Interpretation of a BMP activity gradient in Drosophila embryos depends on synergistic signaling by two type I receptors, SAX and TKV

Cell. 1998 Nov 13;95(4):495-506. doi: 10.1016/s0092-8674(00)81617-7.


Graded activity of the DPP signaling pathway is critical for specification of dorsal embryonic cell fates in Drosophila. We present evidence that a second BMP ligand, SCW, potentiates DPP activity. Using dominant-negative forms of the type I receptors SAX and TKV, we demonstrate that SAX mediates the SCW signal, while TKV is required for both DPP and SCW activity. We find that while DPP/TKV signaling is obligatorily required, SCW/SAX activity is necessary but not sufficient for dorsal patterning. SAX and TKV act synergistically, suggesting a mechanism for integration of the SCW and DPP signals. Further, we show that the extracellular protein SOG can antagonize SCW, thus limiting its ability to augment DPP signaling in a graded manner.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Body Patterning / physiology
  • Bone Morphogenetic Proteins / metabolism
  • Bone Morphogenetic Proteins / physiology*
  • Dimerization
  • Drosophila / embryology*
  • Drosophila Proteins*
  • Drug Synergism
  • Insect Proteins / physiology
  • Ligands
  • Protein-Serine-Threonine Kinases / physiology*
  • Receptors, Cell Surface / physiology*
  • Receptors, Transforming Growth Factor beta / physiology*
  • Signal Transduction / physiology*
  • Transforming Growth Factor beta / metabolism
  • Transforming Growth Factor beta / physiology*


  • Bone Morphogenetic Proteins
  • Drosophila Proteins
  • Insect Proteins
  • Ligands
  • Receptors, Cell Surface
  • Receptors, Transforming Growth Factor beta
  • SCW protein, Drosophila
  • Transforming Growth Factor beta
  • dpp protein, Drosophila
  • sax protein, Drosophila
  • sog protein, Drosophila
  • tkv protein, Drosophila
  • Protein-Serine-Threonine Kinases