Journal article
Regulation of ROMK1 channel by protein kinase A via a phosphatidylinositol 4,5-bisphosphate-dependent mechanism
Proceedings of the National Academy of Sciences - PNAS, Vol.96(10), pp.5820-5825
05/11/1999
DOI: 10.1073/pnas.96.10.5820
PMCID: PMC21944
PMID: 10318968
Abstract
ROMK inward-rectifier K
+
channels control renal K
+
secretion. The activity of ROMK is regulated by protein kinase A (PKA), but the molecular mechanism for regulation is unknown. Having found that direct interaction with membrane phosphatidylinositol 4,5-bisphosphate (PIP
2
) is essential for channel activation, we investigate here the role of PIP
2
in regulation of ROMK1 by PKA. By using adenosine-5′-[γ-thio]triphosphate) (ATP[γS]) as the substrate, we found that PKA does not directly activate ROMK1 channels in membranes that are devoid of PIP
2
. Rather, phosphorylation by PKA + ATP[γS] lowers the concentration of PIP
2
necessary for activation of the channels. In solution-binding assays, anti-PIP
2
antibodies bind PIP
2
and prevent PIP
2
–channel interaction. In inside-out membrane patches, antibodies inhibit the activity of the channels. PKA treatment then decreases the sensitivity of ROMK1 for inhibition by the antibodies, indicating an enhanced interaction between PIP
2
and the phosphorylated channels. Conversely, mutation of the PKA phosphorylation sites in ROMK1 decreases PIP
2
interaction with the channels. Thus, PKA activates ROMK1 channels by enhancing PIP
2
–channel interaction.
Details
- Title: Subtitle
- Regulation of ROMK1 channel by protein kinase A via a phosphatidylinositol 4,5-bisphosphate-dependent mechanism
- Creators
- Horng-Huei Liou - Department of Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, TX 75235-8856Shi-Sheng Zhou - Department of Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, TX 75235-8856Chou-Long Huang - Department of Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, TX 75235-8856
- Resource Type
- Journal article
- Publication Details
- Proceedings of the National Academy of Sciences - PNAS, Vol.96(10), pp.5820-5825
- DOI
- 10.1073/pnas.96.10.5820
- PMID
- 10318968
- PMCID
- PMC21944
- NLM abbreviation
- Proc Natl Acad Sci U S A
- ISSN
- 0027-8424
- eISSN
- 1091-6490
- Publisher
- National Academy of Sciences
- Language
- English
- Date published
- 05/11/1999
- Academic Unit
- Nephrology; Internal Medicine
- Record Identifier
- 9984094761902771
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