title: The conformation and activation of Fyn kinase in the oocyte determine its localisation to the spindle poles and cleavage furrow.
abstract: Several lines of evidence imply the involvement of Fyn, a Src family kinase, in cell-cycle control and cytoskeleton organisation in somatic cells. By live cell confocal imaging of immunostained or cRNA-microinjected mouse oocytes at metaphase of the second meiotic division, membrane localisation of active and non-active Fyn was demonstrated. However, Fyn with a disrupted membrane-binding domain at its N-terminus was targeted to the cytoplasm and spindle in its non-active form and concentrated at the spindle poles when active. During metaphase exit, the amount of phosphorylated Fyn and of spindle-poles Fyn decreased and it started appearing at the membrane area of the cleavage furrow surrounding the spindle midzone, either asymmetrically during polar body II extrusion or symmetrically during mitosis. These results demonstrate that post-translational modifications of Fyn, probably palmitoylation, determine its localisation and function; localisation of de-palmitoylated active Fyn to the spindle poles is involved in spindle pole integrity during metaphase, whereas the localisation of N-terminus palmitoylated Fyn at the membrane near the cleavage furrow indicates its participation in furrow ingression during cytokinesis.
authors.affiliation: Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel-Aviv, Israel.
authors.forename: Mattan
authors.initials: M
authors.lastname: Levi
authors.forename: Bernard
authors.initials: B
authors.lastname: Maro
authors.forename: Ruth
authors.initials: R
authors.lastname: Shalgi
mesh_terms: D000818:Animals; D021461:Animals, Outbred Strains; D002453:Cell Cycle; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D048749:Cytokinesis; D004789:Enzyme Activation; D005260:Female; D020868:Gene Silencing; D008540:Meiosis; D008677:Metaphase; D051379:Mice; D008813:Mice, Inbred ICR; D050505:Mutant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D033661:Oocysts / Q000502:physiology* / Q000648:ultrastructure*; D010766:Phosphorylation; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D051076:Proto-Oncogene Proteins c-fyn / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018075:RNA, Complementary; D008941:Spindle Apparatus / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D050505:Mutant Proteins; D018075:RNA, Complementary; C494960:Fyn protein, mouse; D051076:Proto-Oncogene Proteins c-fyn