Differential Changes in the Amount of Protein Complexes in the Chloroplast Membrane during Senescence of Oat and Bean Leaves

Ben-David, Hilla; Nelson, Nathan; Gepstein, Shimon

doi:10.1104/pp.73.2.507

Cited by 54 publications

(27 citation statements)

References 12 publications

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“…2 Present address: POVAR-CNRS, 4 ter Rte des Gardes, 92190 Meudon, France. in gene expression. In particular, there is a selective depletion reflecting curtailed synthesis of Cytsfand b6 from the thylakoids of senescing leaves (3,25). This correlates with independent biochemical measurements showing that transport of electrons through the Cyt f/b6 complex is the rate-limiting step accounting for the decline in noncyclic electron transport (12,14).…”

mentioning

confidence: 52%

Active Translation of the D-1 Protein of Photosystem II in Senescing Leaves

Droillard¹,

Bate²,

Rothstein³

et al. 1992

Plant Physiol.

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ABSTRACTin gene expression. In particular, there is a selective depletion reflecting curtailed synthesis of Cytsfand b6 from the thylakoids of senescing leaves (3,25). This correlates with independent biochemical measurements showing that transport of electrons through the Cyt f/b6 complex is the rate-limiting step accounting for the decline in noncyclic electron transport (12,14). Indeed, the decline in noncyclic electron transport with advancing senescence is much more marked than the decline in the independent activities of PSI and PSII (14,22).Changes in thylakoid protein synthesis with advancing senescence have also been demonstrated by pulse labeling with [35S]methionine. Of particular interest is the finding that, whereas synthesis of the majority of thylakoid-associated photosynthetic proteins, including the 68-kD apoprotein of PSI, the a and : subunits of ATPase, light-harvesting Chl binding protein, and Cytsfand b6, decline by two-and fourfold during senescence, there is no decrease in synthesis of the D-1 protein of PSII (25). This does not, however, result in significant changes in steady-state levels of these proteins in the thylakoids of senescent leaves (25), presumably because, with the exception of D-1, thylakoid proteins generally have long halflives. There are also senescence-related changes in transcript levels for these proteins, although the differential changes in protein synthesis cannot be fully accounted for by alteration in steady-state message levels (1, 2).The finding that D-1 continues to be strongly synthesized in senescing leaves well after a sharp decline in the synthesis of other thylakoid photosynthetic proteins may be related to its comparatively short half-life and the need to maintain functional D-1 even under conditions of greatly reduced photosynthetic electron transport. The turnover of D-1 is very rapid, light-dependent, and inhibited by herbicides such as DCMU and atrazine that displace the second electron-accepting plastoquinone of PSII (20,28). This rapid turnover has been correlated with the presence of a 14-amino acid a helix in the protein, termed a destabilizing sequence, that is located adjacent to the putative cleavage domain (1 1). Recent data obtained with radical scavengers suggest that light-dependent D-1 degradation is initiated by activated oxygen, likely the hydroxyl radical, which causes it to undergo a change in conformation (26).Previous pulse/chase labeling studies have indicated that the turnover rate for D-1 does not change with advancing senscence (25), which suggests that the capability for generating activated oxygen may be retained in the senescing chloroplast notwithstanding a decline by more than 40% in 589 www.plantphysiol.org on May 9, 2018 -Published by Downloaded from

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mentioning

confidence: 52%

Active Translation of the D-1 Protein of Photosystem II in Senescing Leaves

Droillard¹,

Bate²,

Rothstein³

et al. 1992

Plant Physiol.

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“…protein complements of PS II and the cytoPhaeophorbide & is not a substrate for PhaO. And chrome 6//complexes are particularly labile during yet chlorophyll 6 is clearly broken down in sen-senescence (Ben-David, Nelson & Gepstein, 1983; escence: how? Recently Japanese workers have Holloway, Maclean & Scott, 1983; Woolhouse & described the conversion of chlorophyll 6 to a in Jenkins 1983; Roberts e/f a/., 1987) but under normal developing plastids (Itoh e^ a/., 1994; Itoh, Ohtsuka circumstances components of different complexes & Tanaka, 1996;Ohtsuka, Itoh & Tanaka, 1997).…”

Section: Subcellular Organization Of Chlorophyll Catabolismmentioning

confidence: 99%

Chlorophyll: a symptom and a regulator of plastid development

Thomas

1997

New Phytologist

103

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SUMMARY The metabolism of chlorophylls and related tetrapyrroles directly influences, and is influenced by, the proteins and cell structures with which they are associated. During net accumulation, de‐greening and at the steady state chlorophyll and its derivatives are important elements in the post‐translational regulation of the expression of genes for chloroplast proteins. At the same time, they represent potential photodynamic hazards against which green cells need to have protective mechanisms. This review deals with genetic, chemical and environmental perturbations of chlorophyll biosynthesis that impact on protein stability, membrane organization and susceptibility to photodamage. NADPH‐protochlorophyllide oxidoreductase is considered in detail as a pigment– protein regulating, and regulated by, chlorophyll metabolism. The question of the extent and significance of chlorophyll turnover at the steady state is addressed, with particular emphasis on the dynamics of the photosystem II reaction centre. The pathway of chlorophyll catabolism is described, along with its interrelationship with protein mobilization in chloroplast senescence. Finally, the structural basis of pigment‐protein interaction and stability is examined, and the discussion ends by expressing some general thoughts about the control of protein lifetimes in the living cell.

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“…This was attributed to a decrease in the usable level of cytochrome//ig in oat and bean leaves (Ben-David, Nelson & Gepstein, 1983) and barley leaves (Holloway, MacClean & Scott, 1983). Roberts et al (1987) used Western blot analysis to show that Cytochrome/ and b^ were selectively lost from thylakoids of bean leaves during senescence.…”

Section: Turnover During Senescencementioning

confidence: 99%

Proteolytic activity during senescence of plants

Huffaker

1990

New Phytologist

155

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summary Although information has rapidly developed concerning the intracellular localization of plant proteins, relatively few reports concern the intracellular location of endo‐ and exo‐proteolytic activities. Relatively few proteases have been purified, characterized, and associated with a specific cellular location. With the exception of the processing proteases involved in transport of proteins across membranes, little progress has yet been made concerning determination of in vivo products of specific proteases. Information on the turnover of individual proteins and the assessment of rate‐limiting steps in pathways as proteins are turned over is steadily appearing. Since chloroplasts are the major site of both protein synthesis and, during senescence, degradation, it was important to show unambiguously that chloroplasts can degrade their own constituents. Another important contribution was to obtain evidence that the chloroplasts contain proteases capable of degrading their constituents. This work has been more tenuous because of the low activities found and the possibility of contamination by vacuolar enzymes during the isolation of organelles. The possible targeting of cytoplasmic proteins for degradation by facilitating their transport into vacuoles is a field which hopefully will develop more rapidly in the future. Information on targeting of proteins for degradation via the ubiquitin (Ub) degradation pathway is developing rapidly. Future research must determine how much unity exists across the different eukaryotic systems. At present, it has important implications for protein turnover in plants, since apparently Ub is involved in the degradation of phytochrome. Little information has been developed regarding what triggers increased proteolysis with the onset of senescence, although it appears to involve protein synthesis. Thus far, the evidence indicates that the complement of proteases prior to senescence is sufficient to carry out the observed protein degradation. This field of study has great practical implications, e.g. maintaining photosynthesis during seed‐fill in order to obtain greater crop yields. The current use of ‘stay green’ variants in the populations of several crop plants to produce increased yields shows the potential for future development. The near future should see exciting discoveries in these areas of research that will have far reaching effects on the construction of transgenic plants for future research accomplishments and agricultural use.

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Differential Changes in the Amount of Protein Complexes in the Chloroplast Membrane during Senescence of Oat and Bean Leaves

Cited by 54 publications

References 12 publications

Active Translation of the D-1 Protein of Photosystem II in Senescing Leaves

Active Translation of the D-1 Protein of Photosystem II in Senescing Leaves

Chlorophyll: a symptom and a regulator of plastid development

Proteolytic activity during senescence of plants

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