Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
J Physiol
2003 Nov 15;553Pt 1:95-100. doi: 10.1113/jphysiol.2003.047910.
Show Gene links
Show Anatomy links
Polyamine flux in Xenopus oocytes through hemi-gap junctional channels.
Enkvetchakul D, Ebihara L, Nichols CG.
???displayArticle.abstract???
Diverse polyamine transport systems have been described in different cells, but the molecular entities that mediate polyamine influx and efflux remain incompletely defined. We have previously demonstrated that spermidine efflux from oocytes is a simple electrodiffusive process, inhibitable by external Ca2+, consistent with permeation through a membrane cation channel. Hemi-gap junctional channels in Xenopus oocytes are formed from connexin 38 (Cx38), and produce a calcium-sensitive (Ic) current that is inhibited by external Ca2+. Spermidine efflux is also calcium sensitive, and removal of external calcium increases both Ic currents and spermidine efflux in Xenopus oocytes. Injection of Cx38 cRNA or Cx38 antisense oligonucleotides (to increase or decrease, respectively, Cx38 expression) also increases or decreases spermidine efflux in parallel. Spermidine efflux has a large voltage-dependent component, which is abolished with injection of Cx38 antisense oligonucleotides. In addition, spermidine uptake is significantly increased in Cx38 cRNA-injected oocytes in the absence of external calcium. The data indicate that hemi-gap junctional channels provide the Ca2+-inhibited pathway for electrodiffusive efflux of polyamines from oocytes, and it is likely that hemi-gap junctional channels provide Ca2+ and metabolism-sensitive polyamine permeation pathways in other cells.
Arellano,
A monovalent cationic conductance that is blocked by extracellular divalent cations in Xenopus oocytes.
1995, Pubmed,
Xenbase
Arellano,
A monovalent cationic conductance that is blocked by extracellular divalent cations in Xenopus oocytes.
1995,
Pubmed
,
Xenbase Bianchi,
Regulation by spermine of native inward rectifier K+ channels in RBL-1 cells.
1996,
Pubmed Byers,
Regulation of polyamine transport in Chinese hamster ovary cells.
1990,
Pubmed Ebihara,
Xenopus connexin38 forms hemi-gap-junctional channels in the nonjunctional plasma membrane of Xenopus oocytes.
1996,
Pubmed
,
Xenbase Fage,
Ouabain releases striatal polyamines in vivo independently of N-methyl-D-aspartate receptor activation.
1993,
Pubmed Fage,
Selective release of spermine and spermidine from the rat striatum by N-methyl-D-aspartate receptor activation in vivo.
1992,
Pubmed Gilad,
Polyamine uptake, binding and release in rat brain.
1991,
Pubmed Igarashi,
Polyamine transport in bacteria and yeast.
1999,
Pubmed John,
Connexin-43 hemichannels opened by metabolic inhibition.
1999,
Pubmed Kano,
Polyamine transport and metabolism in mouse mammary gland. General properties and hormonal regulation.
1976,
Pubmed Kashiwagi,
Apparently unidirectional polyamine transport by proton motive force in polyamine-deficient Escherichia coli.
1986,
Pubmed Kashiwagi,
Spermidine-preferential uptake system in Escherichia coli. Identification of amino acids involved in polyamine binding in PotD protein.
1996,
Pubmed Kerschbaum,
Polyvalent cations as permeant probes of MIC and TRPM7 pores.
2003,
Pubmed Khan,
Mechanism of polyamine spermidine uptake by Xenopus laevis oocytes.
1990,
Pubmed
,
Xenbase Kondo,
Metabolic inhibition activates a non-selective current through connexin hemichannels in isolated ventricular myocytes.
2000,
Pubmed Li,
Properties and regulation of gap junctional hemichannels in the plasma membranes of cultured cells.
1996,
Pubmed Lopatin,
Potassium channel block by cytoplasmic polyamines as the mechanism of intrinsic rectification.
1994,
Pubmed
,
Xenbase Mackarel,
An investigation of the mechanism of polyamine efflux from human colorectal carcinoma cells.
1994,
Pubmed Musa,
Voltage-dependent blockade of connexin40 gap junctions by spermine.
2003,
Pubmed Nichols,
Inward rectification and implications for cardiac excitability.
1996,
Pubmed Nichols,
Inward rectifier potassium channels.
1997,
Pubmed Nicolas,
NMDA receptors with different sensitivities to magnesium and ifenprodil control the release of [14C]acetylcholine and [3H]spermidine from rat striatal slices in vitro.
1994,
Pubmed Poulin,
Inorganic cation dependence of putrescine and spermidine transport in human breast cancer cells.
1995,
Pubmed Saunders,
Pulmonary alveolar macrophages express a polyamine transport system.
1989,
Pubmed Seiler,
Polyamine transport in mammalian cells. An update.
1996,
Pubmed Sha,
Spermidine release from xenopus oocytes. Electrodiffusion through a membrane channel.
1996,
Pubmed
,
Xenbase Sha,
Heterologous expression of the Na(+),K(+)-ATPase gamma subunit in Xenopus oocytes induces an endogenous, voltage-gated large diameter pore.
2001,
Pubmed
,
Xenbase Shyng,
Depletion of intracellular polyamines relieves inward rectification of potassium channels.
1996,
Pubmed
,
Xenbase Sugiyama,
The 1.8-A X-ray structure of the Escherichia coli PotD protein complexed with spermidine and the mechanism of polyamine binding.
1996,
Pubmed Tjandrawinata,
Characterization of putrescine and cadaverine export in mammalian cells. A pharmacological approach.
1994,
Pubmed Tupper,
The ionic permeability of the amphibian oocyte in the presence or absence of external calcium.
1973,
Pubmed Wallace,
Factors affecting polyamine excretion from mammalian cells in culture. Inhibitors of polyamine biosynthesis.
1986,
Pubmed Wallace,
Uptake and excretion of polyamines from baby hamster kidney cells (BHK-21/C13). The effect of serum on confluent cell cultures.
1981,
Pubmed Williams,
Interactions of polyamines with ion channels.
1997,
Pubmed Zhang,
The ion selectivity of a membrane conductance inactivated by extracellular calcium in Xenopus oocytes.
1998,
Pubmed
,
Xenbase
