Connexin43 Gap Junctions Influences Osteoblast Signalling and Enhances Osteoarthritis Gene Expression

In multicellular organism, cells communicate with each other by gap junctions. The subunits of gap junction channels are proteins called connexins. Six-connexin proteins interact to form a ring-like pore structure called a hemichannel or connexon.

These hemichannels dock to hemichannels on neighbouring cells, forming a gap junction’s pore, which provides a direct intercellular passage for small molecules               or ion to move between cells. Most of the gap junction possesses four transmembrane regions, with cytoplasmic amino and carboxyl regions.

Gap junction communication plays a critical role in bone cells such as osteoblast, osteocytes and osteoclast. In humans, more than twenty connexins have been identified but Cx43, Cx45, Cx40, Cx46 and Cx37 are expressed in the bone.

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