Signal transduction
BMP4, as a member of the transforming growth factor-β (TGF-β) family binds to 2 different types of serine-threonine kinase receptors known as BMPR1 and BMPR2. Signal transduction via these receptors occurs via Smad and map kinase pathways to effect transcription of its target genes. In order for signal transduction to occur, both receptors must be functional. BMP is able to bind to BMPR2 without BMPR1 however, the affinity significantly increases in the presence of both receptors. BMPR1 is transphosphorylated via BMPR2 which induces downstream signalling within the cell, affecting transcription.