The Spindle Assembly Checkpoint Is Not Essential for Viability of Human Cells with Genetically Lowered APC/C Activity

Cell Rep. 2016 Mar 1;14(8):1829-40. doi: 10.1016/j.celrep.2016.01.060. Epub 2016 Feb 18.

Abstract

The anaphase-promoting complex/cyclosome (APC/C) and the spindle assembly checkpoint (SAC), which inhibits the APC/C, are essential determinants of mitotic timing and faithful division of genetic material. Activation of the APC/C is known to depend on two APC/C-interacting E2 ubiquitin-conjugating enzymes-UBE2C and UBE2S. We show that APC/C activity in human cells is tuned by the combinatorial use of three E2s, namely UBE2C, UBE2S, and UBE2D. Genetic deletion of UBE2C and UBE2S, individually or in combination, leads to discriminative reduction in APC/C function and sensitizes cells to UBE2D depletion. Reduction of APC/C activity results in loss of switch-like metaphase-to-anaphase transition and, strikingly, renders cells insensitive to chemical inhibition of MPS1 and genetic ablation of MAD2, both of which are essential for the SAC. These results provide insights into the regulation of APC/C activity and demonstrate that the essentiality of the SAC is imposed by the strength of the APC/C.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaphase / drug effects
  • Anaphase-Promoting Complex-Cyclosome / antagonists & inhibitors
  • Anaphase-Promoting Complex-Cyclosome / genetics*
  • Anaphase-Promoting Complex-Cyclosome / metabolism
  • CRISPR-Cas Systems
  • Cell Cycle Proteins / antagonists & inhibitors
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cell Survival / drug effects
  • Gene Deletion
  • Gene Expression
  • HCT116 Cells
  • Humans
  • M Phase Cell Cycle Checkpoints
  • Mad2 Proteins / deficiency
  • Mad2 Proteins / genetics*
  • Metaphase / drug effects
  • Morpholines / pharmacology
  • Nocodazole / pharmacology
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism
  • Protein-Tyrosine Kinases / antagonists & inhibitors
  • Protein-Tyrosine Kinases / genetics
  • Protein-Tyrosine Kinases / metabolism
  • Purines / pharmacology
  • Signal Transduction
  • Spindle Apparatus / drug effects
  • Spindle Apparatus / metabolism*
  • Spindle Apparatus / ultrastructure
  • Ubiquitin-Conjugating Enzymes / deficiency
  • Ubiquitin-Conjugating Enzymes / genetics*
  • Ubiquitin-Conjugating Enzymes / metabolism

Substances

  • Cell Cycle Proteins
  • MAD2L1 protein, human
  • Mad2 Proteins
  • Morpholines
  • Purines
  • UBE2C protein, human
  • UBE2D1 protein, human
  • Ube2S protein, human
  • Ubiquitin-Conjugating Enzymes
  • Anaphase-Promoting Complex-Cyclosome
  • Protein-Tyrosine Kinases
  • Protein-Serine-Threonine Kinases
  • TTK protein, human
  • Nocodazole
  • 2-(4-morpholinoanilino)-6-cyclohexylaminopurine