---
res:
  bibo_abstract:
  - The epithelial sodium channel (ENaC) is probably a heterotrimer with three well
    characterized subunits (alphabetagamma). In humans an additional delta-subunit
    (delta-hENaC) exists but little is known about its function. Using the Xenopus
    laevis oocyte expression system, we compared the functional properties of alphabetagamma-
    and deltabetagamma-hENaC and investigated whether deltabetagamma-hENaC can be
    proteolytically activated. The amiloride-sensitive ENaC whole-cell current (DeltaI(ami))
    was about 11-fold larger in oocytes expressing deltabetagamma-hENaC than in oocytes
    expressing alphabetagamma-hENaC. The 2-fold larger single-channel Na(+) conductance
    of deltabetagamma-hENaC cannot explain this difference. Using a chemiluminescence
    assay, we demonstrated that an increased channel surface expression is also not
    the cause. Thus, overall channel activity of deltabetagamma-hENaC must be higher
    than that of alphabetagamma-hENaC. Experiments exploiting the properties of the
    known betaS520C mutant ENaC confirmed this conclusion. Moreover, chymotrypsin
    had a reduced stimulatory effect on deltabetagamma-hENaC whole-cell currents compared
    with its effect on alphabetagamma-hENaC whole-cell currents (2-fold versus 5-fold).
    This suggests that the cell surface pool of so-called near-silent channels that
    can be proteolytically activated is smaller for deltabetagamma-hENaC than for
    alphabetagamma-hENaC. Proteolytic activation of deltabetagamma-hENaC was associated
    with the appearance of a delta-hENaC cleavage product at the cell surface. Finally,
    we demonstrated that a short inhibitory 13-mer peptide corresponding to a region
    of the extracellular loop of human alpha-ENaC inhibited DeltaI(ami) in oocytes
    expressing alphabetagamma-hENaC but not in those expressing deltabetagamma-hENaC.
    We conclude that the delta-subunit of ENaC alters proteolytic channel activation
    and enhances base-line channel activity.@eng
  bibo_authorlist:
  - foaf_Person:
      foaf_givenName: Silke
      foaf_name: Haerteis, Silke
      foaf_surname: Haerteis
  - foaf_Person:
      foaf_givenName: Bettina
      foaf_name: Krueger, Bettina
      foaf_surname: Krueger
      foaf_workInfoHomepage: http://www.librecat.org/personId=49428
    orcid: 0000-0001-5351-1785
  - foaf_Person:
      foaf_givenName: Christoph
      foaf_name: Korbmacher, Christoph
      foaf_surname: Korbmacher
  - foaf_Person:
      foaf_givenName: Robert
      foaf_name: Rauh, Robert
      foaf_surname: Rauh
  bibo_doi: 10.1074/jbc.m109.018945
  bibo_issue: '42'
  bibo_volume: 284
  dct_date: 2009^xs_gYear
  dct_language: eng
  dct_publisher: American Society for Biochemistry and Molecular Biology@
  dct_title: The $\delta$-Subunit of the Epithelial Sodium Channel (ENaC) Enhances
    Channel Activity and Alters Proteolytic ENaC Activation@
...