Bongwater follows the story of a drug dealer.
SMADs are intracellular proteins that transduce extracellular signals from transforming growth factor beta ligands to the nucleus where they activate downstream gene transcription .. transforming growth factor beta. transforming growth factor beta. ligands. ligands. The SMADs , which form a trimer of two receptor-regulated SMADs and one co-SMAD , act as transcription factors that regulate the expression of certain genes .. trimer. Protein trimer. transcription factors. transcription factors