PKS1, a Substrate Phosphorylated by Phytochrome That Modulates Light Signaling in
            <i>Arabidopsis</i>

Fankhauser, Christian; Yeh, Kuo‐Chen; Clark, Jennifer A.; Lagarias, J. Clark; Zhang, Hong; Elich, Tedd D.; Chory, Joanne

doi:10.1126/science.284.5419.1539

Cited by 402 publications

(329 citation statements)

References 31 publications

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“…Mutually regulated regulators PHYTOCHROME KINASE SUBSTRATE 1 (PKS1, Accession number AF149053) is phosphorylated by phyA [51]. The expression of PKS1 and of PKS2 (Accession number NM101294, the closest homologue of PKS1 in the Arabidopsis genome) is rapidly and transiently enhanced by light perceived by phyA [52].…”

Section: Regulatory Loopsmentioning

confidence: 99%

Signalling for developmental plasticity

Casal

Fankhauser²,

Coupland

et al. 2004

Trends in Plant Science

119

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Section: Regulatory Loopsmentioning

confidence: 99%

Signalling for developmental plasticity

Casal

Fankhauser²,

Coupland

et al. 2004

Trends in Plant Science

119

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“…One such protein, PKS1 (for phytochrome kinase substrate 1), which binds to both PhyA and PhyB, is a kinase substrate phosphorylated in a phytochrome-dependent manner, which is supposed to be a negative regulator of PhyB signaling. PKS1-GFP fusion proteins are cytoplasmic (Fankhauser et al, 1999). Another molecule, PIF3 (for phytochrome-interacting factor 3), which also binds to both PhyA and PhyB, is a basic helix-loophelix protein and potential transcriptional regulator; it is indispensable for normal signal transduction of phytochrome.…”

Section: Light-regulated Nuclear Import Of Phytochromesmentioning

confidence: 99%

Light-Induced Nuclear Translocation of Endogenous Pea Phytochrome A Visualized by Immunocytochemical Procedures

et al. 2000

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Although the physiological functions of phytochrome A (PhyA) are now known, the distribution of endogenous PhyA has not been examined. We have visualized endogenous PhyA apoprotein (PHYA) by immunolabeling cryosections of pea tissue, using PHYA-deficient mutants as negative controls. By this method, we examined the distribution of PHYA in different tissues and changes in its intracellular distribution in response to light. In apical hook cells of etiolated seedlings, PHYA immunolabeling was distributed diffusely in the cytosol. Exposure to continuous far-red (cFR) light caused a redistribution of the immunolabeling to the nucleus, first detectable after 1.5 hr and greatest at 4.5 hr. During this time, the amounts of spectrally active phytochrome and PHYA did not decline substantially. Exposure to continuous red (cR) light or to a brief pulse of red light also resulted in redistribution of immunolabeling to the nucleus, but this occurred much more rapidly and with a different pattern of intranuclear distribution than it did in response to cFR light. Exposures to cR light resulted in loss of immunolabeling, which was associated with PHYA degradation. These results indicate that the light-induced intracellular location of PHYA is wavelength dependent and imply that this is important for PhyA activity. INTRODUCTIONThe phytochrome family of plant photoreceptors regulates various molecular and cellular processes of plant development in response to the light environment . Phytochromes are soluble chromoproteins that convert photoreversibly between two spectrally distinct forms when sequentially absorbing red (R) and far-red (FR) light, and this interconversion occurs immediately both in vivo and in vitro (Butler et al., 1959). Phytochromes are encoded by a small gene family (phytochrome genes PHYA to PHYE in Arabidopsis; Sharrock and Quail, 1989;Clack et al., 1994). Studies with mutants deficient in specific phytochromes have shown that phytochrome A (PhyA) and phytochrome B (PhyB) have distinct action spectra for the photoinduction of seed germination (Shinomura et al., 1996) and distinct fluence and wavelength requirements for expression of the chlorophyll a / b binding protein gene ( CAB ) (Hamazato et al., 1997). The fundamental molecular basis for these differences is of great interest but has not been elucidated. Recent genetic and molecular analyses have defined differences in PhyA and PhyB activities with respect to interacting factors and signaling intermediates. Those studies suggest that PhyA and PhyB signals are transduced by overlapping signal transduction pathways (Deng and Quail, 1999).To complement such approaches, one must also consider the ways in which the concentration, photochemical activity, and localization of each phytochrome are regulated in tissues and cells (Pratt, 1994). In tissues, this regulation may affect the transmission of the light signal from the site of photoperception to the responsive organ. An analysis of the way in which photoreceptors are redistributed within the cell in respon...

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“…Phytochrome A (phyA) is the photoreceptor for far-red light and phytochrome B (phyB) is the major photoreceptor sensing red light (Deng and Quail, 1999;Neff et al, 2000). phyA is able to autophosphorylate and to phosphorylate phytochrome kinase substrate 1 (PKS1) in vitro (Yeh and Lagarias, 1998;Fankhauser et al, 1999). Both phyA and phyB translocate to the nucleus in response to red or far-red light signals (Kircher et al, 1999;Yamaguchi et al, 1999).…”

Section: Introductionmentioning

confidence: 99%