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Induction of endogenous channels by high levels of heterologous membrane proteins in Xenopus oocytes.
Tzounopoulos T
,
Maylie J
,
Adelman JP
.
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Xenopus oocytes are widely employed for heterologous expression of cloned proteins, particularly electrogenic molecules such as ion channels and transporters. The high levels of expression readily obtained permit detailed investigations without interference from endogenous conductances. Injection of min K mRNA into Xenopus oocytes results in expression of voltage-dependent potassium-selective channels. Recent data show that injections of high concentrations of min K mRNA also induce a chloride current with very different biophysical, pharmacological, and regulatory properties from the min K potassium current. This led to the suggestion that the min K protein acts as an inducer of endogenous, normally silent oocyte ion channels. We now report that high levels of heterologous expression of many membrane proteins in Xenopus oocytes specifically induce this chloride current and a hyperpolarization-activated cation-selective current. The current is blocked by 4,4'-diisothiocyanostilbene-2-2'-disulphonic acid and tetraethylammonium, enhanced by clofilium, and is pH-sensitive. Criteria are presented that distinguish this endogenous current from those due to heterologous expression of electrogenic proteins in Xenopus oocytes. Together with structure-function studies, these results support the hypothesis that the min K protein comprises a potassium-selective channel.
Adelman,
Calcium-activated potassium channels expressed from cloned complementary DNAs.
1992,
Pubmed
,
Xenbase
Arriza,
Functional comparisons of three glutamate transporter subtypes cloned from human motor cortex.
1994,
Pubmed
,
Xenbase
Attali,
The protein IsK is a dual activator of K+ and Cl- channels.
1993,
Pubmed
,
Xenbase
Blumenthal,
The minK potassium channel exists in functional and nonfunctional forms when expressed in the plasma membrane of Xenopus oocytes.
1994,
Pubmed
,
Xenbase
Bond,
Cloning and expression of a family of inward rectifier potassium channels.
1994,
Pubmed
,
Xenbase
Bunzow,
Cloning and expression of a rat D2 dopamine receptor cDNA.
,
Pubmed
Christie,
Expression of a cloned rat brain potassium channel in Xenopus oocytes.
1989,
Pubmed
,
Xenbase
Dascal,
Atrial G protein-activated K+ channel: expression cloning and molecular properties.
1993,
Pubmed
,
Xenbase
Goldstein,
Site-specific mutations in a minimal voltage-dependent K+ channel alter ion selectivity and open-channel block.
1991,
Pubmed
,
Xenbase
Ho,
Cloning and expression of an inwardly rectifying ATP-regulated potassium channel.
1993,
Pubmed
,
Xenbase
Kowdley,
Hyperpolarization-activated chloride currents in Xenopus oocytes.
1994,
Pubmed
,
Xenbase
Kubo,
Primary structure and functional expression of a mouse inward rectifier potassium channel.
1993,
Pubmed
,
Xenbase
Kubo,
Primary structure and functional expression of a rat G-protein-coupled muscarinic potassium channel.
1993,
Pubmed
,
Xenbase
Miledi,
Chloride current induced by injection of calcium into Xenopus oocytes.
1984,
Pubmed
,
Xenbase
Parker,
A calcium-independent chloride current activated by hyperpolarization in Xenopus oocytes.
1988,
Pubmed
,
Xenbase
Pongs,
Molecular basis of potassium channel diversity.
1989,
Pubmed
,
Xenbase
Taglialatela,
Novel voltage clamp to record small, fast currents from ion channels expressed in Xenopus oocytes.
1992,
Pubmed
,
Xenbase
Takumi,
Cloning of a membrane protein that induces a slow voltage-gated potassium current.
1988,
Pubmed
,
Xenbase
Takumi,
Alteration of channel activities and gating by mutations of slow ISK potassium channel.
1991,
Pubmed
,
Xenbase
Timpe,
Expression of functional potassium channels from Shaker cDNA in Xenopus oocytes.
1988,
Pubmed
,
Xenbase
