title: Formation of ternary complex of human biliverdin reductase-protein kinase Cδ-ERK2 protein is essential for ERK2-mediated activation of Elk1 protein, nuclear factor-κB, and inducible nitric-oxidase synthase (iNOS).
abstract: Growth factors, insulin, oxidative stress, and cytokines activate ERK1/2 by PKCδ and MEK1/2. Human biliverdin reductase (hBVR), a Ser/Thr/Tyr kinase and intracellular scaffold/bridge/anchor, is a nuclear transporter of MEK1/2-stimulated ERK1/2 (Lerner-Marmarosh, N., Miralem, T., Gibbs, P. E., and Maines, M. D. (2008) Proc. Natl. Acad. Sci. U.S.A. 105, 6870-6875). hBVR, PKCδ, and MEK1/2 overlap in their tissue expression profile and type of activators. Presently, we report on formation of an hBVR-PKCδ-ERK2 ternary complex that is essential for ERK2 signal transduction and activation of genes linked to cell proliferation and cancer. MEK1/2 and the protein phosphatase PP2A were also present in the complex. When cells were stimulated with insulin-like growth factor-1 (IGF-1), an increased interaction between hBVR and PKCδ was detected by FRET-fluorescence lifetime imaging microscopy. hBVR and ERK2 were phosphorylated by PKCδ; however, the PKC was not a substrate for either ERK2 or hBVR. IGF-1 and phorbol ester increased hBVR/PKCδ binding; hBVR was required for the activation of PKCδ and its interaction with ERK2. The C-terminal phenylalanine residues of PKCδ (Phe(660), Phe(663), and Phe(665)) were necessary for binding to ERK2 but not for hBVR binding. Formation of the hBVR-PKCδ-ERK2 complex required the hBVR docking site for ERK, FXFP (DEF, C-box) and D(δ)-box (ILXXLXL) motifs. The hBVR-based peptide KKRILHCLGLA inhibited PKC activation and PKCδ/ERK2 interaction. Phorbol ester- and TNF-α-dependent activation of the ERK-regulated transcription factors Elk1 and NF-κB and expression of the iNOS gene were suppressed by hBVR siRNA; those activities were rescued by hBVR. The findings reveal the direct input of hBVR in PKCδ/ERK signaling and identify hBVR-based peptide regulators of ERK-mediated gene activation.
authors: Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
authors: Peter E M
authors: PE
authors: Gibbs
authors: Tihomir
authors: T
authors: Miralem
authors: Nicole
authors: N
authors: Lerner-Marmarosh
authors: Cicerone
authors: C
authors: Tudor
authors: Mahin D
authors: MD
authors: Maines
mesh_terms: D020816:Amino Acid Motifs; D004789:Enzyme Activation / Q000187:drug effects; D057809:HEK293 Cells; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism*; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics / Q000378:metabolism*; D010455:Peptides / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D011485:Protein Binding; D051745:Protein Kinase C-delta / Q000235:genetics / Q000378:metabolism*; D020836:Protein Structure, Quaternary; D050807:ets-Domain Protein Elk-1 / Q000235:genetics / Q000378:metabolism*
chemical_list: C494112:ELK1 protein, human; D009097:Multienzyme Complexes; D016328:NF-kappa B; D010455:Peptides; D050807:ets-Domain Protein Elk-1; D007334:Insulin-Like Growth Factor I; C496319:NOS2 protein, human; D052247:Nitric Oxide Synthase Type II; D044925:Oxidoreductases Acting on CH-CH Group Donors; C019789:biliverdin reductase; D051745:Protein Kinase C-delta; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1