The Drosophila PAR-1 spacer domain is required for lateral membrane association and for polarization of follicular epithelial cells.
The Ser/Thr kinases of the PAR-1/MARK/Kin1 family are conserved regulators of polarity in epithelial and non-epithelial cells . Drosophila PAR-1 localizes laterally in the follicular epithelium of the ovary , where it has been shown to function at two distinct levels: It stabilizes the cytoskeleton and it regulates apical-basal polarity by directly inhibiting lateral assembly of the apical aPKC/Bazooka/PAR-6 complex . However, it has been unclear how lateral localization of Drosophila PAR-1 is achieved and whether this localization contributes to epithelial polarity in vivo. Here we show that, through its spacer domain, Drosophila PAR-1 accumulates on the lateral plasma membrane (PM) in cells of the follicular epithelium (FE). Rescue experiments indicate that in FE cells PAR-1 kinase activity is essential for all the described functions of PAR-1. In contrast, the spacer domain of PAR-1 is required for apical-basal polarity and growth control but is dispensable for microtubule (MT) stabilization. Our data indicate that the spacer domain of PAR-1 is required for lateral PM localization of PAR-1 kinase and for development of a polarized FE.
Vaccari
Thomas
T
Developmental Biology Programme, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
Rabouille
Catherine
C
Ephrussi
Anne
A
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity / Q000235:genetics*; D002478:Cells, Cultured; D017931:DNA Primers; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics*; D004848:Epithelium / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D005455:Fluorescent Antibody Technique; D038362:Glycogen Synthase Kinase 3; D049452:Green Fluorescent Proteins; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D006080:Ovarian Follicle / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D019076:Transgenes / Q000235:genetics
D017931:DNA Primers; D029721:Drosophila Proteins; D049452:Green Fluorescent Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D038362:Glycogen Synthase Kinase 3; C472496:Par-1 protein, Drosophila