Connexin43 and Pannexin1 Channels in Osteoblasts: Who Is the “Hemichannel”?
- First Online:
- Cite this article as:
- Thi, M.M., Islam, S., Suadicani, S.O. et al. J Membrane Biol (2012) 245: 401. doi:10.1007/s00232-012-9462-2
- 328 Downloads
Osteoblasts sense and respond to mechanical stimuli in a process involving influx and release of large ions and signaling molecules. Unapposed gap junction hemichannels formed of connexin43 (Cx43) have been proposed as a major route for such exchange, in particular for release of ATP and prostaglandin E2 (PGE2) in osteocytes. However, we have found that Cx43-null osteoblasts have unaltered, mechanically induced PGE2 release and ATP-induced YoPro dye uptake. In contrast, PGE2 release in response to fluid shear stress is abolished in P2X7 receptor (P2X7R)–null osteoblasts, and ATP-induced dye uptake is attenuated following treatment of wild-type cells with a P2X7R or Pannexin1 (Panx1) channel blocker. These data indicate that Panx1 channels, in concert with P2X7R, likely form a molecular complex that performs the hemichannel function in osteoblast mechanosignaling.