The assembly of POSH-JNK regulates Xenopus anterior neural development

Dev Biol. 2005 Oct 1;286(1):256-69. doi: 10.1016/j.ydbio.2005.07.033.


POSH (Plenty of SH3s) has distinct roles as a scaffold for specific c-Jun N-terminal kinase (JNK) signaling modules and as an E3 ubiquitin ligase. The physiological function of POSH remains unclear, however, and its possible involvement in developmental processes motivated the present study wherein the Xenopus orthologue of POSH (xPOSH) was examined for its potential role during Xenopus early embryogenesis. Loss-of-function analysis using morpholino oligonucleotides demonstrated that POSH was essential for Xenopus anterior neural development, although not Spemann organizer formation and early neurogenesis, through the formation of an active JNK signaling complex. Moreover, POSH-mediated JNK pathway was essential for apoptosis in anterior neural tissues. Finally, the present findings demonstrate that RING (Really Interesting New Gene) domain-mediated E3 ubiquitin ligase activity of POSH was not involved in POSH-mediated JNK pathway in vivo. Together, these data suggest that the active JNK signaling complex formed of POSH and the JNK module is essential for the expression of anterior neural genes and apoptosis in Xenopus anterior development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / chemistry
  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Animals
  • Apoptosis
  • Base Sequence
  • Cell Line
  • DNA, Antisense / genetics
  • Gene Expression Regulation, Developmental
  • Gene Targeting
  • Humans
  • JNK Mitogen-Activated Protein Kinases / chemistry
  • JNK Mitogen-Activated Protein Kinases / genetics
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Multiprotein Complexes
  • Nervous System / cytology
  • Nervous System / embryology*
  • Nervous System / metabolism*
  • Signal Transduction
  • Transfection
  • Xenopus laevis / embryology*
  • Xenopus laevis / genetics
  • Xenopus laevis / metabolism*
  • src Homology Domains


  • Adaptor Proteins, Signal Transducing
  • DNA, Antisense
  • Multiprotein Complexes
  • JNK Mitogen-Activated Protein Kinases