Actin-myosin-based contraction is responsible for apoptotic nuclear disintegration

Daniel R Croft, Mathew L Coleman, Shuixing Li, David Robertson, Teresa Sullivan, Colin L Stewart, Michael F Olson

Research output: Contribution to journalArticlepeer-review

153 Citations (Scopus)


Membrane blebbing during the apoptotic execution phase results from caspase-mediated cleavage and activation of ROCK I. Here, we show that ROCK activity, myosin light chain (MLC) phosphorylation, MLC ATPase activity, and an intact actin cytoskeleton, but not microtubular cytoskeleton, are required for disruption of nuclear integrity during apoptosis. Inhibition of ROCK or MLC ATPase activity, which protect apoptotic nuclear integrity, does not affect caspase-mediated degradation of nuclear proteins such as lamins A, B1, or C. The conditional activation of ROCK I was sufficient to tear apart nuclei in lamin A/C null fibroblasts, but not in wild-type fibroblasts. Thus, apoptotic nuclear disintegration requires actin-myosin contractile force and lamin proteolysis, making apoptosis analogous to, but distinct from, mitosis where nuclear disintegration results from microtubule-based forces and from lamin phosphorylation and depolymerization.

Original languageEnglish
Pages (from-to)245-55
Number of pages11
JournalJournal of Cell Biology
Issue number2
Publication statusPublished - 17 Jan 2005


  • Actins
  • Amides
  • Animals
  • Apoptosis
  • Caspase Inhibitors
  • Caspases
  • Cell Nucleus
  • Cycloheximide
  • Cytochalasin D
  • Cytoskeletal Proteins
  • Cytoskeleton
  • Enzyme Inhibitors
  • Fibroblasts
  • Intracellular Signaling Peptides and Proteins
  • Lamins
  • Lim Kinases
  • Mice
  • Microscopy, Electron, Transmission
  • Microtubules
  • Mutation
  • Myosin Light Chains
  • Myosin-Light-Chain Phosphatase
  • Myosins
  • NIH 3T3 Cells
  • Nocodazole
  • Nuclear Lamina
  • Nuclear Proteins
  • Phosphoproteins
  • Phosphorylation
  • Protein Kinases
  • Protein-Serine-Threonine Kinases
  • Pyridines
  • Transfection
  • Tumor Necrosis Factor-alpha
  • rho-Associated Kinases


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