Despite the significant progress, the precise mechanism(s) by which BMPs regulate lung development have not been fully delineated [5] . Moreover, characterization of the mechanisms by which BMPs affect adult lung homeostasis and tissue repair is still rudimentary. The current study was based on the premise that identification of the actual cellular targets of BMP mediated signaling during lung development, homeostasis and adult lung tissue repair will facilitate interpretation of earlier genetic studies, guide rational targeting of BMP signaling components in future experiments and contribute to the clarification of the mechanisms of action of this signaling system. Therefore, utilizing a mouse transgenic line carrying the eGFP reporter gene under the control of a canonical BMP pathway responsive regulatory element [33] we have constructed a detailed spatiotemporal map of canonical BMP signaling in the lung and identified putative cellular targets of this signaling pathway during lung development and adult lung tissue-injury repair. Our studies suggest that canonical BMP pathway plays key roles during early development of the pulmonary vasculature and the management of lung epithelial cell progenitors during late lung development and repair of adult lung tissue injury.