Portal de Periódicos da CAPES

Localization of the Na+/H+ exchanger isoform NHE-3 in rabbit and canine kidney

1994; Elsevier BV; Volume: 1195; Issue: 1 Linguagem: Inglês

10.1016/0005-2736(94)90013-2

1879-2642

Manoocher Soleimani, Crescence Bookstein, Gwen L. Bizal, Mark W. Musch, Yolanda J. Hattabaugh, Mrinalini C. Rao, Eugene B. Chang,

Ion channel regulation and function

The distribution and subcellular localization of Na+/H+ exchanger isoform NHE-3 was studied in rabbit and canine kidney using polyclonal antibodies to an NHE-3 fusion protein. Western blot analyses were performed against microsomal, brush-border, and basolateral membranes isolated from rabbit kidney cortex, outer medulla, and inner medulla. Immunoblots indicated that NHE-3 antibody recognized a strong band with 95–100 kDa molecular mass in cortical microsomes. Subcellular localization studies showed that NHE-3 was expressed in brush-border membranes of kidney cortex. Expression of NHE-3 in the medullary regions was studied by immunoblot analysis of NHE-3 antibody against the microsomal membranes from the outer and inner medulla. NHE-3 antibody specifically labelled a 95–100 kDa protein in outer but not inner medulla. Subcellular localization studies demonstrated that NHE-3 is localized to the brush-border membranes of the outer medulla. Immunoblot analysis against brush-border membranes from canine kidney cortex and outer medulla demonstrated the presence of an 83–90 kDa protein. The above experiments suggest that NHE-3 in rabbit kidney is a 95–100 kDa protein and is expressed in brush-border membranes of the cortex and outer medulla. The canine kidney NHE-3 is a 83–90 kDa protein and is expressed in brush-border membranes of the cortex and outer medulla. Based on its subcellular localization, we conclude that NHE-3 may be involved in vectorial Na+ and HCO3− transport and pHo regulation.