Transcriptional modulator activated by BMP (bone morphogenetic proteins) type 1 receptor kinase. SMAD9 is a receptor-regulated SMAD (R-SMAD).
Subcellular locations: Cytoplasm, Nucleus
In the cytoplasm in the absence of ligand. Migration to the nucleus when complexed with SMAD4 (By similarity).
Expressed in heart, brain, placenta, lung, skeletal muscle, prostate, testis, ovary and small intestine. Also expressed in fetal brain, lung and kidney.