanisms of regulation. The Protein kinaseC (PKC) comprises 10 isoforms, classified in classical, novel and atypical. Incommon, all isoforms are inhibited and regulated by an N-terminal region. PKCsplay roles in cancer, inflammation and other health conditions. Therefore,there has been significant interest in targeting different PKC isoforms fordeveloping drugs in the treatment of diverse diseases. Nevertheless, the mostfrequently used target is the evolutionary conserved ATP-binding-site. Thechallenge throughout the years has been to develop selective inhibitors of PKCisoforms. Over the years, we described aspects of the molecular mechanism ofregulation of atypical PKCs where the C1 domain binds to the small lobe of thekinase and importantly participates in the inhibition of the activity. Inaddition, we described small compounds that bind to a regulatory site(PIF-pocket) on the small lobe of the kinase domain and allosterically inhibitkinase activity by modulating the conformation of the active site. The detailsof the molecular mechanism of regulation of PKC isoforms are being completed,but certain aspects are still controversial. It remains particularly unclearwhich parts of the mechanisms are conserved, and which differ between the differentisoforms. Based on our experience on atypical PKCs, we set to investigate if wecould also modulate the activity of other PKC isoforms with small compounds. Inour ongoing work, we expressed and purified the isolated catalytic domain ofPKC epsilon and different isolated N-terminal constructs. We then set-up an interactionassay and screened a small library of compounds for molecules that wouldenhance or inhibit this interaction. We will present our ongoing results and wewill discuss the possibilities for allosteric regulation of specific PKCisoforms with small molecules.