The amiloride-sensitive Na+ channel: from primary structure to function.
Three homologous subunits of the amiloride-sensitive Na+ channel, entitled alpha, beta, and gamma, have been cloned either from distal colon of a steroid-treated rat or from human lung. The alpha, beta, and gamma subunits have similarities with degenerins, a family of proteins found in the mechanosensory neurons of the nematode Caenorhabditis elegans. All these proteins are characterized by the presence of a large extracellular domain, located between two transmembrane alpha-helices, and by short NH2 and COOH terminal cytoplasmic segments. They constitute the first members of a new gene super-family of ionic channels. The epithelial Na+ channel is specifically expressed at the apical membrane of Na(+)-reabsorbing epithelial cells. Its activity is controlled by several distinct hormones, especially by corticosteroids. These hormones act either transcriptionally (such as aldosterone in distal colon, or glucocorticoids in lung) and/or post-transcriptionally (such as aldosterone in kidney). Recent works have provided new insights in the function of that important osmoregulatory system.
Voilley
N
N
Institut de Pharmacologie, Moléculaire et Cellulaire, CNRS UPR 411 600, Sophia Antipolis, Valbonne, France.
Galibert
A
A
Bassilana
F
F
Renard
S
S
Lingueglia
E
E
Coscoy
S
S
Champigny
G
G
Hofman
P
P
Lazdunski
M
M
Barbry
P
P
D000584:Amiloride / Q000494:pharmacology*; D000818:Animals; D004848:Epithelium / Q000737:chemistry / Q000187:drug effects; D006801:Humans; D005810:Multigene Family; D010446:Peptide Fragments / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis*; D015222:Sodium Channels / Q000187:drug effects*; D013256:Steroids / Q000494:pharmacology*; D013329:Structure-Activity Relationship
D010446:Peptide Fragments; D012333:RNA, Messenger; D015222:Sodium Channels; D013256:Steroids; D000584:Amiloride