The 9-kDa phosphoprotein of photosystem

O’Connor, Helen E.; Ruffle, Stuart V.; Cain, Amanda J; Deák, Zsuzsanna; Vass, Imre; Nugent, Jonathan H. A.; Purton, Saul

doi:10.1016/s0005-2728(98)00013-9

Cited by 44 publications

(14 citation statements)

References 41 publications

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“…In contrast to phosphorylation at Thr-2, modification of Thr-4 is highly sensitive to the ambient light conditions, being rapidly dephosphorylated when plants are placed in darkness. In the green alga Chlamydomonas reinhardtii, PsbH is essential for assembling PSII in thylakoids (36); psbH mutants have a PSII-deficient phenotype and lack a functional PSII complex (36,37). O'Connor et al (37) concluded from studies showing that C. reinhardtii strains expressing a PsbH mutant lacking Thr-2 (Thr-2 to Ala) behave as wild-type, that phosphorylation of PsbH may not be important for its function.…”

Section: Resultsmentioning

confidence: 99%

“…In the green alga Chlamydomonas reinhardtii, PsbH is essential for assembling PSII in thylakoids (36); psbH mutants have a PSII-deficient phenotype and lack a functional PSII complex (36,37). O'Connor et al (37) concluded from studies showing that C. reinhardtii strains expressing a PsbH mutant lacking Thr-2 (Thr-2 to Ala) behave as wild-type, that phosphorylation of PsbH may not be important for its function. However, our finding of a second phosphorylation site in PsbH and the demonstration that modification of this site is light responsive in vivo reopens the role of phosphorylation in PsbH function.…”

Section: Resultsmentioning

confidence: 99%

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Mass Spectrometric Resolution of Reversible Protein Phosphorylation in Photosynthetic Membranes ofArabidopsis thaliana

Vener¹,

Harms

Sussman

et al. 2001

Journal of Biological Chemistry

192

210

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The use of mass spectrometry to characterize the phosphorylome, i.e. the constituents of the proteome that become phosphorylated, was demonstrated using the reversible phosphorylation of chloroplast thylakoid proteins as an example. From the analysis of tryptic peptides released from the surface of Arabidopsis thylakoids, the principal phosphoproteins were identified by matrix-assisted laser desorption/ionization and electrospray ionization mass spectrometry. These studies revealed that the D1, D2, and CP43 proteins of the photosystem II core are phosphorylated at their N-terminal threonines (Thr), the peripheral PsbH protein is phosphorylated at Thr-2, and the mature light-harvesting polypeptides LCHII are phosphorylated at Thr-3. In addition, a doubly phosphorylated form of PsbH modified at both Thr-2 and Thr-4 was detected. By comparing the levels of phospho-and nonphosphopeptides, the in vivo phosphorylation states of these proteins were analyzed under different physiological conditions. None of these thylakoid proteins were completely phosphorylated in the steady state conditions of continuous light or completely dephosphorylated after a long dark adaptation. However, rapid reversible hyperphosphorylation of PsbH at Thr-4 in response to growth in light/dark transitions and a pronounced specific dephosphorylation of the D1, D2, and CP43 proteins during heat shock was detected. Collectively, our data indicate that changes in the phosphorylation of photosynthetic proteins are more rapid during heat stress than during normal light/ dark transitions. These mass spectrometry methods offer a new approach to assess the stoichiometry of in vivo protein phosphorylation in complex samples.The reversible phosphorylation of specific proteins participates in the regulation of virtually all aspects of cell physiology and development. The extent of its importance is illustrated by the hundreds of conventional protein kinases and phosphatases detected in various eukaryotic genomes (1-3). Whereas, serine, threonine, and tyrosine residues are the typical targets of these kinases, phosphorylation of at least six other amino acids is feasible, potentially expanding even further the dimensions of this post-translational modification (reviewed in Ref. 4). Despite the importance of this pool of phosphorylated proteins, our understanding of its depth and breadth remains sketchy. One barrier has been the lack of methods to define en masse the "phosphorylome," i.e. the subset of proteins in the proteome that become modified in vivo by phosphorylation. Precise characterization of the phosphorylome will be essential to fully understand how proteins are activated or inhibited, encouraged to interact with other components in the cell, and selected for rapid degradation. Certainly, the dynamic and transient nature of many protein phosphorylation reactions underscores the difficulties of resolving the complete phosphorylome for a given organism. Nevertheless, the identification of even just the principal cellular phosphoproteins under dis...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Mass Spectrometric Resolution of Reversible Protein Phosphorylation in Photosynthetic Membranes ofArabidopsis thaliana

Vener¹,

Harms

Sussman

et al. 2001

Journal of Biological Chemistry

192

210

View full text Add to dashboard Cite

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“…Interestingly, we also found T8 phosphorylation of PsbH was decreased upon palmella formation (Figure 9C and Table 3). However, a T2 knockdown mutant of PsbH in C. reinhardtii has similar phonotype of wild-type strains, indicating that T2 phosphorylation of PsbH probably doesn't affect its function (O'Connor et al, 1998). Besides, PSII protein VI is the beta subunit of cytochrome b559 essential for PSII assembly, whose increase would enhance the cyclic electron transport (CET) or in a side path of electron flow for protecting PSII from photoinhibition (Figure 9C and Table 1; Burda et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

Salinity-Induced Palmella Formation Mechanism in Halotolerant Algae Dunaliella salina Revealed by Quantitative Proteomics and Phosphoproteomics

et al. 2017

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Palmella stage is critical for some unicellular algae to survive in extreme environments. The halotolerant algae Dunaliella salina is a good single-cell model for studying plant adaptation to high salinity. To investigate the molecular adaptation mechanism in salinity shock-induced palmella formation, we performed a comprehensive physiological, proteomics and phosphoproteomics study upon palmella formation of D. salina using dimethyl labeling and Ti4+-immobilized metal ion affinity chromatography (IMAC) proteomic approaches. We found that 151 salinity-responsive proteins and 35 salinity-responsive phosphoproteins were involved in multiple signaling and metabolic pathways upon palmella formation. Taken together with photosynthetic parameters and enzyme activity analyses, the patterns of protein accumulation and phosphorylation level exhibited the mechanisms upon palmella formation, including dynamics of cytoskeleton and cell membrane curvature, accumulation and transport of exopolysaccharides, photosynthesis and energy supplying (i.e., photosystem II stability and activity, cyclic electron transport, and C4 pathway), nuclear/chloroplastic gene expression regulation and protein processing, reactive oxygen species homeostasis, and salt signaling transduction. The salinity-responsive protein–protein interaction (PPI) networks implied that signaling and protein synthesis and fate are crucial for modulation of these processes. Importantly, the 3D structure of phosphoprotein clearly indicated that the phosphorylation sites of eight proteins were localized in the region of function domain.

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“…In higher plants and algae, it is also the region on the PsbH protein where reversible N-terminal phosphorylation occurs (47). Also of note is that the deletion of the psbH gene from Chlamydomonas reinhardtii inhibited the accumulation of PSII in the membrane (48,49) and led Summers et al (48) to conclude that perhaps the primary role of the PsbH protein was to facilitate PSII assembly/stability. Furthermore, according to the current structural model of PSII shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

Phosphatidylglycerol Is Involved in the Dimerization of Photosystem II

Kruse

Hankamer

Konczak

et al. 2000

Journal of Biological Chemistry

160

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Photosystem II core dimers (450 kDa) and monomers (230 kDa) consisting of CP47, CP43, the D1 and D2 proteins, the extrinsic 33-kDa subunit, and the low molecular weight polypeptides PsbE, PsbF, PsbH, PsbI, PsbK, PsbL, PsbTc, and PsbW were isolated by sucrose density gradient centrifugation. The photosystem II core dimers were treated with phospholipase A2 (PL-A2), which cuts phosphatidylglycerol (PG) and phosphatidylcholine molecules at the sn-2 position. The PL-A2-treated dimers dissociated into two core monomers and further, yielding a CP47-D1-D2 subcomplex and CP43. Thin layer chromatography showed that photosystem II dimers contained four times more PG than their monomeric counterparts but with similar levels of phosphatidylcholine. Consistent with this was the finding that, compared with monomers, the dimers contained a higher level of trans-hexadecanoic fatty acid (C16:1⌬3tr), which is specific to PG of the thylakoid membrane. Moreover, treatment of dimers with PL-A2 increased the free level of this fatty acid specific to PG compared with untreated dimers. Further evidence that PG is involved in stabilizing the dimeric state of photosystem II comes from reconstitution experiments. Using size exclusion chromatography, it was shown that PG containing C16:1⌬3tr, but not other lipid classes, induced significant dimerization of isolated photosystem II monomers. Moreover, this dimerization was observed by electron crystallography when monomers were reconstituted into thylakoid lipids containing PG. The unit cell parameters, p2 symmetry axis, and projection map of the reconstituted dimer was similar to that observed for two-dimensional crystals of the native dimer.

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The 9-kDa phosphoprotein of photosystem

Cited by 44 publications

References 41 publications

Mass Spectrometric Resolution of Reversible Protein Phosphorylation in Photosynthetic Membranes ofArabidopsis thaliana

Mass Spectrometric Resolution of Reversible Protein Phosphorylation in Photosynthetic Membranes ofArabidopsis thaliana

Salinity-Induced Palmella Formation Mechanism in Halotolerant Algae Dunaliella salina Revealed by Quantitative Proteomics and Phosphoproteomics

Phosphatidylglycerol Is Involved in the Dimerization of Photosystem II

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