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Dynamics of PTH-induced disassembly of Npt2a/NHERF-1 complexes in living OK cells.
Abstract
Parathyroid hormone (PTH) inhibits the reabsorption of phosphate in the renal proximal
tubule by disrupting the binding of the sodium-dependent phosphate transporter 2A
(Npt2a) to the adapter protein sodium-hydrogen exchanger regulatory factor-1 (NHERF-1),
a process initiated by activation of protein kinase C (PKC). To gain additional insights
into the dynamic sequence of events, the time course of these responses was studied
in living opossum kidney (OK) cells. Using a FRET-based biosensor, we found that PTH
activated intracellular PKC within seconds to minutes. In cells expressing GFP-Npt2a
and mCherry-NHERF, PTH did not affect the relative abundance of NHERF-1 but there
was a significant and time-dependent decrease in the Npt2a/NHERF-1 ratio. The half-time
to maximal dissociation was 15 to 20 min. By contrast, PTH had no effect on the fluorescence
ratio for GFP-ezrin compared with mCherry-NHERF-1 at the apical surface. These experiments
establish that PTH treatment of proximal tubule OK cells leads to rapid activation
of PKC with the subsequent dissociation of Npt2a/NHERF-1 complexes. The association
of NHERF-1 with Ezrin and their localization at the apical membrane, however, was
unperturbed by PTH, thereby enabling the rapid recruitment and membrane reinsertion
of Npt2a and other NHERF-1 targets on termination of the hormone response.
Type
Journal articleSubject
KidneyCell Line
Animals
Opossums
Multiprotein Complexes
Parathyroid Hormone
Sodium-Hydrogen Antiporter
Cytoskeletal Proteins
Phosphoproteins
Female
Sodium-Phosphate Cotransporter Proteins, Type IIa
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https://hdl.handle.net/10161/17232Published Version (Please cite this version)
10.1152/ajprenal.00532.2010Publication Info
Weinman, Edward J; Steplock, Deborah; Shenolikar, Shirish; & Blanpied, Thomas A (2011). Dynamics of PTH-induced disassembly of Npt2a/NHERF-1 complexes in living OK cells.
American journal of physiology. Renal physiology, 300(1). pp. F231-F235. 10.1152/ajprenal.00532.2010. Retrieved from https://hdl.handle.net/10161/17232.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Shirish Shenolikar
Professor Emeritus of Psychiatry and Behavioral Sciences
Protein phosphorylation controls a wide range of physiological processes in mammalian
tissues. Phosphorylation state of cellular proteins is controlled by the opposing
actions of protein kinases and phosphatases that are regulated by hormones, neurotransmitters,
growth factors and other environmental cues. Our research attempts to understand the
communication between protein kinases and phosphatases that dictates cellular protein
phosphorylation and the cell's response to hormones. Over the

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