title: Inositol trisphosphate modification of ion transport in rough endoplasmic reticulum.
abstract: The ion transport properties of the rough endoplasmic reticulum (RER) from liver have been defined by using measurements of active and potential gradient-driven transport. The Ca2+ pump is shown to be electrogenic, and both ATP and potential difference is able to drive vanadate-inhibitable Ca2+ uptake into the RER. ATP-dependent Ca2+ transport into the RER depends on the presence of tetraethylammonium-sensitive cation conductance and a furosemide-inhibited cation/chloride cotransport pathway. Inositol trisphosphate does not affect either of the monovalent ion translocation systems but activates a Ca2+ conductance in the RER, allowing efflux of RER Ca2+ stores into the cytosol in exchange for K+ uptake.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002586:Cesium / Q000494:pharmacology; D002712:Chlorides / Q000378:metabolism*; D004553:Electric Conductivity; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005665:Furosemide / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000378:metabolism*; D008099:Liver / Q000648:ultrastructure; D008564:Membrane Potentials; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D012413:Rubidium / Q000378:metabolism; D013403:Sugar Phosphates / Q000378:metabolism*; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
chemical_list: D002712:Chlorides; D007295:Inositol Phosphates; D013403:Sugar Phosphates; D013757:Tetraethylammonium Compounds; D002586:Cesium; D019789:Tetraethylammonium; D005665:Furosemide; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; C028019:cesium chloride; D012413:Rubidium; D011188:Potassium; D002118:Calcium