title: The GCP3-interacting proteins GIP1 and GIP2 are required for γ-tubulin complex protein localization, spindle integrity, and chromosomal stability.
abstract: Microtubules (MTs) are crucial for both the establishment of cellular polarity and the progression of all mitotic phases leading to karyokinesis and cytokinesis. MT organization and spindle formation rely on the activity of γ-tubulin and associated proteins throughout the cell cycle. To date, the molecular mechanisms modulating γ-tubulin complex location remain largely unknown. In this work, two Arabidopsis thaliana proteins interacting with gamma-tubulin complex protein3 (GCP3), GCP3-interacting protein1 (GIP1) and GIP2, have been characterized. Both GIP genes are ubiquitously expressed in all tissues analyzed. Immunolocalization studies combined with the expression of GIP-green fluorescent protein fusions have shown that GIPs colocalize with γ-tubulin, GCP3, and/or GCP4 and reorganize from the nucleus to the prospindle and the preprophase band in late G2. After nuclear envelope breakdown, they localize on spindle and phragmoplast MTs and on the reforming nuclear envelope of daughter cells. The gip1 gip2 double mutants exhibit severe growth defects and sterility. At the cellular level, they are characterized by MT misorganization and abnormal spindle polarity, resulting in ploidy defects. Altogether, our data show that during mitosis GIPs play a role in γ-tubulin complex localization, spindle stability and chromosomal segregation.
authors.affiliation: Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Unité Propre de Recherche 2357, Conventioné avec l'Université de Strasbourg, 67084 Strasbourg, France.
authors.forename: Natacha
authors.initials: N
authors.lastname: Janski
authors.forename: Kinda
authors.initials: K
authors.lastname: Masoud
authors.forename: Morgane
authors.initials: M
authors.lastname: Batzenschlager
authors.forename: Etienne
authors.initials: E
authors.lastname: Herzog
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Evrard
authors.forename: Guy
authors.initials: G
authors.lastname: Houlné
authors.forename: Mickael
authors.initials: M
authors.lastname: Bourge
authors.forename: Marie-Edith
authors.initials: ME
authors.lastname: Chabouté
authors.forename: Anne-Catherine
authors.initials: AC
authors.lastname: Schmit
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D043171:Chromosomal Instability; D004269:DNA, Bacterial / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008938:Mitosis; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D008941:Spindle Apparatus / Q000378:metabolism*; D014404:Tubulin / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; C530431:GCP3 protein, Arabidopsis; C509716:GIP1 protein, Arabidopsis; D008869:Microtubule-Associated Proteins; C036483:T-DNA; D014404:Tubulin