Fig. 6. Proposed mechanism of interplay between adenosine signalling and Cx26 hemichannels. The stimulation of A_2B adenosine receptors induces the synthesis of cAMP which activates the protein kinase A (PKA). The PKA in turn phosphorylates CREB and/or the specificity protein 1 (Sp1) resulting in an upregulation of Cx26 expression and synthesis. A proposed enhanced insertion of Cx hemichannels into the membrane leads to an increase in Cx hemichannel activity. Red labels indicate experimental confirmations.