Figure 5.

Schematic of sensors, signaling pathways, and responses involved in osteocyte mechanobiology. Fluid shear stress activates a mechanosensitive calcium channel in the plasma membrane, leading to Ca2+ influx through the voltage sensitive complex. Acting as a second messenger, Ca2+ promotes PGE2 synthesis via ATP and also inhibits NO generation. ERK1/2 induses transcription of Cx43 to form connexin hemichanels for PGE2 and ATP release. The action of canonical wnt on inhibition of SOST gene is also depicted. (see text for details).