Long‐range coupling between the extracellular gates and the intracellular ATP binding domains of multidrug resistance protein pumps and cystic fibrosis transmembrane conductance regulator channels

• Published in: The FASEB journal 2016-03, Vol.30 (3), p.1247-1262
• Main Authors: Wei, Shipeng, Roessler, Bryan C., Icyuz, Mert, Chauvet, Sylvain, Tao, Binli, IV, John L. Hartman, Kirk, Kevin L.
• Format: Article
• Language: English
• Subjects: ABC transporter; Adenosine Triphosphatases - metabolism; Adenosine Triphosphate - genetics; Adenosine Triphosphate - metabolism; allostery; Amino Acid Sequence; ATP Binding Cassette Transporter, Sub-Family B - genetics; ATP Binding Cassette Transporter, Sub-Family B - metabolism; Binding Sites - genetics; Cell Line; Cyclic AMP-Dependent Protein Kinases - genetics; Cyclic AMP-Dependent Protein Kinases - metabolism; Cystic Fibrosis Transmembrane Conductance Regulator - genetics; Cystic Fibrosis Transmembrane Conductance Regulator - metabolism; HEK293 Cells; Humans; ion channel; Ion Channel Gating - genetics; Mutation - genetics; phosphorylation; Phosphorylation - genetics; Protein Binding - genetics; Protein Structure, Tertiary; Research Communication
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fj.15-278382

The ABCC transporter subfamily includes pumps, the long and short multidrug resistance proteins (MRPs), and an ATP‐gated anion channel, the cystic fibrosis transmembrane conductance regulator (CFTR). We show that despite their thermodynamic differences, these ABCC transporter subtypes use broadly similar mechanisms to couple their extracellular gates to the ATP occupancies of their cytosolic nucleotide binding domains. A conserved extracellular phenylalanine at this gate was a prime location for producing gain of function (GOF) mutants of a long MRP in yeast (Ycf1p cadmium transporter), a short yeast MRP (Yor1p oligomycin exporter), and human CFTR channels. Extracellular gate mutations rescued ATP binding mutants of the yeast MRPs and CFTR by increasing ATP sensitivity. Control ATPase‐defective MRP mutants could not be rescued by this mechanism. A CFTR double mutant with an extracellular gate mutation plus a cytosolic GOF mutation was highly active (single‐channel open probability >0.3) in the absence of ATP and protein kinase A, each normally required for CFTR activity. We conclude that all 3 ABCC transporter subtypes use similar mechanisms to couple their extracellular gates to ATP occupancy, and highly active CFTR channels that bypass defects in ATP binding or phosphorylation can be produced.—Wei, S., Roessler, B. C., Icyuz, M., Chauvet, S., Tao, B., Hartman IV, J. L., Kirk, K. L., Long‐range coupling between the extracellular gates and the intracellular ATP binding domains of multidrug resistance protein pumps and cystic fibrosis transmembrane conductance regulator channels. FASEB J. 30, 1247–1262 (2016). www.fasebj.org