Biomaterial Database

Ion-transporting ATPases as ion channels. 1998

G Scheiner-Bobis

Institut für Biochemie und Endokrinologie, Fachbereich Veterinärmedizin, Justus-Liebig-Universität Giessen, Germany.

Ion-transporting ATPases (pumps) hydrolyze ATP to maintain ion gradients across cell membranes. A presupposition for the maintenance of the gradients is that the ionophore of the pump that conducts the ions is accessible only from one of the two surfaces of the plasma membrane at any given time. Thus, a characteristic feature of pumps is an occluded state of the transported ions, whereas ion channels upon stimulation remain open at both ends and allow ions to flow through them down their chemical gradients. Recent experiments, however, provide evidence that a channel, simultaneously open on both sides of the plasma membrane, can also be formed within the mammalian sodium pump (Na+,K+-ATPase) upon its interaction with the marine toxin palytoxin, thus underlining common structural features shared by channels and pumps. This assumption is further supported by the demonstration of structural and functional homology between the extracellular loop of the sodium pump alpha subunit connecting the M7 and M8 transmembrane spans and the P-loops of Na+ channels. Possibly, pumps are simply channels that are able to be gated by ATP and its product phosphate.

UI	MeSH Term	Description	Entries
D007473	Ion Channels	Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.	Membrane Channels,Ion Channel,Ionic Channel,Ionic Channels,Membrane Channel,Channel, Ion,Channel, Ionic,Channel, Membrane,Channels, Ion,Channels, Ionic,Channels, Membrane
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D003064	Cnidarian Venoms	Venoms from jellyfish; CORALS; SEA ANEMONES; etc. They contain hemo-, cardio-, dermo- , and neuro-toxic substances and probably ENZYMES. They include palytoxin, sarcophine, and anthopleurine.	Chironex Venoms,Jellyfish Venoms,Nematocyst Venoms,Sea Anemone Venoms,Chironex Venom,Cnidarian Venom,Jellyfish Venom,Portuguese Man-of-War Venom,Sea Anemone Venom,Portuguese Man of War Venom,Venom, Chironex,Venom, Cnidarian,Venom, Jellyfish,Venom, Portuguese Man-of-War,Venom, Sea Anemone,Venoms, Chironex,Venoms, Cnidarian,Venoms, Jellyfish,Venoms, Nematocyst,Venoms, Sea Anemone
D004553	Electric Conductivity	The ability of a substrate to allow the passage of ELECTRONS.	Electrical Conductivity,Conductivity, Electric,Conductivity, Electrical
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006868	Hydrolysis	The process of cleaving a chemical compound by the addition of a molecule of water.
D000178	Acrylamides	Colorless, odorless crystals that are used extensively in research laboratories for the preparation of polyacrylamide gels for electrophoresis and in organic synthesis, and polymerization. Some of its polymers are used in sewage and wastewater treatment, permanent press fabrics, and as soil conditioning agents.
D000254	Sodium-Potassium-Exchanging ATPase	An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.	ATPase, Sodium, Potassium,Adenosinetriphosphatase, Sodium, Potassium,Na(+)-K(+)-Exchanging ATPase,Na(+)-K(+)-Transporting ATPase,Potassium Pump,Sodium Pump,Sodium, Potassium ATPase,Sodium, Potassium Adenosinetriphosphatase,Sodium-Potassium Pump,Adenosine Triphosphatase, Sodium, Potassium,Na(+) K(+)-Transporting ATPase,Sodium, Potassium Adenosine Triphosphatase,ATPase Sodium, Potassium,ATPase, Sodium-Potassium-Exchanging,Adenosinetriphosphatase Sodium, Potassium,Pump, Potassium,Pump, Sodium,Pump, Sodium-Potassium,Sodium Potassium Exchanging ATPase,Sodium Potassium Pump
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
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