Abstract
Eukaryotic cells coordinate specific responses to hormones and growth factors by spatial and temporal organization of “signaling components.” Through the formation of multiprotein complexes, cells are able to generate “signaling components” that transduce hormone signals through proteins, such as PSD-95/Dlg/ZO-1(PDZ)-containing proteins that associate by stable and dynamic interactions. The PDZ homology domain is a common protein interaction domain in eukaryotes and with greater than 500 PDZ domains identified, it is the most abundant protein interaction domain in eukaryotic cells. The NHERF (sodium hydrogen exchanger regulatory factor) proteins are PDZ domain-containing proteins that play an important role in maintaining and regulating cell function. NHERF-1 was initially identified as a brush border membrane-associated phosphoprotein essential for the cAMP/PKA-induced inhibition of the sodium hydrogen exchanger isoform 3 (NHE3). Mouse, rabbit and human renal proximal tubules also express NHERF-2 (E3KARP), a structurally related protein, which in model cell systems also binds NHE3 and mediates its inhibition by cAMP. PDZK1 (NHERF-3) and IKEPP (NHERF-4) were later identified and found to have similar homology domains, leading to their recent reclassification. Although studies have revealed similar binding partners and overlapping functions for the NHERF proteins, it is clear that there is a significant amount of specificity between them. This review focuses primarily on NHERF-1, as the prototypical PDZ protein and will give a brief summary of its role in phosphate transport and the development of some forms of nephrolithiasis.
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Acknowledgments
These studies were supported by grants from the National Institutes of Health DK55881 (EJW and SS), Research Service, Department of Veterans Affairs (EJW), the University of Maryland (RC) and the Kidney Foundation of Maryland (RC). R. Cunningham is a recipient of a Minority Career Development Award from the NIH and a Harold Amos Faculty Development award from the Robert Wood Johnson Foundation.
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Proceedings paper from the 3rd International Urolithiasis Research Symposium, Indianapolis, IN, USA, 3–4 December 2009.
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Cunningham, R., Biswas, R., Steplock, D. et al. Role of NHERF and scaffolding proteins in proximal tubule transport. Urol Res 38, 257–262 (2010). https://doi.org/10.1007/s00240-010-0294-1
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DOI: https://doi.org/10.1007/s00240-010-0294-1