PGP and atrial fibrillation: Agp1-PGP (wild type, WT), Agp1-PGP-C279S/C295S, Agp1-PGP-C279S, Agp1-PGP-C295S, and Agp1-PGP-C279S/C295S/V364C (Figure 3A), were labeled with the pH-indicator dye 5-iodoacetamidofluorescein (5-IAF) to about 80–110%, yielding WT-AF, C279-AF, C295-AF, and V364C-AF.