Dopamine regulation of Na+-K+-ATPase requires the PDZ-2 domain of sodium hydrogen regulatory factor-1 (NHERF-1) in opossum kidney cells

Salyer S, Lesousky N, Weinman EJ, Clark BJ, Lederer ED, Khundmiri SJ. Dopamine regulation of Na+K+-ATPase requires the PDZ-2 domain of sodium hydrogen regulatory factor-1 (NH-RF-1) in opossum kidney cells. Am J Physiol Cell Physiol 300: C425-C434, 2011. First published December 15, 2010; doi:10.1152/ajpcell.00357.2010.-Na+-K+-ATPase activity in renal proximal tubule is regulated by several hormones including parathyroid hormone (PTH) and dopamine. The current experiments explore the role of Na+/H+ exchanger regulatory factor 1 (NHERF-1) in dopamine-mediated regulation of Na+-K+-ATPase. We measured dopamine regulation of ouabain-sensitive Rb-86 uptake and Na+-K(+-)ATPase alpha 1 subunit phosphorylation in wild-type opossum kidney (OK) (OK-WT) cells, OKH cells (NHERF-1-deficient), and OKH cells stably transfected with full-length human NHERF-1 (NF) or NHERF-1 constructs with mutated PDZ-1 (Z1) or PDZ-2 (Z2) domains. Treatment with 1 mu M dopamine decreased ouabain-sensitive 86Rb uptake, increased phosphorylation of Na+-K+-ATPase alpha 1-subunit, and enhanced association of NHERF-1 with D1 receptor in OK-WT cells but not in OKH cells. Transfection with wild-type, full-length, or PDZ-1 domain-mutated NHERF-1 into OKH cells restored dopamine-mediated regulation of Na+-K+-ATPase and D1-like receptor association with NHERF-1. Dopamine did not regulate Na+-K+-ATPase or increase D1-like receptor association with NH-ERF-1 in OKH cells transfected with mutated PDZ-2 domain. Dopamine stimulated association of PKC-zeta with NHERF-1 in OK-WT and OKH cells transfected with full-length or PDZ-1 domain-mutated NHERF-1 but not in PDZ-2 domain-mutated NHERF-1-transfected OKH cells. These results suggest that NHERF-1 mediates Na+-K(+-)ATPase regulation by dopamine through its PDZ-2 domain.