Abstract
Mechanisms coupling the atypical PKC (aPKC) kinase activity to its subcellular localization are essential for cell polarization. Unlike other members of the PKC family, aPKC has no well-defined plasma membrane (PM) or calcium binding domains, leading to the assumption that its subcellular localization relies exclusively on protein-protein interactions. Here we show that in both Drosophila and mammalian cells, the pseudosubstrate region (PSr) of aPKC acts as a polybasic domain capable of targeting aPKC to the PM via electrostatic binding to PM PI4P and PI(4,5)P2. However, physical interaction between aPKC and Par-6 is required for the PM-targeting of aPKC, likely by allosterically exposing the PSr to bind PM. Binding of Par-6 also inhibits aPKC kinase activity, and such inhibition can be relieved through Par-6 interaction with apical polarity protein Crumbs. Our data suggest a potential mechanism in which allosteric regulation of polybasic PSr by Par-6 couples the control of both aPKC subcellular localization and spatial activation of its kinase activity.
© 2020 Dong et al.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Adaptor Proteins, Signal Transducing / chemistry
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Adaptor Proteins, Signal Transducing / genetics
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Adaptor Proteins, Signal Transducing / metabolism*
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Allosteric Regulation
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Animals
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Animals, Genetically Modified
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Cell Membrane / enzymology*
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Cell Membrane / ultrastructure
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Cell Polarity / genetics
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DNA-Binding Proteins / chemistry
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Drosophila Proteins / chemistry
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Drosophila Proteins / genetics
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Drosophila Proteins / metabolism*
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Drosophila melanogaster / cytology
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Drosophila melanogaster / enzymology*
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Drosophila melanogaster / genetics
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Embryo, Nonmammalian
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Epithelial Cells / enzymology
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Epithelial Cells / ultrastructure
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Gene Expression Regulation
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Genes, Reporter
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Green Fluorescent Proteins / genetics
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Green Fluorescent Proteins / metabolism
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HEK293 Cells
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Humans
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Larva / cytology
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Larva / enzymology
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Membrane Proteins / chemistry
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Membrane Proteins / genetics
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Membrane Proteins / metabolism*
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Phosphatidylinositol 4,5-Diphosphate / chemistry
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Phosphatidylinositol 4,5-Diphosphate / metabolism
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Phosphatidylinositol Phosphates / chemistry
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Phosphatidylinositol Phosphates / metabolism
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Protein Binding
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Protein Interaction Domains and Motifs
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Protein Kinase C / chemistry
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Protein Kinase C / genetics
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Protein Kinase C / metabolism*
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Signal Transduction
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Transcription Factors / chemistry
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Transcription Factors / genetics
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Transcription Factors / metabolism
Substances
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Adaptor Proteins, Signal Transducing
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Cyan Fluorescent Protein
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DNA-Binding Proteins
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Drosophila Proteins
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Membrane Proteins
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PARD6A protein, human
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PBRM1 protein, human
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Phosphatidylinositol 4,5-Diphosphate
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Phosphatidylinositol Phosphates
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Transcription Factors
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crb protein, Drosophila
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phosphatidylinositol 4-phosphate
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Green Fluorescent Proteins
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protein kinase C zeta
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Par-6 protein, Drosophila
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Protein Kinase C
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aPKC protein, Drosophila