CALCIUM CALMODULIN-DEPENDENT AND CALCIUM/CALMODULIN-INDEPENDENT PHYTOCHROME SIGNAL-TRANSDUCTION PATHWAYS/

Citation
G. Neuhaus et al., CALCIUM CALMODULIN-DEPENDENT AND CALCIUM/CALMODULIN-INDEPENDENT PHYTOCHROME SIGNAL-TRANSDUCTION PATHWAYS/, Cell, 73(5), 1993, pp. 937-952
Citations number
51
Categorie Soggetti
Biology,"Cytology & Histology
Journal title
CellACNP
ISSN journal
00928674
Volume
73
Issue
5
Year of publication
1993
Pages
937 - 952
Database
ISI
SICI code
0092-8674(1993)73:5<937:CCACP>2.0.ZU;2-V
Abstract
Phytochrome is a well-characterized plant photoreceptor, able to modul ate many morphological, physiological, and biochemical events through as yet undefined mechanisms. By developing single-cell assays to visua lize phytochrome responses, we have studied the effects of microinject ing putative signaling intermediates into phytochrome-deficient tomato cells. We demonstrate that phytochrome phototransduction initially in volves the activation of one or more G proteins that are coupled to at least two different pathways; one pathway requires calcium and activa ted calmodulin and can stimulate expression of a photoregulated cab-GU S reporter gene together with the synthesis and assembly of some, but not all, of the photosynthetic complexes. The other pathway, controlli ng anthocyanin biosynthesis, does not require calcium. Furthermore, ou r results reveal that phytochrome signaling is cell autonomous and is not likely to require any light-activated steps downstream of the G pr otein.