Developmental pattern of expression of BMP receptors and Smads and activation of Smad1 and Smad5 by BMP9 in mouse basal forebrain.

Basal forebrain cholinergic neurons play critical roles in the organization of brain cortical structures and in processes such as learning and memory. We have previously shown that bone morphogenetic protein (BMP) 9, a member of the transforming growth factor (TGF) beta superfamily of cytokines, is a differentiating factor for cholinergic central nervous system neurons. However, whereas the basic signal transduction pathways for most known members of the TGF-beta superfamily have been well characterized in brain and other organs, nothing is known about the signal transduction pathway of BMP9 in the brain.