Membrane blebbing during apoptosis results from caspase-mediated activation of ROCK I

Research output: Contribution to journalArticlepeer-review


  • E A Sahai
  • M Yeo
  • M Bosch
  • A Dewar
  • M F Olson

Colleges, School and Institutes


The execution phase of apoptosis is characterized by marked changes in cell morphology that include contraction and membrane blebbing. The actin-myosin system has been proposed to be the source of contractile force that drives bleb formation, although the biochemical pathway that promotes actin-myosin contractility during apoptosis has not been identified. Here we show that the Rho effector protein ROCK I, which contributes to phosphorylation of myosin light-chains, myosin ATPase activity and coupling of actin-myosin filaments to the plasma membrane, is cleaved during apoptosis to generate a truncated active form. The activity of ROCK proteins is both necessary and sufficient for formation of membrane blebs and for re-localization of fragmented DNA into blebs and apoptotic bodies.


Original languageEnglish
Pages (from-to)339-45
Number of pages7
JournalNature Cell Biology
Issue number4
Publication statusPublished - Apr 2001


  • 3T3 Cells, Animals, Apoptosis, Caspase Inhibitors, Caspases, Cell Membrane, DNA, DNA Fragmentation, Enzyme Activation, Humans, Intracellular Signaling Peptides and Proteins, Mice, Protein-Serine-Threonine Kinases, Recombinant Fusion Proteins, Tumor Cells, Cultured, rho-Associated Kinases