title: Molecular systems pharmacology: isoelectric focusing signature of protein kinase Cδ provides an integrated measure of its modulation in response to ligands.
abstract: Protein kinase C (PKC), a validated therapeutic target for cancer chemotherapy, provides a paradigm for assessing structure-activity relations, where ligand binding has multiple consequences for a target. For PKC, ligand binding controls not only PKC activation and multiple phosphorylations but also subcellular localization, affecting subsequent signaling. Using a capillary isoelectric focusing immunoassay system, we could visualize a high resolution isoelectric focusing signature of PKCδ upon stimulation by ligands of the phorbol ester and bryostatin classes. Derivatives that possessed different physicochemical characteristics and induced different patterns of biological response generated different signatures. Consistent with different patterns of PKCδ localization as one factor linked to these different signatures, we found different signatures for activated PKCδ from the nuclear and non-nuclear fractions. We conclude that the capillary isoelectric focusing immunoassay system may provide a window into the integrated consequences of ligand binding and thus afford a powerful platform for compound development.
authors.affiliation: Laboratory of Cancer Biology and Genetics, ‡Collaborative Protein Technology Resource, Laboratory of Cell Biology, and §Office of Science and Technology Partnerships, Center for Cancer Research, National Cancer Institute , Bethesda, Maryland 20892, United States.
authors.forename: Noemi
authors.initials: N
authors.lastname: Kedei
authors.forename: Jin-Qiu
authors.initials: JQ
authors.lastname: Chen
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Herrmann
authors.forename: Andrea
authors.initials: A
authors.lastname: Telek
authors.forename: Paul K
authors.initials: PK
authors.lastname: Goldsmith
authors.forename: Mark E
authors.initials: ME
authors.lastname: Petersen
authors.forename: Gary E
authors.initials: GE
authors.lastname: Keck
authors.forename: Peter M
authors.initials: PM
authors.lastname: Blumberg
mesh_terms: D054713:Bryostatins / Q000378:metabolism*; D045744:Cell Line, Tumor; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007525:Isoelectric Focusing; D008024:Ligands; D010703:Phorbol Esters / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D051745:Protein Kinase C-delta / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D054713:Bryostatins; D008024:Ligands; D010703:Phorbol Esters; D051745:Protein Kinase C-delta