Lgl and its phosphorylation by aPKC regulate oocyte polarity formation in Drosophila.
Specification of the anteroposterior (AP) axis in Drosophila oocytes requires proper organization of the microtubule and actin cytoskeleton. The establishment and regulation of cytoskeletal polarity remain poorly understood, however. Here, we show important roles for the tumor suppressor Lethal (2) giant larvae (Lgl) and atypical protein kinase C (aPKC) in regulating microtubule polarity and setting up the AP axis of the oocyte. Lgl in the germline cells regulates the localization of axis-specifying morphogens. aPKC phosphorylation of Lgl restricts Lgl activity to the oocyte posterior, thereby dividing the cortex into different domains along the AP axis. Active Lgl promotes the formation of actin-rich projections at the oocyte cortex and the posterior enrichment of the serine/threonine kinase Par-1, a key step for oocyte polarization. Our studies suggest that Lgl and its phosphorylation by aPKC may form a conserved regulatory circuitry in polarization of various cell types.
Tian
Ai-Guo
AG
Department of Biological Science, Florida State University, Tallahassee, FL 32306-4370, USA.
Deng
Wu-Min
WM
D000199:Actins / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation; D019070:Cell Lineage; D016764:Cell Polarity; D002999:Clone Cells; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000201:enzymology*; D038362:Glycogen Synthase Kinase 3; D009865:Oocytes / Q000166:cytology* / Q000201:enzymology*; D010766:Phosphorylation; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D021381:Protein Transport; D025521:Tumor Suppressor Proteins / Q000378:metabolism*
D000199:Actins; D029721:Drosophila Proteins; D025521:Tumor Suppressor Proteins; C081435:l(2)gl protein, Drosophila; D017346:Protein Serine-Threonine Kinases; C115015:PKC-3 protein; D011493:Protein Kinase C; D038362:Glycogen Synthase Kinase 3; C472496:Par-1 protein, Drosophila