Downregulation of NaPi-IIa and NaPi-IIb Na-coupled phosphate transporters by coexpression of Klotho.
Cell Physiol Biochem
; 28(2): 251-8, 2011.
Article
en En
| MEDLINE
| ID: mdl-21865732
Klotho, a transmembrane protein, protease and hormone has been shown to exert a profound effect on phosphate metabolism. Klotho overexpression lowers and Klotho deficiency increases the plasma phosphate concentration, effects in part attributed to an inhibitory effect of Klotho on the formation of 1,25-dihydroxycholecalciferol (1,25(OH) (2)D(3)), the active form of Vitamin D. Beyond that Klotho has been shown to decrease renal tubular phosphate transport more directly. The influence of Klotho on the plasma phosphate concentration contributes to the profound effect of Klotho on ageing and life span. The present study explored whether Klotho influences the major renal tubular (NaPi-IIa) and the major intestinal (NaPi-IIb) phosphate transporters. For functional analysis NaPi-IIa or NaPi-IIb were expressed in Xenopus oocytes both, without or with additional coexpression of Klotho and electrogenic phosphate transport was estimated from the phosphate-induced current (Ip). According to RT-PCR Klotho is expressed in the murine kidney and intestine. Coexpression of Klotho decreased Ip in both NaPi-IIa- and NaPi-IIb-expressing oocytes. Klotho decreased the maximal Ip without appreciably affecting the concentration required for halfmaximal Ip. Treatment of NaPi-IIa- or NaPi-IIb-expressing oocytes with Klotho protein similarly decreased Ip. In conclusion, Klotho down regulates both, renal (NaPi-IIa) and intestinal (NaPi-IIb) phosphate transporters.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Regulación hacia Abajo
/
Proteínas Cotransportadoras de Sodio-Fosfato de Tipo IIa
/
Proteínas Cotransportadoras de Sodio-Fosfato de Tipo IIb
/
Glucuronidasa
Límite:
Animals
Idioma:
En
Revista:
Cell Physiol Biochem
Asunto de la revista:
BIOQUIMICA
/
FARMACOLOGIA
Año:
2011
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Alemania