. BMP Signaling Regulates Stem Cell Self-Renewal and/or Differentiation in Adult Niches

. The BMP signaling pathway regulates various biological processes such as cell differentiation, embryonic patterning, tissue homeostasis, and embryonic development. The pathway is initiated when a BMP ligand binds to a receptor on the cell membrane. This triggers an intracellular cascade which includes Smad proteins, a family of intracellular signaling molecules which transmit signals from the cell membrane to the nucleus. These signals control gene transcription to alter cellular behavior. Recent studies have demonstrated that BMP signaling plays a key role in regulating stem cell self-renewal and differentiation in the bone marrow niche. For example, a study by Tam and Nieuwenhuis showed that BMP2 and BMP4 signaling is required for the self-renewal of stem cells in the bone marrow niche. They used a combination of biochemical and genetic studies to show that BMP2/4 signaling is required to maintain stem cell quiescence, while BMP7 signals promote differentiation into erythrocyte progenitors. These results provide evidence that BMP signaling is an important regulator of stem cell self-renewal and differentiation in the bone marrow niche.