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A Specific Functional Interaction between CHIF and Na,K‐ATPase
Author(s) -
GARTY HAIM,
LINDZEN MOSHIT,
FÜZESI MARIA,
AIZMAN ROMAN,
GOLDSHLEGER RIVKA,
ASHER CAROL,
KARLISH STEVEN J. D.
Publication year - 2003
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2003.tb07220.x
Subject(s) - gamma subunit , protein subunit , cytoplasm , g alpha subunit , extracellular , transfection , antibody , microbiology and biotechnology , chemistry , atpase , downregulation and upregulation , biology , biophysics , biochemistry , enzyme , immunology , gene
A bstract : CHIF (corticosteroid hormone‐induced factor) is a member of the FXYD family that shares ∼50% homology with the γ subunit of Na,K‐ATPase. It is expressed in renal collecting duct and distal colon, and is upregulated by Na + deprivation and high K + diet. Both CHIF and γ are coimmunoprecipitated by an anti‐α subunit antibody, and α is immunoprecipitated by anti‐γ and anti‐CHIF antibodies. 86 Rb + flux experiments in CHIF‐transfected HeLa cells demonstrate that CHIF increases the affinity for cytoplasmic Na + , but does not affect the affinity for extracellular K(Rb). A physiological role of CHIF in kidney function is further elucidated by the phenotypic analysis of CHIF knockout mice. Taken together with data by others, it appears that FXYD proteins are tissue‐specific subunits or regulators of the Na,K‐ATPase whose function is to adjust the pump kinetics to particular physiological needs.