BMPs initiate their signaling cascade by binding to specific cell surface receptors known as BMP receptors (BMPRs), which are serine/threonine kinase receptors. Upon ligand binding, these receptors phosphorylate and activate intracellular SMAD proteins. The activated SMADs translocate to the nucleus, where they modulate the transcription of target genes involved in cell proliferation, differentiation, and apoptosis.
