The intensity and duration of activation of a signal transduction system are important
determinants of the specificity of the cellular response to the stimulus. It is unclear how
different cells can generate a signal of varying intensity and duration in response to the
same cytokine. We investigated the role of the transcriptional activator and Smad1/4 cofactor
OAZ in regulating bone morphogenetic protein (BMP) signaling. We demonstrate that upon
BMP4 stimulation, an OAZ-Smad1/4 complex binds to and activates the gene encoding …