FIGURE 9.

Graphical abstract. Proposed role for ABC acting as an allosteric modulator of the P2X7 receptor. ABC binds to a specific site of the receptor (site 2, allosteric binding site), but not to ATP-binding site (site 1), facilitating the endogenous ATP-P2X7R binding to site one and, thus, the activation of the receptor with low and physiological concentrations of ATP. This will lead to an increase in the expression of the adhesion molecule Mac-1 in PMN, which interacts with ICAM-1 on endothelial cells, causing the recruitment of leukocytes seen in the vascular inflammatory response induced by ABC. The release of ATP to the extracellular milieu through Connexin43 channels is also implicated in this response.