Function and expression of a novel rat salt-tolerant protein: evidence of a role in cellular sodium metabolism.
Higher dietary salt intake in humans is associated with higher BP, but the BP response to NaCl, so-called salt sensitivity, is heterogeneous among individuals. It has been postulated that modifications in cellular cation metabolism may be related to salt sensitivity in mammalian hypertension. The authors have isolated a novel rat complementary DNA, called salt-tolerant protein (STP), that can functionally complement Saccharomyces cervisiae HAL1, which improves salt tolerance by modulating the cation transport system. On high-salt (8% NaCl) diets, both Dahl salt-sensitive and salt-resistant rats displayed an elevated BP and increased STP mRNA expression. Immunohistochemistry using an anti-rat STP antibody demonstrated the presence of STP immunoreactivity in the proximal tubules. In cells that transiently expressed STP, the intracellular [Na+]/[K+] ratio was higher than that in control cells. STP contains predicted coiled-coil and Src homology 3 domains, and shows a partially high degree of nucleotide identity to human thyroid-hormone receptor interacting protein. These results suggest that STP may play an important role in salt sensitivity through cellular sodium metabolism by mediating signal transduction and a hormone-dependent transcription mechanism.
Tsuji
E
E
Second Department of Internal Medicine, School of Medicine, Fukuoka University, Japan.
Tsuji
Y
Y
Sasaguri
M
M
Arakawa
K
K
D000595:Amino Acid Sequence; D000704:Analysis of Variance; D000818:Animals; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D046508:Culture Techniques; D018076:DNA, Complementary / Q000032:analysis; D004195:Disease Models, Animal; D005656:Fungal Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D007150:Immunohistochemistry; D007672:Kidney Cortex / Q000378:metabolism* / Q000473:pathology; D007679:Kidney Medulla / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008869:Microtubule-Associated Proteins; D015778:Minor Histocompatibility Antigens; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D020303:Rats, Inbred Dahl; D017208:Rats, Wistar; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage / Q000378:metabolism*
D002352:Carrier Proteins; D018076:DNA, Complementary; D005656:Fungal Proteins; D008869:Microtubule-Associated Proteins; D015778:Minor Histocompatibility Antigens; D012333:RNA, Messenger; D017673:Sodium Chloride, Dietary; C498640:Trip10 protein, rat