title: Meiotic maturation induces animal-vegetal asymmetric distribution of aPKC and ASIP/PAR-3 in Xenopus oocytes.
abstract: The asymmetric distribution of cellular components is an important clue for understanding cell fate decision during embryonic patterning and cell functioning after differentiation. In C. elegans embryos, PAR-3 and aPKC form a complex that colocalizes to the anterior periphery of the one-cell embryo, and are indispensable for anterior-posterior polarity that is formed prior to asymmetric cell division. In mammals, ASIP (PAR-3 homologue) and aPKCgamma form a complex and colocalize to the epithelial tight junctions, which play critical roles in epithelial cell polarity. Although the mechanism by which PAR-3/ASIP and aPKC regulate cell polarization remains to be clarified, evolutionary conservation of the PAR-3/ASIP-aPKC complex suggests their general role in cell polarity organization. Here, we show the presence of the protein complex in Xenopus laevis. In epithelial cells, XASIP and XaPKC colocalize to the cell-cell contact region. To our surprise, they also colocalize to the animal hemisphere of mature oocytes, whereas they localize uniformly in immature oocytes. Moreover, hormonal stimulation of immature oocytes results in a change in the distribution of XaPKC 2-3 hours after the completion of germinal vesicle breakdown, which requires the kinase activity of aPKC. These results suggest that meiotic maturation induces the animal-vegetal asymmetry of aPKC.
authors.affiliation: Department of Molecular Biology, Yokohama City University School of Medicine, Yokohama 236-0004, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Nakaya
authors.forename: A
authors.initials: A
authors.lastname: Fukui
authors.forename: Y
authors.initials: Y
authors.lastname: Izumi
authors.forename: K
authors.initials: K
authors.lastname: Akimoto
authors.forename: M
authors.initials: M
authors.lastname: Asashima
authors.forename: S
authors.initials: S
authors.lastname: Ohno
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D020134:Catalytic Domain; D015815:Cell Adhesion Molecules; D018797:Cell Cycle Proteins; D016764:Cell Polarity / Q000502:physiology*; D004847:Epithelial Cells / Q000378:metabolism / Q000502:physiology; D005306:Fertilization; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000276:immunology / Q000378:metabolism; D008540:Meiosis / Q000502:physiology*; D051379:Mice; D009865:Oocytes / Q000378:metabolism; D010063:Ovum / Q000378:metabolism / Q000502:physiology; D011493:Protein Kinase C / Q000276:immunology / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D014982:Xenopus laevis / Q000196:embryology; D000099293:Protein Kinase C-lambda; D000099221:Protein Kinase C zeta
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D015815:Cell Adhesion Molecules; D018797:Cell Cycle Proteins; D015801:Helminth Proteins; D007527:Isoenzymes; D011493:Protein Kinase C; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger; D000099293:Protein Kinase C-lambda; D000099221:Protein Kinase C zeta; C115084:Pard3 protein, mouse; C097238:PAR-3 protein, C elegans; C115015:PKC-3 protein