title: GTP causes calcium release from a plant microsomal fraction.
abstract: Studies on a variety of animal cell types have revealed a GTP-specific calcium-releasing mechanism in a non-mitochondrial, microsomal fraction. Here we report that GTP also induces rapid release of calcium from a zucchini (Cucurbita pepo L.) hypocotyl microsomal fraction. Maximal release occurs at 50 microM, and half-maximal release at 8 microM GTP. GTP is highly specific in its effect, and may not be replaced by UTP, ATP, CTP, TTP, GMP, or by non-hydrolysable analogues of GTP. Reuptake of calcium after release does not normally occur; however, this may be induced by non-hydrolysable GTP analogues. Calcium release is also blocked by prior treatment with these analogues.
authors.affiliation: John Innes Institute, Norwich, England.
authors.forename: E
authors.initials: E
authors.lastname: Allan
authors.forename: A
authors.initials: A
authors.lastname: Dawson
authors.forename: B
authors.initials: B
authors.lastname: Drøbak
authors.forename: K
authors.initials: K
authors.lastname: Roberts
mesh_terms: D000255:Adenosine Triphosphate / Q000502:physiology; D002118:Calcium / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006153:Guanosine Diphosphate / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D008854:Microscopy, Electron; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D010944:Plants / Q000378:metabolism* / Q000648:ultrastructure; D011092:Polyethylene Glycols; D013873:Thionucleotides / Q000494:pharmacology
chemical_list: D013873:Thionucleotides; D006153:Guanosine Diphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D011092:Polyethylene Glycols; C004805:5'-guanylylmethylenebisphosphonate; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D002118:Calcium