Figure 11.1.

Agonist-specific regulation of Ncx1. β-AR agonist isoproterenol (1 µM) or dobutamine (1 µM) activates CaMKinase II which then activates JunB and c-Jun, which sequentially binds to AP-1 elements and activates Ncx1 expression. α-AR agonist phenylephrine (10 µM) activates SRF via MAP kinase-p38 activation. SRF binds to CArG elements and mediates Ncx1 upregulation. HDACs regulate Ncx1 via the NKE element by deacetylating Nkx2.5. Inhibition of NCX1 by its reverse mode inhibitor KB-R7943 activates Ncx1 upregulation via activating MAP kinase p38 pathway