Excitation Energy Transfer: Functional and Dynamic Aspects of Lhc (cab) Proteins

Melis, Anastasios

doi:10.1007/0-306-48127-8_29

Cited by 30 publications

(33 citation statements)

References 123 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In spite of the substantial number of physiological and biochemical studies on this phenomenon (reviewed in [4,5,9]), genes and mechanism for the regulation of the Chl antenna size of photosynthesis have not been fully elucidated. Earlier DNA insertional mutagenesis work from this laboratory identified the novel TLA1 gene (GenBank accession no.…”

Section: Discussionmentioning

confidence: 99%

Modulation of the light-harvesting chlorophyll antenna size in Chlamydomonas reinhardtii by TLA1 gene over-expression and RNA interference

Mitra

Kirst

Dewez

et al. 2012

Phil. Trans. R. Soc. B

Self Cite

View full text Add to dashboard Cite

Truncated light-harvesting antenna 1 (TLA1) is a nuclear gene proposed to regulate the chlorophyll (Chl) antenna size in Chlamydomonas reinhardtii. The Chl antenna size of the photosystems and the chloroplast ultrastructure were manipulated upon TLA1 gene over-expression and RNAi downregulation. The TLA1 over-expressing lines possessed a larger chlorophyll antenna size for both photosystems and contained greater levels of Chl b per cell relative to the wild type. Conversely, TLA1 RNAi transformants had a smaller Chl antenna size for both photosystems and lower levels of Chl b per cell. Western blot analyses of the TLA1 over-expressing and RNAi transformants showed that modulation of TLA1 gene expression was paralleled by modulation in the expression of light-harvesting protein, reaction centre D1 and D2, and VIPP1 genes. Transmission electron microscopy showed that modulation of TLA1 gene expression impacts the organization of thylakoid membranes in the chloroplast. Over-expressing lines showed well-defined grana, whereas RNAi transformants possessed loosely held together and more stroma-exposed thylakoids. Cell fractionation suggested localization of the TLA1 protein in the inner chloroplast envelope and potentially in association with nascent thylakoid membranes, indicating a role in Chl antenna assembly and thylakoid membrane biogenesis. The results provide a mechanistic understanding of the Chl antenna size regulation by the TLA1 gene.

show abstract

Section: Discussionmentioning

confidence: 99%

Modulation of the light-harvesting chlorophyll antenna size in Chlamydomonas reinhardtii by TLA1 gene over-expression and RNA interference

Mitra

Kirst

Dewez

et al. 2012

Phil. Trans. R. Soc. B

Self Cite

View full text Add to dashboard Cite

show abstract

“…The overall changes of the PSII antenna in response to variations in the light environment for different plant species have been thoroughly described (Osmond, 1994;Melis, 1996). Despite the wealth of physiological information, the underlying molecular mechanisms for the differences in antenna composition and the dynamic acclimations are still not understood.…”

Section: Discussionmentioning

confidence: 99%

“…Despite the wealth of physiological information, the underlying molecular mechanisms for the differences in antenna composition and the dynamic acclimations are still not understood. The expression of the nuclear cab genes encoding LHCII is light regulated at both the transcriptional and translational levels (Green and Salter, 1996), and the hierarchy of Cab protein assembly during biogenesis has been characterized (Melis, 1996). Aside from the recently discovered proteolytic process (Lindahl et al, 1995;Lindahl, 1997), the process of reduction of the LHCII antenna during acclimation to elevated light intensities is basically unknown.…”

Section: Discussionmentioning

confidence: 99%

“…It is not only a key component for light harvesting, but is also essential for regulation and distribution of excitation energy within the photosynthetic apparatus and responds to both short-and long-term fluctuations in light intensity and quality (Anderson and Andersson, 1988;Melis, 1991Melis, , 1996. This acclimation of the light-harvesting apparatus is generally thought to optimize photosynthetic efficiency and minimize light stress and photoinhibition to PSII (Andersson and Barber, 1996;Melis, 1996;Park et al, 1997).The identified proteolytic activity was associated with degradation of the so-called "outer" or "peripheral" pool of LHCII enriched in the rapidly phosphorylated 25-kD subunit (Larsson et al, 1987a(Larsson et al, , 1987b Anderson and Andersson, 1988) …”

mentioning

confidence: 99%

See 1 more Smart Citation

Induction of Acclimative Proteolysis of the Light-Harvesting Chlorophyll a/b Protein of Photosystem II in Response to Elevated Light Intensities

et al. 1998

View full text Add to dashboard Cite

Most plants have the ability to respond to fluctuations in light to minimize damage to the photosynthetic apparatus. A proteolytic activity has been discovered that is involved in the degradation of the major light-harvesting chlorophyll a/b-binding protein of photosystem II (LHCII) when the antenna size of photosystem II is reduced upon acclimation of plants from low to high light intensities. This ATP-dependent proteolytic activity is of the serine or cysteine type and is associated with the outer membrane surface of the stroma-exposed thylakoid regions. The identity of the protease is not known, but it does not correspond to the recently identified chloroplast ATP-dependent proteases Clp and FtsH, which are homologs to bacterial enzymes. The acclimative response shows a delay of 2 d after transfer of the leaves to high light. This lag period was shown to be attributed to expression or activation of the responsible protease. Furthermore, the LHCII degradation was found to be regulated at the substrate level. The degradation process involves lateral migration of LHCII from the appressed to the nonappressed thylakoid regions, which is the location for the responsible protease. Phosphorylated LHCII was found to be a poor substrate for degradation in comparison with the unphosphorylated form of the protein. The relationship between LHCII degradation and other regulatory proteolytic processes in the thylakoid membrane, such as D1-protein degradation, is discussed.The main focus of photosynthesis research has been the functional and structural aspects behind the energytransducing process. The progress has been significant, and the photosynthetic protein complexes can now be described at a very refined molecular level (Barber and Andersson, 1994). Conversely, relatively little is known about the acclimating, regulatory, and protective processes that maintain high photosynthetic efficiency during everfluctuating and even stressful environmental conditions.The identification of such auxiliary processes associated with thylakoid membranes and the characterization of the enzymes involved are therefore central tasks of current photosynthesis research. Examples of auxiliary enzymes or components are kinases and phosphatases responsible for reversible protein phosphorylation (Gal et al., 1997), desaturases controlling the lipid composition and dynamics of thylakoid membranes (Wada et al., 1990), stress-induced proteins such as the ELIPs (Adamska, 1997), and several enzymatic activities involved in various forms of regulatory proteolysis Andersson and Aro, 1997). In the latter case, D1-protein turnover during repair of damage caused by photoinhibition is the most illustrative example (Prasil et al., 1992; Andersson and Aro, 1997). The knowledge of chloroplast proteases involved in regulatory proteolysis is still very limited. The presence of homologs to bacterial proteases in chloroplasts, such as the Clp and FtsH proteins, has provided new insights and possibilities (Gray et al., 1990;Moore and Keegstra, 1993; Lindahl et...

show abstract

“…2 and its inset were simulated with the set of rate constants determined for these processes by Roelofs et al (1992) and this set will be used, except of some simulated FLRs in Fig. 3 (see below), in all following simulations because these values were determined from fluorescence measurements and with plant material with 250 chlorophylls per P680 that is the typical number of all the pigments in complete PSII (see Melis, 1996 for review). However, to see the effect of values of these rate constants, the FLRs were also simulated for the sets of rate constants first determined by Schatz et al (1988) and Leibl et al (1989), and among others, recently reported by Gibasiewicz et al (2001) Table 2 and the results of the simulations are shown in Fig.…”

Section: Role Of Processes That Are Fast Enough To Compete With Fluormentioning

confidence: 99%

Chlorophyll a Fluorescence Rise Induced by High Light Illumination of Dark-adapted Plant Tissue Studied by Means of a Model of Photosystem II and Considering Photosystem II Heterogeneity

Lazár

2003

Journal of Theoretical Biology

154

113

View full text Add to dashboard Cite

Excitation Energy Transfer: Functional and Dynamic Aspects of Lhc (cab) Proteins

Cited by 30 publications

References 123 publications

Modulation of the light-harvesting chlorophyll antenna size in Chlamydomonas reinhardtii by TLA1 gene over-expression and RNA interference

Modulation of the light-harvesting chlorophyll antenna size in Chlamydomonas reinhardtii by TLA1 gene over-expression and RNA interference

Induction of Acclimative Proteolysis of the Light-Harvesting Chlorophyll a/b Protein of Photosystem II in Response to Elevated Light Intensities

Chlorophyll a Fluorescence Rise Induced by High Light Illumination of Dark-adapted Plant Tissue Studied by Means of a Model of Photosystem II and Considering Photosystem II Heterogeneity

Contact Info

Product

Resources

About