The role of poorly researched connexins in musculoskeletal tissue: a brief review with emphasis on bone tissue

The connexins (Cxs) are a family of transmembrane proteins that form junctions in clefts and hemichannels responsible for mediating the communication between neighboring cells and the respective extracellular medium in different tissues. Most tissues and cells express one or more connexin proteins, playing an important role in the regulation of cell proliferation, differentiation, adhesion, migration and cell death, among other functions. In addition to acting as a channel, connexins can propagate intracellular signals through the C-terminal domain. Cx43 is the most expressed and best-connected connexin in bone and muscle tissue, although Cx40, Cx45, Cx46, and more recently Cx37, are also detected in bone. In turn, the expression of Cx26, Cx32 and Cx39 has been observed in other musculoskeletal tissues