BMP2 and osteoporosis: Phosphorylated Smads1/5/8 forms a complex with Smad4 and translocates to the nucleus, whereby it regulates the transcription of bone-specific genes.(19–23) Emerging evidence suggests that BMP-2 has an ameliorative effect on osteoporosis.(24) Therefore, it is desirable to identify compounds capable of inducing endogenous BMP-2 production in bone cells.