Bone morphogenetic protein 4 (BMP-4) is a member of the bone morphogenetic protein (BMP) family and functions in a variety of developmental processes. BMP-4 is a critical element involved in the culture and differentiation of stem cells, including differentiation in mesoderm (cardiac and skeletal muscle cells and early hematopoietic cells) and ectoderm (neural cell types and skin cell types) from pluripotent stem cells (iPSC and ESC).