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The pharmacophore of debromoaplysiatoxin responsible for protein kinase C activation
F H Kong1, Y Kishi, D Perez-Sala
1Department of Chemistry, Harvard University, Cambridge, MA 02138.
Abstract:
Protein kinase C is physiologically activated by 1,2-diacyl-sn-glycerol in the S configuration. The enzyme is also powerfully activated by structurally diverse tumor promotors. A model has been developed that demonstrates how the various tumor promotors and diacylglycerols can all be accommodated by the same binding site of the kinase. One prediction of this model concerns the structural nature of the pharmacophore in the tumor promotor debromoaplysiatoxin. This prediction is realized by synthesizing the analogs with the deduced pharmacophore and demonstrating that they are potent activators of protein kinase C. These findings provide strong experimental support for our structural model of protein kinase C activation.
Insights
This study reveals how protein kinase C (PKC) binds both natural activators and tumor promoters. Synthesized analogs confirm a structural model for PKC activation by diverse compounds.
Area of Science:
- Biochemistry
- Molecular Biology
- Pharmacology
Background:
- Protein kinase C (PKC) is a key enzyme in cellular signaling pathways.
- PKC is physiologically activated by 1,2-diacyl-sn-glycerol (DAG) in the S configuration.
- PKC can also be potently activated by structurally diverse tumor promoters.
Purpose of the Study:
- To develop a structural model explaining how PKC accommodates both DAG and tumor promoters in the same binding site.
- To predict the pharmacophore of the tumor promoter debromoaplysiatoxin based on the model.
- To experimentally validate the structural model through synthesis and testing of debromoaplysiatoxin analogs.
Main Methods:
- Development of a computational model for PKC activation.
- Synthesis of novel analogs based on the predicted pharmacophore of debromoaplysiatoxin.
- In vitro biochemical assays to measure the activation of PKC by synthesized analogs.
Main Results:
- The developed model successfully explains the binding of both DAG and various tumor promoters to PKC.
- Synthesized debromoaplysiatoxin analogs with the deduced pharmacophore were potent activators of PKC.
- Experimental data strongly supported the proposed structural model for PKC activation.
Conclusions:
- The findings provide robust experimental evidence for the unified structural model of PKC activation.
- The model offers insights into the mechanism of action for diverse PKC activators, including tumor promoters.
- This research paves the way for understanding and potentially targeting PKC signaling in disease contexts.