Journal article
Klotho Up-regulates Renal Calcium Channel Transient Receptor Potential Vanilloid 5 (TRPV5) by Intra- and Extracellular N-glycosylation-dependent Mechanisms
The Journal of biological chemistry, Vol.289(52), pp.35849-35857
12/26/2014
DOI: 10.1074/jbc.M114.616649
PMCID: PMC4276853
PMID: 25378396
Abstract
The anti-aging protein Klotho is a type 1 membrane protein produced predominantly in the distal convoluted tubule. The ectodomain of Klotho is cleaved and secreted into the urine to regulate several ion channels and transporters. Secreted Klotho (sKL) up-regulates the TRPV5 calcium channel from the cell exterior by removing sialic acids from N-glycan of the channel and inhibiting its endocytosis. Because TRPV5 and Klotho coexpress in the distal convoluted tubule, we investigated whether Klotho regulates TRPV5 action from inside the cell. Whole-cell TRPV5-mediated channel activity was recorded in HEK cells coexpressing TRPV5 and sKL or membranous Klotho (mKL). Transfection of sKL, but not mKL, produced detectable Klotho protein in cell culture media. As for sKL, mKL increased TRPV5 current density. The role of sialidase activity of mKL acting inside is supported by findings that mutations of putative sialidase activity sites in sKL and mKL abrogated the regulation of TRPV5 but that the extracellular application of a sialidase inhibitor prevented the regulation of TRPV5 by sKL only. Mechanistically, coexpression with a dominant-negative dynamin II prevented the regulation of TRPV5 by sKL but not by mKL. In contrast, blocking forward trafficking by brefeldin A prevented the effect with mKL but not with sKL. Therefore, Klotho up-regulates TRPV5 from both the inside and outside of cells. The intracellular action of Klotho is likely due to enhanced forward trafficking of channel proteins, whereas the extracellular action is due to inhibition of endocytosis. Both effects involve putative Klotho sialidase activity. These effects of Klotho may play important roles regarding calcium reabsorption in the kidney.Klotho is a putative sialidase that modifies the extracellular N-glycan of TRPV5 to increase its surface expression.
Intracellular expression of Klotho increased TRPV5 via an N-glycosylation-dependent mechanism that requires the sialidase activity of Klotho.
Klotho up-regulates TRPV5 surface abundance by intra- and extracellular mechanisms.
We investigate a novel function of Klotho to regulate intracellular protein trafficking via enzymatic activity.
Details
- Title: Subtitle
- Klotho Up-regulates Renal Calcium Channel Transient Receptor Potential Vanilloid 5 (TRPV5) by Intra- and Extracellular N-glycosylation-dependent Mechanisms
- Creators
- Matthias T.F. Wolf - Departments of Pediatrics, Dallas, Texas 75390Sung-Wan An - The University of Texas Southwestern Medical CenterMingzhu Nie - From the Departments of Pediatrics and.Manjot S. Bal - From the Departments of Pediatrics and.Chou-Long Huang - The University of Texas Southwestern Medical Center
- Resource Type
- Journal article
- Publication Details
- The Journal of biological chemistry, Vol.289(52), pp.35849-35857
- DOI
- 10.1074/jbc.M114.616649
- PMID
- 25378396
- PMCID
- PMC4276853
- NLM abbreviation
- J Biol Chem
- ISSN
- 0021-9258
- eISSN
- 1083-351X
- Publisher
- Elsevier Inc
- Grant note
- DOI: 10.13039/100000002, name: National Institutes of Health, award: RO1-DK85726, K08-DK095994-02, K12-HD000850
- Language
- English
- Date published
- 12/26/2014
- Academic Unit
- Nephrology; Internal Medicine
- Record Identifier
- 9984359837502771
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