Formation of stable attachments between kinetochores and microtubules depends on the B56-PP2A phosphatase

Nat Cell Biol. 2011 Aug 28;13(10):1265-71. doi: 10.1038/ncb2327.

Abstract

Error-free chromosome segregation depends on the precise regulation of phosphorylation to stabilize kinetochore-microtubule attachments (K-fibres) on sister chromatids that have attached to opposite spindle poles (bi-oriented). In many instances, phosphorylation correlates with K-fibre destabilization. Consistent with this, multiple kinases, including Aurora B and Plk1, are enriched at kinetochores of mal-oriented chromosomes when compared with bi-oriented chromosomes, which have stable attachments. Paradoxically, however, these kinases also target to prometaphase chromosomes that have not yet established spindle attachments and it is therefore unclear how kinetochore-microtubule interactions can be stabilized when kinase levels are high. Here we show that the generation of stable K-fibres depends on the B56-PP2A phosphatase, which is enriched at centromeres/kinetochores of unattached chromosomes. When B56-PP2A is depleted, K-fibres are destabilized and chromosomes fail to align at the spindle equator. Strikingly, B56-PP2A depletion increases the level of phosphorylation of Aurora B and Plk1 kinetochore substrates as well as Plk1 recruitment to kinetochores. Consistent with increased substrate phosphorylation, we find that chemical inhibition of Aurora or Plk1 restores K-fibres in B56-PP2A-depleted cells. Our findings reveal that PP2A, an essential tumour suppressor, tunes the balance of phosphorylation to promote chromosome-spindle interactions during cell division.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aurora Kinase B
  • Aurora Kinases
  • Benzamides / pharmacology
  • Cell Cycle Proteins / antagonists & inhibitors
  • Cell Cycle Proteins / metabolism
  • Chromosome Segregation* / drug effects
  • HeLa Cells
  • Humans
  • Indoles / pharmacology
  • Kinetochores / drug effects
  • Kinetochores / enzymology*
  • Leupeptins / pharmacology
  • Microscopy, Fluorescence
  • Microtubules / drug effects
  • Microtubules / enzymology*
  • Nocodazole / pharmacology
  • Phosphorylation
  • Protein Kinase Inhibitors / pharmacology
  • Protein Phosphatase 2 / genetics
  • Protein Phosphatase 2 / metabolism*
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors
  • Protein-Serine-Threonine Kinases / metabolism
  • Proto-Oncogene Proteins / antagonists & inhibitors
  • Proto-Oncogene Proteins / metabolism
  • Pteridines / pharmacology
  • Quinazolines / pharmacology
  • RNA Interference
  • Recombinant Fusion Proteins / metabolism
  • Sulfonamides / pharmacology
  • Time Factors
  • Transfection
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism*

Substances

  • 4-(4-(N-benzoylamino)anilino)-6-methoxy-7-(3-(1-morpholino)propoxy)quinazoline
  • BI 2536
  • Benzamides
  • Cell Cycle Proteins
  • Indoles
  • Leupeptins
  • PPP2R5A protein, human
  • Protein Kinase Inhibitors
  • Proto-Oncogene Proteins
  • Pteridines
  • Quinazolines
  • Recombinant Fusion Proteins
  • Sulfonamides
  • Tumor Suppressor Proteins
  • AURKB protein, human
  • Aurora Kinase B
  • Aurora Kinases
  • Protein-Serine-Threonine Kinases
  • polo-like kinase 1
  • Protein Phosphatase 2
  • hesperadin
  • benzyloxycarbonylleucyl-leucyl-leucine aldehyde
  • Nocodazole