|
|
|
| Untersuchte Arbeit: Seite: 32, Zeilen: 1-22 |
Quelle: Boini 2006 Seite(n): 15, 16, Zeilen: 15: 16ff; 16: 18ff |
|---|---|
| Transepithelial Na+ transport in these segments is accomplished by Na+ entry into the epithelial cells via the epithelial Na+ channel (ENaC) in the luminal membrane and by exit of Na+ through the Na+, K+-ATPase in the basolateral plasma membrane. ENaC represents the rate limiting step in this process and is highly regulated (Kellenberger S. and Schild L., (2002) J Physiol). It is composed of three subunits (α, β and γ) (Canessa CM. et al., (1994) Nature; Lingueglia et al., (1993) FEBS Lett; Lingueglia et al., (1994) J Biol Chem) with a stoichiometry of 2α1β1γ (Firsov et al., (1998) EMBO J), although other stoichiometries have also been proposed (octa- or nonamers) (Eskandari et al., (1999) J Biol Chem; Snyder et al., (1998) J Biol Chem). Its subunits have a similar topology, with two transmembrane domains, one extracellular loop, and two cytoplasmic ends (Renard et al., (1994) J Biol Chem; Canessa CM. et al., (1994) Nature; Snyder et al., (1994) PMID). Each subunit also contains, at its C-terminal end, a PY-motif (P-P-X-Y, where P is a proline, Y a tyrosine, and X any amino acid), which is known as protein: protein interaction motifs that can interact with tryptophan (W)-rich WW domains (Chen HI. and Sudol M., (1995) Proc Natl Acad Sci USA; Staub O. and Rotin D., (1996) Am Physiol Soc).
The importance of these PY-motifs for ENaC regulation has been recognized by the findings that most cases of Liddle’s syndrome, K+-ATPase (Zecevic M. et al., (2004) Pflügers Arch; Setiawan I. et al., (2002) Pflügers Arch) with SGK1 profoundly increases the activity of both Na+- transporting proteins. Likewise, SGK2 and SGK3 stimulate ENaC (Friedrich B. et al., (2003) Pflügers Arch) and Na+- K+-ATPase (Henke G. et al., (2002) Kidney Blood Press Res). |
Transepithelial Na+ transport in these segments is accomplished by Na+ entry into the epithelial cells via the epithelial Na+ channel (ENaC) in the luminal membrane and by exit of Na+ through the Na+, K+-ATPase in the basolateral plasma membrane. ENaC represents the rate limiting step in this process and is highly regulated (Kellenberger and Schild 2002). It is composed of three subunits (α, β and γ) (Canessa et al., 1994; Canessa et al., 1994; Lingueglia et al., 1993; Lingueglia et al., 1994) with a stoichiometry of 2α1β1γ (Firsov et al., 1998), although other stoichiometries have also been proposed (octa- or nonamers) (Eskandari et al., 1999; Snyder et al., 1998). Its subunits have a similar topology, with two transmembrane domains, one extracellular loop, and two cytoplasmic ends (Renard et al., 1994; Canessa et al., 1994; Snyder et al., 1994). Each subunit also contains, at its C-terminal end, a PY-motif (P-P-X-Y, where P is a proline, Y a tyrosine, and X any amino acid), which is known as protein:protein interaction motifs that can interact with tryptophan (W)-rich WW domains (Chen and Sudol 1995; Staub and Rotin 1996). The importance of these PY-motifs for ENaC regulation has been recognized by the findings that most cases of Liddle’s syndrome [(Liddle et al., 1963)]
[p. 16]
|
The source is not mentioned. Note that the first sentence of the second paragraph makes little sense, as it is a combination of two unrelated half-sentences of the source, the first one ending just at the page break from page 15 to page 16. |
|