325 research outputs found
Serine and threonine residues of plant STN7 kinase are differentially phosphorylated upon changing light conditions and specifically influence the activity and stability of the kinase
STN7 kinase catalyzes the phosphorylation of the globally most common membrane proteins, the light-harvesting complex II (LHCII) in plant chloroplasts. STN7 itself possesses one serine (Ser) and two threonine (Thr) phosphosites. We show that phosphorylation of the Thr residues protects STN7 against degradation in darkness, low light and red light, whereas increasing light intensity and far red illumination decrease phosphorylation and induce STN7 degradation. Ser phosphorylation, in turn, occurs under red and low intensity white light, coinciding with the client protein (LHCII) phosphorylation. Through analysis of the counteracting LHCII phosphatase mutant tap38/pph1, we show that Ser phosphorylation and activation of the STN7 kinase for subsequent LHCII phosphorylation are heavily affected by pre-illumination conditions. Transitions between the three activity states of the STN7 kinase (deactivated in darkness and far red light, activated in low and red light, inhibited in high light) are shown to modulate the phosphorylation of the STN7 Ser and Thr residues independently of each other. Such dynamic regulation of STN7 kinase phosphorylation is crucial for plant growth and environmental acclimation
PSB33 protein sustains photosystem II in plant chloroplasts under UV-A light
Plants can quickly and dynamically respond to spectral and intensity variations of the incident light. These responses include activation of developmental processes, morphological changes, and photosynthetic acclimation that ensure optimal energy conversion and minimal photoinhibition. Plant adaptation and acclimation to environmental changes have been extensively studied, but many details surrounding these processes remain elusive. The photosystem II (PSII)-associated protein PSB33 plays a fundamental role in sustaining PSII as well as in the regulation of the light antenna in fluctuating light. We investigated how PSB33 knock-out Arabidopsis plants perform under different light qualities. psb33 plants displayed a reduction of 88% of total fresh weight compared to wild type plants when cultivated at the boundary of UV-A and blue light. The sensitivity towards UV-A light was associated with a lower abundance of PSII proteins, which reduces psb33 plants\u27 capacity for photosynthesis. The UV-A phenotype was found to be linked to altered phytohormone status and changed thylakoid ultrastructure. Our results collectively show that PSB33 is involved in a UV-A light-mediated mechanism to maintain a functional PSII pool in the chloroplast
PSB33 sustains photosystem II D1 protein under fluctuating light conditions
On Earth, solar irradiance varies as the sun rises and sets over the
horizon, and sunlight is thus in constant fluctuation, following a slow
dark–low–high–low–dark curve. Optimal plant growth and development are
dependent on the capacity of plants to acclimate and regulate
photosynthesis in response to these changes of light. Little is known of
regulative processes for photosynthesis during nocturnal events. The
nucleus-encoded plant lineage-specific protein PSB33 has been described
as stabilizing the photosystem II complex, especially under light stress
conditions, and plants lacking PSB33 have a dysfunctional state
transition. To clarify the localization and function of this protein, we
used phenomic, biochemical and proteomics approaches in the model plant
Arabidopsis. We report that PSB33 is predominantly located in
non-appressed thylakoid regions and dynamically associates with a
thylakoid protein complex in a light-dependent manner. Moreover, plants
lacking PSB33 show an accelerated D1 protein degradation in nocturnal
periods, and show severely stunted growth when challenged with
fluctuating light. We further show that the function of PSB33 precedes
the STN7 kinase to regulate or balance the excitation energy of
photosystems I and II in fluctuating light conditions.</p
Разработка инвестиционного проекта «Пасека» в развитии агротуризма
Материалы V Междунар. науч. конф. студентов, аспирантов и молодых ученых, Гомель, 24 мая 2012
Gut and liver T cells of common clonal origin are detected in primary sclerosing cholangitis-inflammatory bowel disease
Internet Ethics and Education in Japan
The First Conference on Human.Society@Internet(2001年7月4日, Seoul) Internet Ethics and ducaiton in Japan (Invited Talk)のスライ
PSB33 protein sustains Photosystem II in plant chloroplasts under UVA light
Plants can quickly and dynamically respond to spectral and intensity variations of the incident light. These responses include activation of developmental processes, morphological changes, and photosynthetic acclimation that ensure optimal energy conversion and minimal photoinhibition. Plant adaptation and acclimation to environmental changes have been extensively studied, but many details surrounding these processes remain elusive. The Photosystem II (PSII) associated protein PSB33 plays a fundamental role in sustaining PSII as well as in the regulation of the light antenna in fluctuating lights. We investigated how PSB33 knock-out plants perform under different light qualities. psb33 plants displayed 88% lower fresh weight compared to wild type plants when cultivated in the border of UVA-blue light. The sensitivity towards UVA light was associated with a lower abundance of PSII proteins, which reduces psb33 plants´ capacity for photosynthesis. The UVA phenotype was further found to be linked to altered phytohormone status and changed thylakoid ultrastructure. Our results collectively show that PSB33 is involved in a UVA light-mediated mechanism to maintain a functional PSII pool in the chloroplast
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