BIOMAT Database Logo BIOMAT Database Logo

Endothelial K(+) channel lacks the Ca(2+) sensitivity-regulating beta subunit. 2000

J Papassotiriou, and R Köhler, and J Prenen, and H Krause, and M Akbar, and J Eggermont, and M Paul, and A Distler, and B Nilius, and J Hoyer
Abteilung für Nephrologie, Abteilung für Urologie, Institut für Klinische Pharmakologie, UKBF, Freie Universität Berlin, Germany.

Hyperpolarizing large-conductance, Ca(2+)-activated K(+) channels (BK) are important modulators of vascular smooth muscle and endothelial cell function. In vascular smooth muscle cells, BK are composed of pore-forming alpha subunits and modulatory beta subunits. However, expression, composition, and function of BK subunits in endothelium have not been studied so far. In patch-clamp experiments we identified BK (283 pS) in intact endothelium of porcine aortic tissue slices. The BK opener DHS-I (0.05-0.3 micromol/l), stimulating BK activity only in the presence of beta subunits, had no effect on BK in endothelium whereas the alpha subunit selective BK opener NS1619 (20 micromol/l) markedly increased channel activity. Correspondingly, mRNA expression of the beta subunit was undetectable in endothelium, whereas alpha subunit expression was demonstrated. To investigate the functional role of beta subunits, we transfected the beta subunit into a human endothelial cell line (EA.hy 926). beta subunit expression resulted in an increased Ca(2+) sensitivity of BK activity: the potential of half-maximal activation (V(1/2)) shifted from 73.4 mV to 49.6 mV at 1 micromol/l [Ca(2+)](i) and an decrease of the EC(50) value for [Ca(2+)](i) by 1 microM at +60 mV was observed. This study demonstrates that BK channels in endothelium are composed of alpha subunits without association to beta subunits. The lack of the beta subunit indicates a substantially different channel regulation in endothelial cells compared to vascular smooth muscle cells.

UI MeSH Term Description Entries
D002118 Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002478 Cells, Cultured Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others. Cultured Cells,Cell, Cultured,Cultured Cell
D004730 Endothelium, Vascular Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components. Capillary Endothelium,Vascular Endothelium,Capillary Endotheliums,Endothelium, Capillary,Endotheliums, Capillary,Endotheliums, Vascular,Vascular Endotheliums
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D001483 Base Sequence The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence. DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D013552 Swine Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA). Phacochoerus,Pigs,Suidae,Warthogs,Wart Hogs,Hog, Wart,Hogs, Wart,Wart Hog
D014162 Transfection The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES. Transfections
D015221 Potassium Channels Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits. Ion Channels, Potassium,Ion Channel, Potassium,Potassium Channel,Potassium Ion Channels,Channel, Potassium,Channel, Potassium Ion,Channels, Potassium,Channels, Potassium Ion,Potassium Ion Channel
D017931 DNA Primers Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques. DNA Primer,Oligodeoxyribonucleotide Primer,Oligodeoxyribonucleotide Primers,Oligonucleotide Primer,Oligonucleotide Primers,Primer, DNA,Primer, Oligodeoxyribonucleotide,Primer, Oligonucleotide,Primers, DNA,Primers, Oligodeoxyribonucleotide,Primers, Oligonucleotide

Related Publications

J Papassotiriou, and R Köhler, and J Prenen, and H Krause, and M Akbar, and J Eggermont, and M Paul, and A Distler, and B Nilius, and J Hoyer
Functional coupling of the beta(1) subunit to the large conductance Ca(2+)-activated K(+) channel in the absence of Ca(2+). Increased Ca(2+) sensitivity from a Ca(2+)-independent mechanism.
June 2000, The Journal of general physiology,
J Papassotiriou, and R Köhler, and J Prenen, and H Krause, and M Akbar, and J Eggermont, and M Paul, and A Distler, and B Nilius, and J Hoyer
Creation by mutagenesis of a mammalian Ca(2+) channel beta subunit that confers praziquantel sensitivity to a mammalian Ca(2+) channel.
October 2003, International journal for parasitology,
J Papassotiriou, and R Köhler, and J Prenen, and H Krause, and M Akbar, and J Eggermont, and M Paul, and A Distler, and B Nilius, and J Hoyer
Role of the beta1 subunit in large-conductance Ca(2+)-activated K(+) channel gating energetics. Mechanisms of enhanced Ca(2+) sensitivity.
September 2000, The Journal of general physiology,
J Papassotiriou, and R Köhler, and J Prenen, and H Krause, and M Akbar, and J Eggermont, and M Paul, and A Distler, and B Nilius, and J Hoyer
Cloning, expression, and distribution of a Ca(2+)-activated K+ channel beta-subunit from human brain.
August 1996, Proceedings of the National Academy of Sciences of the United States of America,
J Papassotiriou, and R Köhler, and J Prenen, and H Krause, and M Akbar, and J Eggermont, and M Paul, and A Distler, and B Nilius, and J Hoyer
Reversibility of the Ca(2+) channel alpha(1)-beta subunit interaction.
November 2000, Biochemical and biophysical research communications,
J Papassotiriou, and R Köhler, and J Prenen, and H Krause, and M Akbar, and J Eggermont, and M Paul, and A Distler, and B Nilius, and J Hoyer
Genetic analysis of the mammalian K+ channel beta subunit Kvbeta 2 (Kcnab2).
April 2002, The Journal of biological chemistry,
J Papassotiriou, and R Köhler, and J Prenen, and H Krause, and M Akbar, and J Eggermont, and M Paul, and A Distler, and B Nilius, and J Hoyer
Primary sequence and immunological characterization of beta-subunit of high conductance Ca(2+)-activated K+ channel from smooth muscle.
June 1994, The Journal of biological chemistry,
J Papassotiriou, and R Köhler, and J Prenen, and H Krause, and M Akbar, and J Eggermont, and M Paul, and A Distler, and B Nilius, and J Hoyer
Kinetic modification of the alpha(1I) subunit-mediated T-type Ca(2+) channel by a human neuronal Ca(2+) channel gamma subunit.
June 2001, The Journal of physiology,
J Papassotiriou, and R Köhler, and J Prenen, and H Krause, and M Akbar, and J Eggermont, and M Paul, and A Distler, and B Nilius, and J Hoyer
Functional effects of auxiliary beta4-subunit on rat large-conductance Ca(2+)-activated K(+) channel.
May 2004, Biophysical journal,
J Papassotiriou, and R Köhler, and J Prenen, and H Krause, and M Akbar, and J Eggermont, and M Paul, and A Distler, and B Nilius, and J Hoyer
Wanderlust kinetics and variable Ca(2+)-sensitivity of Drosophila, a large conductance Ca(2+)-activated K+ channel, expressed in oocytes.
June 1996, Biophysical journal,
Copied contents to your clipboard!