Conformationally Constrained Analogues of Diacylglycerol (DAG). 28. DAG-dioxolanones Reveal a New Additional Interaction Site in the C1b Domain of PKCδ
摘要:
Diacylglycerol (DAG) lactones have provided a powerful platform for structural exploration of the interactions between ligands and the C1 domains of protein kinase C (PKC). In this study, we report that DAG-dioxolanones, novel derivatives of DAG-lactones, exploit an additional point of contact (glutamine 27) in their binding with the C1b domain of PKC delta. Mutation of this point of contact to glutamate selectively impairs binding of the DAG-dioxolanones compared to that of the corresponding DAG-lactones (1200- to 3000-fold versus 35- to 55-fold, respectively). The differential response of this mutated C1b domain to the DAG-dioxolanones relative to the DAG-lactones provides a unique tool to probe the role of the C1b domain in PKC delta function, where the response to the DAG-lactones affords a positive control for retained function. Using this approach, we show that the C1b domain of PKC delta plays the predominant role in the translocation of PKC delta to the membrane in the presence of DAG.
Design and synthesis of protein kinase C epsilon selective diacylglycerol lactones (DAG-lactones)
摘要:
DAG-lactones afford a synthetically accessible, high affinity platform for probing structure activity relationships at the Cl regulatory domain of protein kinase C (PKC). Given the central role of PKC isoforms in cellular signaling, along with their differential biological activities, a critical objective is the design of isoform selective ligands. Here, we report the synthesis of a series of DAG-lactones varying in their side chains, with a particular focus on linoleic acid derivatives. We evaluated their selectivity for PKC epsilon versus PKC alpha both under standard lipid conditions (100% phosphatidylserine, PS) as well as in the presence of a nuclear membrane mimetic lipid mixture (NML). We find that selectivity for PKC epsilon versus PKC alpha tended to be enhanced in the presence of the nuclear membrane mimetic lipid mixture and, for our lead compound, report a selectivity of 32-fold. (C) 2014 Elsevier Masson SAS. All rights reserved.