---
_id: '54944'
abstract:
- lang: eng
  text: 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.
author:
- first_name: Silke
  full_name: Haerteis, Silke
  last_name: Haerteis
- first_name: Bettina
  full_name: Krueger, Bettina
  id: '49428'
  last_name: Krueger
  orcid: 0000-0001-5351-1785
- first_name: Christoph
  full_name: Korbmacher, Christoph
  last_name: Korbmacher
- first_name: Robert
  full_name: Rauh, Robert
  last_name: Rauh
citation:
  ama: Haerteis S, Krueger B, Korbmacher C, Rauh R. The $\delta$-Subunit of the Epithelial
    Sodium Channel (ENaC) Enhances Channel Activity and Alters Proteolytic ENaC Activation.
    <i>Journal of Biological Chemistry</i>. 2009;284(42):29024–29040. doi:<a href="https://doi.org/10.1074/jbc.m109.018945">10.1074/jbc.m109.018945</a>
  apa: Haerteis, S., Krueger, B., Korbmacher, C., &#38; Rauh, R. (2009). The $\delta$-Subunit
    of the Epithelial Sodium Channel (ENaC) Enhances Channel Activity and Alters Proteolytic
    ENaC Activation. <i>Journal of Biological Chemistry</i>, <i>284</i>(42), 29024–29040.
    <a href="https://doi.org/10.1074/jbc.m109.018945">https://doi.org/10.1074/jbc.m109.018945</a>
  bibtex: '@article{Haerteis_Krueger_Korbmacher_Rauh_2009, title={The $\delta$-Subunit
    of the Epithelial Sodium Channel (ENaC) Enhances Channel Activity and Alters Proteolytic
    ENaC Activation}, volume={284}, DOI={<a href="https://doi.org/10.1074/jbc.m109.018945">10.1074/jbc.m109.018945</a>},
    number={42}, journal={Journal of Biological Chemistry}, publisher={American Society
    for Biochemistry and Molecular Biology}, author={Haerteis, Silke and Krueger,
    Bettina and Korbmacher, Christoph and Rauh, Robert}, year={2009}, pages={29024–29040}
    }'
  chicago: 'Haerteis, Silke, Bettina Krueger, Christoph Korbmacher, and Robert Rauh.
    “The $\delta$-Subunit of the Epithelial Sodium Channel (ENaC) Enhances Channel
    Activity and Alters Proteolytic ENaC Activation.” <i>Journal of Biological Chemistry</i>
    284, no. 42 (2009): 29024–29040. <a href="https://doi.org/10.1074/jbc.m109.018945">https://doi.org/10.1074/jbc.m109.018945</a>.'
  ieee: 'S. Haerteis, B. Krueger, C. Korbmacher, and R. Rauh, “The $\delta$-Subunit
    of the Epithelial Sodium Channel (ENaC) Enhances Channel Activity and Alters Proteolytic
    ENaC Activation,” <i>Journal of Biological Chemistry</i>, vol. 284, no. 42, pp.
    29024–29040, 2009, doi: <a href="https://doi.org/10.1074/jbc.m109.018945">10.1074/jbc.m109.018945</a>.'
  mla: Haerteis, Silke, et al. “The $\delta$-Subunit of the Epithelial Sodium Channel
    (ENaC) Enhances Channel Activity and Alters Proteolytic ENaC Activation.” <i>Journal
    of Biological Chemistry</i>, vol. 284, no. 42, American Society for Biochemistry
    and Molecular Biology, 2009, pp. 29024–29040, doi:<a href="https://doi.org/10.1074/jbc.m109.018945">10.1074/jbc.m109.018945</a>.
  short: S. Haerteis, B. Krueger, C. Korbmacher, R. Rauh, Journal of Biological Chemistry
    284 (2009) 29024–29040.
date_created: 2024-06-30T13:58:07Z
date_updated: 2024-06-30T13:58:15Z
department:
- _id: '35'
- _id: '22'
doi: 10.1074/jbc.m109.018945
intvolume: '       284'
issue: '42'
language:
- iso: eng
page: 29024–29040
publication: Journal of Biological Chemistry
publisher: American Society for Biochemistry and Molecular Biology
status: public
title: The $\delta$-Subunit of the Epithelial Sodium Channel (ENaC) Enhances Channel
  Activity and Alters Proteolytic ENaC Activation
type: journal_article
user_id: '49428'
volume: 284
year: '2009'
...