TAT-Gap19 is a connexin43 (Cx43) hemichannel blocker, with an IC50 of 7 µM and no significant affinity for gap junctions or Panx1 channels. TAT-Gap19 is derived from Gap19, a sequence present on the intracellular cytoplasmic loop domain of Cx43, linked to the HIV-derived TAT internalization sequence to promote membrane permeability, which also allows brain penetration. In mouse models of liver damage, TAT-Gap19 can protect against liver fibrosis accompanied by superoxide dismutase overactivation and reduces production of inflammatory proteins.
