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.
Cloning and characterization of glioma BK, a novel BK channel isoform highly expressed in human glioma cells.
Liu X
,
Chang Y
,
Reinhart PH
,
Sontheimer H
,
Chang Y
.
???displayArticle.abstract???
Voltage-dependent large-conductance Ca2+-activated K+ channels (BK channels) are widely expressed in excitable and nonexcitable cells. BK channels exhibit diverse electrophysiological properties, which are attributable in part to alternative splicing of their alpha-subunits. BK currents have been implicated in the growth control of glial cells, and BK channels with novel biophysical properties have recently been characterized in human glioma cells. Here we report the isolation, cloning, and functional characterization of glioma BK (gBK), a novel splice isoform of hSlo, the gene that encodes the alpha-subunits of human BK channels. The primary sequence of gBK is 97% identical to its closest homolog hbr5, but it contains an additional 34-amino-acid exon at splice site 2 in the C-terminal tail of BK channels. hSlo transcripts containing this novel exon are expressed ubiquitously in various normal tissues as well as in neoplasmic samples, suggesting that the novel exon may modulate important physiological functions of BK channels. Expression of gBK in Xenopus oocytes gives rise to iberiotoxin-sensitive (IbTX) currents, with an IC(50) for IbTX of 5.7 nm and a Hill coefficient of 0.76. Single gBK channels have a unitary conductance of similar250 pS, and the currents show significantly slower activation and higher Ca2+ sensitivity than hbr5. Ca2+ sensitivity was enhanced specifically at physiologically relevant [Ca2+]i (100-500 nm). Examination of biopsies from patients with malignant gliomas has revealed specific overexpression of BK channels in gliomas compared with nonmalignant human cortical tissues. Importantly, tumor malignancy grades have correlated positively with BK channel expression, suggesting an important role for the gBK channel in glioma biology.
Adelman,
Calcium-activated potassium channels expressed from cloned complementary DNAs.
1992,
Pubmed
,
Xenbase
Atkinson,
A component of calcium-activated potassium channels encoded by the Drosophila slo locus.
1991,
Pubmed
Brenner,
Vasoregulation by the beta1 subunit of the calcium-activated potassium channel.
2000,
Pubmed
Bringmann,
Human Müller glial cells: altered potassium channel activity in proliferative vitreoretinopathy.
1999,
Pubmed
Bringmann,
Role of glial K(+) channels in ontogeny and gliosis: a hypothesis based upon studies on Müller cells.
2000,
Pubmed
Bringmann,
Heterogenous expression of Ca2+-dependent K+ currents by Müller glial cells.
1997,
Pubmed
Bringmann,
Mammalian retinal glial (Müller) cells express large-conductance Ca(2+)-activated K+ channels that are modulated by Mg2+ and pH and activated by protein kinase A.
1997,
Pubmed
Brismar,
Potassium and sodium channels in human malignant glioma cells.
1989,
Pubmed
Butler,
mSlo, a complex mouse gene encoding "maxi" calcium-activated potassium channels.
1993,
Pubmed
,
Xenbase
Christensen,
Maxi K+ channels in leaky epithelia are regulated by intracellular Ca2+, pH and membrane potential.
1987,
Pubmed
Collins,
Epidermal growth factor receptor gene and its transcripts in glioblastomas.
1994,
Pubmed
DeCoursey,
Ion channel expression in PMA-differentiated human THP-1 macrophages.
1996,
Pubmed
Ding,
Astrocyte-specific expression of activated p21-ras results in malignant astrocytoma formation in a transgenic mouse model of human gliomas.
2001,
Pubmed
Ferrer,
Cloning of human pancreatic islet large conductance Ca(2+)-activated K+ channel (hSlo) cDNAs: evidence for high levels of expression in pancreatic islets and identification of a flanking genetic marker.
1996,
Pubmed
Gallin,
Calcium- and voltage-activated potassium channels in human macrophages.
1984,
Pubmed
Gitter,
High-conductance K+ channel in apical membranes of principal cells cultured from rabbit renal cortical collecting duct anlagen.
1987,
Pubmed
Golding,
Dendritic calcium spike initiation and repolarization are controlled by distinct potassium channel subtypes in CA1 pyramidal neurons.
1999,
Pubmed
Hamill,
Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches.
1981,
Pubmed
Hanaoka,
A 59 amino acid insertion increases Ca(2+) sensitivity of rbslo1, a Ca2+ -activated K(+) channel in renal epithelia.
1999,
Pubmed
Hernández,
Lysophosphatidic acid inhibits Ca2+ signaling in response to epidermal growth factor receptor stimulation in human astrocytoma cells by a mechanism involving phospholipase C(gamma) and a G(alphai) protein.
2000,
Pubmed
Huang,
Potassium channel induction by the Ras/Raf signal transduction cascade.
1994,
Pubmed
Hurley,
Characterization and regulation of Ca2+-dependent K+ channels in human esophageal smooth muscle.
1999,
Pubmed
Jones,
The functional role of alternative splicing of Ca(2+)-activated K+ channels in auditory hair cells.
1999,
Pubmed
,
Xenbase
Kamouchi,
Functional effects of expression of hslo Ca2+ activated K+ channels in cultured macrovascular endothelial cells.
1997,
Pubmed
Kodal,
Involvement of calcium-activated potassium channels in the regulation of DNA synthesis in cultured Müller glial cells.
2000,
Pubmed
Lagrutta,
Functional differences among alternatively spliced variants of Slowpoke, a Drosophila calcium-activated potassium channel.
1994,
Pubmed
Lerche,
Characterization of the high-conductance Ca(2+)-activated K+ channel in adult human skeletal muscle.
1995,
Pubmed
Lingle,
Calcium-activated potassium channels in adrenal chromaffin cells.
1996,
Pubmed
MacDermott,
Action potential repolarization may involve a transient, Ca2+-sensitive outward current in a vertebrate neurone.
1982,
Pubmed
Marks,
Preparation of solutions with free calcium concentration in the nanomolar range using 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid.
1991,
Pubmed
Marty,
The physiological role of calcium-dependent channels.
1989,
Pubmed
McCobb,
A human calcium-activated potassium channel gene expressed in vascular smooth muscle.
1995,
Pubmed
,
Xenbase
McManus,
Calcium-activated potassium channels: regulation by calcium.
1991,
Pubmed
Merzak,
Molecular and cellular pathology of intrinsic brain tumours.
1997,
Pubmed
Miledi,
A calcium-dependent transient outward current in Xenopus laevis oocytes.
1982,
Pubmed
,
Xenbase
Nelson,
Physiological roles and properties of potassium channels in arterial smooth muscle.
1995,
Pubmed
Newman,
Voltage-dependent calcium and potassium channels in retinal glial cells.
,
Pubmed
Nowak,
Ionic channels in mouse astrocytes in culture.
1987,
Pubmed
Poolos,
Calcium-activated potassium conductances contribute to action potential repolarization at the soma but not the dendrites of hippocampal CA1 pyramidal neurons.
1999,
Pubmed
Puro,
Retinal glial cell proliferation and ion channels: a possible link.
1989,
Pubmed
Ramanathan,
A molecular mechanism for electrical tuning of cochlear hair cells.
1999,
Pubmed
Ransom,
BK channels in human glioma cells.
2001,
Pubmed
Repp,
Profound differences in potassium current properties of normal and Rous sarcoma virus-transformed chicken embryo fibroblasts.
1993,
Pubmed
Robitaille,
Functional colocalization of calcium and calcium-gated potassium channels in control of transmitter release.
1993,
Pubmed
Robitaille,
Presynaptic calcium signals and transmitter release are modulated by calcium-activated potassium channels.
1992,
Pubmed
Ruknudin,
The ultrastructure of patch-clamped membranes: a study using high voltage electron microscopy.
1991,
Pubmed
,
Xenbase
Saito,
A cysteine-rich domain defined by a novel exon in a slo variant in rat adrenal chromaffin cells and PC12 cells.
1997,
Pubmed
,
Xenbase
Schreiber,
A novel calcium-sensing domain in the BK channel.
1997,
Pubmed
,
Xenbase
Schreiber,
Transplantable sites confer calcium sensitivity to BK channels.
1999,
Pubmed
,
Xenbase
Soroceanu,
Modulation of glioma cell migration and invasion using Cl(-) and K(+) ion channel blockers.
1999,
Pubmed
Tian,
Alternative splicing switches potassium channel sensitivity to protein phosphorylation.
2001,
Pubmed
Tseng-Crank,
Cloning, expression, and distribution of functionally distinct Ca(2+)-activated K+ channel isoforms from human brain.
1994,
Pubmed
,
Xenbase
Turnheim,
Reconstitution of a calcium-activated potassium channel in basolateral membranes of rabbit colonocytes into planar lipid bilayers.
1989,
Pubmed
Wei,
Calcium sensitivity of BK-type KCa channels determined by a separable domain.
1994,
Pubmed
Weiss,
Voltage dependence and stability of the gating kinetics of the fast chloride channel from rat skeletal muscle.
1990,
Pubmed
White,
Selective interactions among the multiple connexin proteins expressed in the vertebrate lens: the second extracellular domain is a determinant of compatibility between connexins.
1994,
Pubmed
,
Xenbase
Whitfield,
Calcium-cell cycle regulator, differentiator, killer, chemopreventor, and maybe, tumor promoter.
1995,
Pubmed
Wiecha,
Blockade of Ca2+-activated K+ channels inhibits proliferation of human endothelial cells induced by basic fibroblast growth factor.
1998,
Pubmed
Xie,
Control of alternative splicing of potassium channels by stress hormones.
1998,
Pubmed
,
Xenbase
Zahradníková,
Single potassium channels of human glioma cells.
1992,
Pubmed
