Spindly/CCDC99 is required for efficient chromosome congression and mitotic checkpoint regulation.
Spindly recruits a fraction of cytoplasmic dynein to kinetochores for poleward movement of chromosomes and control of mitotic checkpoint signaling. Here we show that human Spindly is a cell cycle-regulated mitotic phosphoprotein that interacts with the Rod/ZW10/Zwilch (RZZ) complex. The kinetochore levels of Spindly are regulated by microtubule attachment and biorientation induced tension. Deletion mutants lacking the N-terminal half of the protein (NDelta253), or the conserved Spindly box (DeltaSB), strongly localized to kinetochores and failed to respond to attachment or tension. In addition, these mutants prevented the removal of the RZZ complex and that of MAD2 from bioriented chromosomes and caused cells to arrest at metaphase, showing that RZZ-Spindly has to be removed from kinetochores to terminate mitotic checkpoint signaling. Depletion of Spindly by RNAi, however, caused cells to arrest in prometaphase because of a delay in microtubule attachment. Surprisingly, this defect was alleviated by codepletion of ZW10. Thus, Spindly is not only required for kinetochore localization of dynein but is a functional component of a mechanism that couples dynein-dependent poleward movement of chromosomes to their efficient attachment to microtubules.
Barisic
Marin
M
Division of Molecular Pathophysiology, Biocenter, Innsbruck Medical University, 6020 Innsbruck, Austria.
Sohm
Bénédicte
B
Mikolcevic
Petra
P
Wandke
Cornelia
C
Rauch
Veronika
V
Ringer
Thomas
T
Hess
Michael
M
Bonn
Günther
G
Geley
Stephan
S
D002135:Calcium-Binding Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D016764:Cell Polarity; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D023902:Chromosome Pairing; D002877:Chromosomes, Human / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D005799:Genes, Dominant / Q000235:genetics; D006801:Humans; D018386:Kinetochores / Q000378:metabolism; D064246:Mad2 Proteins; D008677:Metaphase; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis; D046912:Multiprotein Complexes / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D034622:RNA Interference; D012097:Repressor Proteins / Q000378:metabolism
D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; C577697:MAD2L1 protein, human; D064246:Mad2 Proteins; D008869:Microtubule-Associated Proteins; D046912:Multiprotein Complexes; D010750:Phosphoproteins; D012097:Repressor Proteins; C549402:SPDL1 protein, human; C488261:ZW10 protein, human; D010768:Phosphoserine