Topala CN, Bindels RJM, Hoenderop JGJ. Regulation of the epithelial calcium channel TRPV5 by extracellular factors.
Curr Opin Nephrol Hypertens 2007;
16:319-24. [PMID:
17565273 DOI:
10.1097/mnh.0b013e3281c55f02]
[Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
PURPOSE OF REVIEW
Recent studies have greatly increased our knowledge concerning the regulation of renal calcium handling. This review focuses on newly identified calciotropic factors present in the pro-urine and the mechanisms by which they control the transient receptor potential channel vanilloid subtype 5 (TRPV5) which forms the gatekeeper of active renal calcium reabsorption.
RECENT FINDINGS
The antiaging hormone klotho regulates TRPV5 activity via a novel mechanism modifying its glycosylation status, thereby entrapping the channel at the cell surface. Functional characterization of tissue kallikrein knockout mice revealed that these animals exhibit a pronounced hypercalciuria, comparable to the calcium leak observed in TRPV5 knockout mice. Recently, it has been demonstrated that tissue kallikrein stimulates active calcium reabsorption via the bradykinin receptor type 2 pathway involving protein kinase C-dependent activation of TRPV5. Finally, the extracellular pH appears to act as a dynamic switch controlling cell surface expression of TRPV5.
SUMMARY
Unraveling the molecular mechanisms of TRPV5 channel regulation by the antiaging hormone klotho, tissue kallikrein and extracellular pH demonstrated the existence of novel regulatory mechanisms of active calcium reabsorption acting from the tubular lumen.
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