Investigating Crosstalk Between The BMP And Wnt Pathways During Drosophila Development

The need to coordinate growth and patterning in the early embryo has been appreciated for many years. This precise developmental management is believed to be achieved by individual cells receiving and deciphering the intensity of signal inputs within tissue fields. Even with our increasing understanding of these biological procecesses, much still remains to be elucidated. Indeed, there is growing evidence which demonstrates that signaling pathways do not act in isolation but in fact are constantly sensing and communicating with each other in a cellular process known as crosstalk. Our lab at California State University, Los Angeles focusses on this pertinent question of crosstalk by studying basic embryological processes during Drosophila development. Our strategy is to identify new nodes of cross-communication between two central morphogen pathways, the bone morphogentic protein (BMP) and Wingless (Wg) pathways using genetic, molecular and biochemical assays. BMP and Wg are known to regulate a diverse range of biological events, such as stem cell maintenance, cell fate specification, and organogenesis. In contrast, abnormal BMP or Wg signaling can lead to diseases such as cancer. Recently, our lab identified a new node of signal integration between the BMP and Wingless pathways. We discovered that the BMP transcription factor Smad1 is shared between the BMP or Wg pathways and its choice is dependent on its phosphorylation state. In conclusion, we present evidence that a new complexity in cell communication exists between two unrelated morphogen pathways, through component sharing and controlled by phosphorylations.