title: Phytochrome regulates GTP-binding protein activity in the envelope of pea nuclei.
abstract: 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.
authors.affiliation: Department of Botany, University of Texas, Austin 78713, USA.
authors.forename: G B
authors.initials: GB
authors.lastname: Clark
authors.forename: A R
authors.initials: AR
authors.lastname: Memon
authors.lastname: Tong C-G
authors.forename: G A
authors.initials: GA
authors.lastname: Thompson
authors.forename: S J
authors.initials: SJ
authors.lastname: Roux
mesh_terms: 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
chemical_list: D010761:Phosphorus Radioisotopes; D010834:Phytochrome; D019204:GTP-Binding Proteins