title: The tumor suppressor Lgl1 forms discrete complexes with NMII-A and Par6α-aPKCζ that are affected by Lgl1 phosphorylation.
abstract: Non-muscle myosin IIA (NMII-A) and the tumor suppressor lethal giant larvae 1 (Lgl1) play a central role in the polarization of migrating cells. Mammalian Lgl1 interacts directly with NMII-A, inhibiting its ability to assemble into filaments in vitro. Lgl1 also regulates the cellular localization of NMII-A, the maturation of focal adhesions and cell migration. In Drosophila, phosphorylation of Lgl affects its association with the cytoskeleton. Here we show that phosphorylation of mammalian Lgl1 by aPKCζ prevents its interaction with NMII-A both in vitro and in vivo, and affects its inhibition of NMII-A filament assembly. Phosphorylation of Lgl1 affects its cellular localization and is important for the cellular organization of the acto-NMII cytoskeleton. We further show that Lgl1 forms two distinct complexes in vivo, Lgl1-NMIIA and Lgl1-Par6α-aPKCζ, and that the formation of these complexes is affected by the phosphorylation state of Lgl1. The complex Lgl1-Par6α-aPKCζ resides in the leading edge of the cell. Finally, we show that aPKCζ and NMII-A compete to bind directly to Lgl1 at the same domain. These results provide new insights into the mechanism regulating the interaction between Lgl1, NMII-A, Par6α and aPKCζ in polarized migrating cells.
authors.affiliation: Department of Biochemistry and Molecular Biology, The Institute of Medical Research Israel-Canada, The Hebrew University - Hadassah Medical School, Jerusalem 91120, Israel.
authors.forename: Inbal
authors.initials: I
authors.lastname: Dahan
authors.forename: Daria
authors.initials: D
authors.lastname: Petrov
authors.forename: Einav
authors.initials: E
authors.lastname: Cohen-Kfir
authors.forename: Shoshana
authors.initials: S
authors.lastname: Ravid
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D003599:Cytoskeleton / Q000378:metabolism; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D008954:Models, Biological; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D041681:NIH 3T3 Cells; D024507:Nonmuscle Myosin Type IIA / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011554:Pseudopodia / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D006023:Glycoproteins; C524369:LGL1 protein, mouse; D050505:Mutant Proteins; C518597:Par6 protein, mouse; D025521:Tumor Suppressor Proteins; D049452:Green Fluorescent Proteins; C115015:PKC-3 protein; D011493:Protein Kinase C; D024507:Nonmuscle Myosin Type IIA
keywords: Cell motility; Lethal giant larvae (Lgl); Non-muscle myosin