Role of plastid protein phosphatase TAP38 in LHCII dephosphorylation and thylakoid electron flow
Articolo
Data di Pubblicazione:
2010
Citazione:
Role of plastid protein phosphatase TAP38 in LHCII dephosphorylation and thylakoid electron flow / M. Pribil, P. Pesaresi, A. Hertle, R. Barbato, D. Leister. - In: PLOS BIOLOGY. - ISSN 1544-9173. - 8:1(2010), pp. e1000288.e1000288.1-e1000288.e1000288.12.
Abstract:
Short-term changes in illumination elicit alterations in thylakoid protein phosphorylation and reorganization of the
photosynthetic machinery. Phosphorylation of LHCII, the light-harvesting complex of photosystem II, facilitates its
relocation to photosystem I and permits excitation energy redistribution between the photosystems (state transitions). The
protein kinase STN7 is required for LHCII phosphorylation and state transitions in the flowering plant Arabidopsis thaliana.
LHCII phosphorylation is reversible, but extensive efforts to identify the protein phosphatase(s) that dephosphorylate LHCII
have been unsuccessful. Here, we show that the thylakoid-associated phosphatase TAP38 is required for LHCII
dephosphorylation and for the transition from state 2 to state 1 in A. thaliana. In tap38 mutants, thylakoid electron flow is
enhanced, resulting in more rapid growth under constant low-light regimes. TAP38 gene overexpression markedly
decreases LHCII phosphorylation and inhibits state 1R2 transition, thus mimicking the stn7 phenotype. Furthermore, the
recombinant TAP38 protein is able, in an in vitro assay, to directly dephosphorylate LHCII. The dependence of LHCII
dephosphorylation upon TAP38 dosage, together with the in vitro TAP38-mediated dephosphorylation of LHCII, suggests
that TAP38 directly acts on LHCII. Although reversible phosphorylation of LHCII and state transitions are crucial for plant
fitness under natural light conditions, LHCII hyperphosphorylation associated with an arrest of photosynthesis in state 2 due
to inactivation of TAP38 improves photosynthetic performance and plant growth under state 2-favoring light conditions.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Thylakoid ; Phosphatase ; Light ; Acclimation
Elenco autori:
M. Pribil, P. Pesaresi, A. Hertle, R. Barbato, D. Leister
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