Receptor-interacting Ser/Thr kinase 1 (RIPK1) and myosin IIA-dependent ceramidosomes form membrane pores that mediate blebbing and necroptosis

J Biol Chem. 2019 Jan 11;294(2):502-519. doi: 10.1074/jbc.RA118.005865. Epub 2018 Nov 12.


Formation of membrane pores/channels regulates various cellular processes, such as necroptosis or stem cell niche signaling. However, the roles of membrane lipids in the formation of pores and their biological functions are largely unknown. Here, using the cellular stress model evoked by the sphingolipid analog drug FTY720, we show that formation of ceramide-enriched membrane pores, referred to here as ceramidosomes, is initiated by a receptor-interacting Ser/Thr kinase 1 (RIPK1)-ceramide complex transported to the plasma membrane by nonmuscle myosin IIA-dependent trafficking in human lung cancer cells. Molecular modeling/simulation coupled with site-directed mutagenesis revealed that Asp147 or Asn169 of RIPK1 are key for ceramide binding and that Arg258 or Leu293 residues are involved in the myosin IIA interaction, leading to ceramidosome formation and necroptosis. Moreover, generation of ceramidosomes independently of any external drug/stress stimuli was also detected in the plasma membrane of germ line stem cells in ovaries during the early stages of oogenesis in Drosophila melanogaster Inhibition of ceramidosome formation via myosin IIA silencing limited germ line stem cell signaling and abrogated oogenesis. In conclusion, our findings indicate that the RIPK1-ceramide complex forms large membrane pores we named ceramidosomes. They further suggest that, in addition to their roles in stress-mediated necroptosis, these ceramide-enriched pores also regulate membrane integrity and signaling and might also play a role in D. melanogaster ovary development.

Keywords: FTY720; RIPK1; ceramide; ceramide-enriched membrane pores; ceramidosome; lipid binding protein; membrane lipid; myosin; necrosis (necrotic death); sphingolipid.

Publication types

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

MeSH terms

  • A549 Cells
  • Animals
  • Cell Line
  • Cell Membrane / metabolism*
  • Cell Membrane / pathology
  • Ceramides / metabolism*
  • Drosophila melanogaster / growth & development
  • Female
  • Humans
  • Lung Neoplasms / metabolism*
  • Lung Neoplasms / pathology
  • Molecular Docking Simulation
  • Molecular Motor Proteins / metabolism*
  • Myosin Heavy Chains / metabolism*
  • Necrosis / metabolism*
  • Necrosis / pathology
  • Oogenesis
  • Ovary / growth & development
  • Receptor-Interacting Protein Serine-Threonine Kinases / metabolism*


  • Ceramides
  • MYH9 protein, human
  • Molecular Motor Proteins
  • RIPK1 protein, human
  • Receptor-Interacting Protein Serine-Threonine Kinases
  • Myosin Heavy Chains

Associated data

  • PDB/4NEU
  • PDB/5HX6
  • PDB/3L82
  • PDB/4KP3