Beyond gap junctions: Connexin43 and bone cell signaling

► Cx43 is the most abundant gap junction protein expressed in bone cells. ► Cx43 forms gap junctions, hemichannels and serves as a scaffold that regulates intracellular signaling in bone cells. ► Through these diverse mechanisms, Cx43 regulates the response of bone to pharmacologic, hormonal and mechanical stimuli. ► Understanding the role of Cx43 in bone cell function provides new opportunities to treat bone diseases.