Phytochrome regulates GTP-binding protein activity in the envelope of pea nuclei.
Three GTP-binding proteins with apparent molecular masses of 27, 28 and 30 kDa have been detected in isolated nuclei of etiolated pea plumules.  After LDS-PAGE and transfer to nitrocellulose these proteins bind [32P]GTP in the presence of excess ATP, suggesting that they are monomeric G proteins.  When nuclei are disrupted, three proteins co-purify with the nuclear envelope fraction and are highly enriched in this fraction.  The level of [32P]GTP-binding for all three protein bands is significantly increased when harvested pea plumules are irradiated by red light, and this effect is reversed by far-red light.  The results indicate that GTP-binding activity associated with the nuclear envelope of plant cells is photoreversibly regulated by the pigment phytochrome.
Clark
G B
GB
Department of Botany, University of Texas, Austin 78713, USA.
Memon
A R
AR
Tong C-G
Thompson
G A
GA
Roux
S J
SJ
D002467:Cell Nucleus / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism* / Q000502:physiology*; D008027:Light; D018532:Pisum sativum / Q000166:cytology / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D010834:Phytochrome / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
D010761:Phosphorus Radioisotopes; D010834:Phytochrome; D019204:GTP-Binding Proteins