GTP causes calcium release from a plant microsomal fraction.
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.
Allan
E
E
John Innes Institute, Norwich, England.
Dawson
A
A
Drøbak
B
B
Roberts
K
K
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
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