title: Human Nek7-interactor RGS2 is required for mitotic spindle organization.
abstract: The mitotic spindle apparatus is composed of microtubule (MT) networks attached to kinetochores organized from 2 centrosomes (a.k.a. spindle poles). In addition to this central spindle apparatus, astral MTs assemble at the mitotic spindle pole and attach to the cell cortex to ensure appropriate spindle orientation. We propose that cell cycle-related kinase, Nek7, and its novel interacting protein RGS2, are involved in mitosis regulation and spindle formation. We found that RGS2 localizes to the mitotic spindle in a Nek7-dependent manner, and along with Nek7 contributes to spindle morphology and mitotic spindle pole integrity. RGS2-depletion leads to a mitotic-delay and severe defects in the chromosomes alignment and congression. Importantly, RGS2 or Nek7 depletion or even overexpression of wild-type or kinase-dead Nek7, reduced γ-tubulin from the mitotic spindle poles. In addition to causing a mitotic delay, RGS2 depletion induced mitotic spindle misorientation coinciding with astral MT-reduction. We propose that these phenotypes directly contribute to a failure in mitotic spindle alignment to the substratum. In conclusion, we suggest a molecular mechanism whereupon Nek7 and RGS2 may act cooperatively to ensure proper mitotic spindle organization.
authors: a Laboratório Nacional de Biociências-LNBio ; Centro Nacional de Pesquisa em Energia e Materiais-CNPEM ; Campinas , SP Brasil.
authors: Edmarcia Elisa
authors: EE
authors: de Souza
authors: Heidi
authors: H
authors: Hehnly
authors: Arina Marina
authors: AM
authors: Perez
authors: Gabriela Vaz
authors: GV
authors: Meirelles
authors: Juliana Helena Costa
authors: JH
authors: Smetana
authors: Stephen
authors: S
authors: Doxsey
authors: Jörg
authors: J
authors: Kobarg
mesh_terms: D003001:Cloning, Molecular; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008856:Microscopy, Fluorescence; D008938:Mitosis / Q000502:physiology*; D000072379:NIMA-Related Kinases; D010766:Phosphorylation; D010957:Plasmids / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D020710:RGS Proteins / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism / Q000502:physiology*; D059008:Time-Lapse Imaging; D014404:Tubulin / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D020710:RGS Proteins; C087182:RGS2 protein, human; D014404:Tubulin; C512685:NEK7 protein, human; D000072379:NIMA-Related Kinases; D017346:Protein Serine-Threonine Kinases
keywords: CREST, calcium-responsive transactivator; EB1, end-binding protein 1; GAP, GTPase-activating protein; MT, microtubule; Nek, NIMA-related kinase; Nek7; PCM, centrosomal pericentriolar material; PD, pull-down; PPI, protein-protein interaction; RGS, regulators of G protein signaling; RGS2; WB, Western blotting; cell division; mitotic spindle; mitotic spindle orientation; shRNA, short-interfering RNA