Fig. 6
Osteocyte gap junctions and hemichannels in mechanobiology. a Illustration of osteocyte GJs in response to mechanical stimulation. A hexameric array of six connexin subunits gives rise to a connexon, and two juxtaposed connexons on the surfaces of adjacent cells form a GJ.91,92 When osteocytes experience mechanical stimulation, the Cx43 protein is phosphorylated, and the connexon is opened, allowing the exchange of several effectors, such as calcium, ATP, PGE2, and cAMP, between connecting cells. b Illustration of osteocyte hemichannels in response to mechanical stimulation. Unopposed connexons called hemichannels at the cell membrane act as direct conduits between the cytosol and extracellular environment.91c Signaling pathways involved in Cx43-based GJs and hemichannels during osteocyte mechanobiology
