The apical determinants aPKC and dPatj regulate Frizzled-dependent planar cell polarity in the Drosophila eye.
Planar cell polarity (PCP) is a common feature of many vertebrate and invertebrate epithelia and is perpendicular to their apical/basal (A/B) polarity axis. While apical localization of PCP determinants such as Frizzled (Fz1) is critical for their function, the link between A/B polarity and PCP is poorly understood. Here, we describe a direct molecular link between A/B determinants and Fz1-mediated PCP establishment in the Drosophila eye. We demonstrate that dPatj binds the cytoplasmic tail of Fz1 and propose that it recruits aPKC, which in turn phosphorylates and inhibits Fz1. Accordingly, components of the aPKC complex and dPatj produce PCP defects in the eye. We also show that during PCP signaling, aPKC and dPatj are downregulated, while Bazooka is upregulated, suggesting an antagonistic effect of Bazooka on dPatj/aPKC. We propose a model whereby the dPatj/aPKC complex regulates PCP by inhibiting Fz1 in cells where it should not be active.
Djiane
Alexandre
A
Brookdale Department of Molecular, Cell and Developmental Biology, Mount Sinai School of Medicine, New York, New York 10029.
Yogev
Shaul
S
Brookdale Department of Molecular, Cell and Developmental Biology, Mount Sinai School of Medicine, New York, New York 10029.
Mlodzik
Marek
M
Brookdale Department of Molecular, Cell and Developmental Biology, Mount Sinai School of Medicine, New York, New York 10029. Electronic address: marek.mlodzik@mssm.edu.
D000818:Animals; D001665:Binding Sites / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity / Q000235:genetics*; D015536:Down-Regulation / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000378:metabolism / Q000648:ultrastructure; D004847:Epithelial Cells / Q000378:metabolism* / Q000648:ultrastructure; D005123:Eye / Q000196:embryology* / Q000378:metabolism / Q000648:ultrastructure; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism*; D051157:Frizzled Receptors; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D017956:Photoreceptor Cells, Invertebrate / Q000196:embryology / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D011493:Protein Kinase C / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled; D062725:Tight Junction Proteins; D015854:Up-Regulation / Q000502:physiology
D029721:Drosophila Proteins; D005136:Eye Proteins; D051157:Frizzled Receptors; D047908:Intracellular Signaling Peptides and Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; C501446:PATJ protein, Drosophila; C107903:PATJ protein, human; D043562:Receptors, G-Protein-Coupled; D062725:Tight Junction Proteins; C400774:baz protein, Drosophila; C064360:crb protein, Drosophila; C058784:fz protein, Drosophila; C115015:PKC-3 protein; D011493:Protein Kinase C