Structural and Functional Assays of AtTLP18.3 Identify Its Novel Acid Phosphatase Activity in Thylakoid Lumen

Wu, Hsin‐Yi; Liu, Mao-Sen; Lin, Tsan-Piao; Cheng, Yi-Sheng

doi:10.1104/pp.111.184739

Cited by 45 publications

(46 citation statements)

References 53 publications

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“…Both are transmembrane auxiliary subunits associated with photosystem II (PSII). They are involved in PSII dimerization and removal of damaged D1 proteins 35,37 . AtTLP18.3 was recently suggested to possess an acid phosphatase activity 27 . It is unlikely that MOLO-1 serves a similar function in C. elegans, as the TPM domain of MOLO-1 is located in the extracellular space, whereas kinases and phosphatases function intracellularly.…”

Section: Conservation Of Tpm Domain-containing Proteinsmentioning

confidence: 99%

Positive modulation of a Cys-loop acetylcholine receptor by an auxiliary transmembrane subunit

et al. 2012

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Auxiliary subunits regulate the trafficking, localization or gating kinetics of voltage- and ligand-gated ion channels by associating tightly and specifically with pore-forming subunits. However, no auxiliary subunits have been identified for members of the Cys-loop receptor superfamily. Here we identify MOLO-1, a positive regulator of levamisole-sensitive acetylcholine receptors (L-AChRs) at the Caenorhabditis elegans neuromuscular junction. MOLO-1 is a one-pass transmembrane protein that contains a single extracellular globular domain-the TPM domain, found in bacteria, plants and invertebrates, including nonvertebrate chordates. Loss of MOLO-1 impairs locomotion and renders worms resistant to the anthelmintic drug levamisole. In molo-1 mutants, L-AChR-dependent synaptic transmission is reduced by half, while the number and localization of receptors at synapses remain unchanged. In a heterologous expression system, MOLO-1 physically interacts with L-AChRs and directly enhances channel gating without affecting unitary conductance. The identification of MOLO-1 expands the mechanisms for generating functional and pharmacological diversity in the Cys-loop superfamily.

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Section: Conservation Of Tpm Domain-containing Proteinsmentioning

confidence: 99%

Positive modulation of a Cys-loop acetylcholine receptor by an auxiliary transmembrane subunit

et al. 2012

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“…The optimal activity conditions of SSPP were determined as described previously (Wu et al, 2011) with some modifications. Briefly, to determine the optimal pH for SSPP activity, phosphatase activity assays were performed in 100 mM buffers, including sodium acetate buffer (pH 4.5 and 5.5), Tris/HCl buffer (pH 6.5-8.5), or Gly/NaOH buffer (pH 9.5 and 10.5), with 1 mg of purified SSPP protein and 7.5 mM pNPP (New England Biolabs), and the reactions were initiated by adding purified SSPP and incubated for 30 min at 47°C.…”

Section: Phosphatase Activity Assaymentioning

confidence: 99%

SENESCENCE-SUPPRESSED PROTEIN PHOSPHATASE Directly Interacts with the Cytoplasmic Domain of SENESCENCE-ASSOCIATED RECEPTOR-LIKE KINASE and Negatively Regulates Leaf Senescence in Arabidopsis

Xiao

Cui

et al. 2015

Plant Physiol.

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Reversible protein phosphorylation mediated by protein kinases and phosphatases plays an important role in the regulation of leaf senescence. We previously reported that the leucine-rich repeat receptor-like kinase SENESCENCE-ASSOCIATED RECEPTOR-LIKE KINASE (AtSARK) positively regulates leaf senescence in Arabidopsis (Arabidopsis thaliana). Here, we report the involvement of a protein serine/threonine phosphatase 2C-type protein phosphatase, SENESCENCE-SUPPRESSED PROTEIN PHOSPHATASE (SSPP), in the negative regulation of Arabidopsis leaf senescence. SSPP transcript levels decreased greatly during both natural senescence and SARK-induced precocious senescence. Overexpression of SSPP significantly delayed leaf senescence in Arabidopsis. Protein pull-down and bimolecular fluorescence complementation assays demonstrated that the cytosol-localized SSPP could interact with the cytoplasmic domain of the plasma membrane-localized AtSARK. In vitro assays showed that SSPP has protein phosphatase function and can dephosphorylate the cytosolic domain of AtSARK. Consistent with these observations, overexpression of SSPP effectively rescued AtSARK-induced precocious leaf senescence and changes in hormonal responses. All our results suggested that SSPP functions in sustaining proper leaf longevity and preventing early senescence by suppressing or perturbing SARK-mediated senescence signal transduction.

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“…In addition to proteolytic activity, Deg1 assists PSII assembly through interaction with the reaction center protein D2 (Sun et al, 2010b). Interestingly, the thylakoid lumen acidic phosphatase TLP18.3 is also involved in the degradation of D1 protein, but also in dimerization of PSII (Sirpio et al, 2007; Wu et al, 2011). Interaction between TLP18.3 and Deg1 (Zienkiewicz et al, 2012) might regulate the protease through dephosphorylation (Spetea and Lundin, 2012).…”

Section: The Psii Assembly and Repair Involve A Large Array Of Lumenamentioning

confidence: 99%

Understanding the roles of the thylakoid lumen in photosynthesis regulation

2013

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It has been known for a long time that the thylakoid lumen provides the environment for oxygen evolution, plastocyanin-mediated electron transfer, and photoprotection. More recently lumenal proteins have been revealed to play roles in numerous processes, most often linked with regulating thylakoid biogenesis and the activity and turnover of photosynthetic protein complexes, especially the photosystem II and NAD(P)H dehydrogenase-like complexes. Still, the functions of the majority of lumenal proteins in Arabidopsis thaliana are unknown. Interestingly, while the thylakoid lumen proteome of at least 80 proteins contains several large protein families, individual members of many protein families have highly divergent roles. This is indicative of evolutionary pressure leading to neofunctionalization of lumenal proteins, emphasizing the important role of the thylakoid lumen for photosynthetic electron transfer and ultimately for plant fitness. Furthermore, the involvement of anterograde and retrograde signaling networks that regulate the expression and activity of lumen proteins is increasingly pertinent. Recent studies have also highlighted the importance of thiol/disulfide modulation in controlling the functions of many lumenal proteins and photosynthetic regulation pathways.

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Structural and Functional Assays of AtTLP18.3 Identify Its Novel Acid Phosphatase Activity in Thylakoid Lumen

Cited by 45 publications

References 53 publications

Positive modulation of a Cys-loop acetylcholine receptor by an auxiliary transmembrane subunit

Positive modulation of a Cys-loop acetylcholine receptor by an auxiliary transmembrane subunit

SENESCENCE-SUPPRESSED PROTEIN PHOSPHATASE Directly Interacts with the Cytoplasmic Domain of SENESCENCE-ASSOCIATED RECEPTOR-LIKE KINASE and Negatively Regulates Leaf Senescence in Arabidopsis

Understanding the roles of the thylakoid lumen in photosynthesis regulation

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