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

Abstract

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 (86)Rb uptake and Na(+)-K(+)-ATPase α1 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 μM dopamine decreased ouabain-sensitive (86)Rb uptake, increased phosphorylation of Na(+)-K(+)-ATPase α1-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 NHERF-1 in OKH cells transfected with mutated PDZ-2 domain. Dopamine stimulated association of PKC-ζ 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.

Ezrin-Radixin-Moesin-binding Phosphoprotein 50 (EBP50) and Nuclear Factor-κB (NF-κB)

“…Indeed, our experiments show that inflammatory stimuli induce the formation of an EBP50-PKC complex at the cell membrane. The magnitude of this effect is consistent with that observed in kidney-derived opossum kidney cells (CHO) in response to dopamine (43). PKC translocation to the membrane appears to be the critical step for EBP50 action because NF-B activity in EBP50-null cells was rescued by a membranetargeted myristoylated form of PKC but not by overexpression of WT PKC.…”

Dietary phenylalanine-improved intestinal barrier health in young grass carp (Ctenopharyngodon idella) is associated with increased immune status and regulated gene expression of cytokines, tight junction proteins, antioxidant enzymes and related signalling molecules

“…In vitro, Phe can be metabolized to dopamine [15]. In opossum kidney cells, dopamine regulated the paracellular ion absorption through the PDZ domain [76]. Thus, Phe does not have a significant effect on the expression of claudin 12, and this may be partly due to the special structure of claudin 12, which needs further study.…”

Gastrin and D 1 Dopamine Receptor Interact to Induce Natriuresis and Diuresis

“…At least 50% of basal sodium excretion in moderately volume expanded states is mediated by the paracrine action of renal dopamine exerted on D 1 receptors (D 1 Rs) 9,10 . Dopamine, via D 1 R, inhibits the activity of Na + -K + -ATPase in the basolateral membrane and Na + /H + exchanger (NHE3) in the apical membrane of RPT cells 8,10–14 . A dysfunction of the D 1 R is involved in the pathogenesis of hypertension 8–10 .…”