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The very C-terminus of protein kinase CĹ is critical for the full catalytic competence but its hydrophobic motif is dispensable for the interaction with 3-phosphoinositide-dependent kinase-1
journal contribution
posted on 2006-06-01, 00:00 authored by Y Zhu, D Smith, C Verma, W Lim, B Tan, J Armstrong, S Zhou, E Chan, S L Tan, Y Z Zhu, Steve Cheung, Wei DuanWei DuanIn this article, we explore the role of the C-terminus (V5 domain) of PKCvar epsilon plays in the catalytic competence of the kinase using serial truncations followed by immune-complex kinase assays. Surprisingly, removal of the last seven amino acid residues at the C-terminus of PKCvar epsilon resulted in a PKCvar epsilon-Δ731 mutant with greatly reduced intrinsic catalytic activity while truncation of eight amino acid residues at the C-terminus resulted in a catalytically inactive PKCvar epsilon mutant. Computer modeling and molecular dynamics simulations showed that the last seven and/or eight amino acid residues of PKCvar epsilon were involved in interactions with residues in the catalytic core. Further truncation analyses revealed that the hydrophobic phosphorylation motif was dispensable for the physical interaction between PKCvar epsilon and 3-phosphoinositide-dependent kinase-1 (PDK-1) as the PKCvar epsilon mutant lacking both the turn and the hydrophobic motifs could still be co-immunoprecipitated with PDK-1. These results provide fresh insights into the biochemical and structural basis underlying the isozyme-specific regulation of PKC and suggest that the very C-termini of PKCs constitute a promising new target for the development of novel isozyme-specific inhibitors of PKC.
History
Journal
Cellular signallingVolume
18Issue
6Pagination
807 - 818Publisher
Elsvier Inc.Location
Amsterdam, NetherlandsPublisher DOI
ISSN
0898-6568eISSN
1873-3913Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2005, Elsevier Inc.Usage metrics
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