A novel spliced variant of the epithelial Na+ channel delta-subunit in the human brain.
The amiloride-sensitive epithelial Na+ channel regulates Na+ homeostasis in cells. Recently, we described that the delta-subunit is a candidate molecule for a pH sensor in the human brain. Here, an N-terminal spliced variant of the delta-subunit is cloned from human brain, and designated as the delta2-subunit, which is expressed with the original delta-subunit (delta1-subunit) at the same level in the human brain. Functional analyses revealed that the physiological and pharmacological properties (interaction with accessory betagamma-subunits, activation by acidic pH, amiloride sensitivity) of the delta2-subunit were similar to those of the delta1-subunit. In conclusion, the activities of both subunits may be involved in the mechanism underlying pH sensing in the human brain.
Yamamura
Hisao
H
Department of Molecular Morphology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan. yamamura@med.nagoya-cu.ac.jp
Ugawa
Shinya
S
Ueda
Takashi
T
Nagao
Masataka
M
Shimada
Shoichi
S
D017398:Alternative Splicing; D000584:Amiloride / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism*; D053503:Epithelial Sodium Channels; D006801:Humans; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D015222:Sodium Channels / Q000096:biosynthesis / Q000737:chemistry*; D014982:Xenopus laevis / Q000378:metabolism
D053503:Epithelial Sodium Channels; D015222:Sodium Channels; D000584:Amiloride