Transient interaction of cpSRP54 with elongating nascent chains of the chloroplast‐encoded D1 protein; ‘cpSRP54 caught in the act’

Nilsson, Robert; Wijk, Klaas J. van

doi:10.1016/s0014-5793(02)03016-8

Cited by 64 publications

(49 citation statements)

References 29 publications

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“…A transient binding between cpSRP54 and the nascent protein attached to the ribosome has been demonstrated during the early phase of elongation with the binding affinity decreasing as elongation proceeds [163]. The interaction of cpSRP54 with cpFtsY stimulates GTP hydrolysis and the nascent chain is passed on to the Alb3/Sec translocon [162].…”

Section: The Sec Machinery In Chloroplast Thylakoids (Cpsec)mentioning

confidence: 99%

Protein import machineries in endosymbiotic organelles

Balsera

Soll

Bölter

2009

Cell. Mol. Life Sci.

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Abstract. Chloroplast and mitochondria, the two organelles with an accepted endosymbiotic origin, have developed multiple translocation pathways to ensure the subcellular allocation of proteins synthesized by cytosolic ribosomes, and to guarantee their assembly into functional complexes in coordination also with organellar-encoded subunits. The evolution of different protein import machineries was thus essential for the development of these two organelles within cells. A general overview of the translocation machineries in chloroplast and mitochondrial membranes involved in targeting and import of nuclearencoded proteins, with special focus on plant cells where the two organelles coexist, is expounded.Keywords. Protein translocation, mitochondria, chloroplasts, thylakoids, dual-targeting, endosymbiotic organelles. Endosymbiosis and the plant cellIt is widely accepted that mitochondria, found in eukaryotic cells, and plastids, just in plant cells, are organelles of endosymbiotic origin [1]. Two independent endosymbiotic events gave rise to the evolution of these organelles in a plant cell. First, mitochondria evolved from a single endosymbiotic event between a host cell and an aerobic a-proteobacterium. As a consequence, a diversity of heterotrophic eukaryotic lineages emerged [2]. Later, plastids were incorporated from a free-living photosynthetic prokaryote, an ancestor of contemporary cyanobacteria, which was engulfed by a heterotrophic eukaryotic host that already contained mitochondria. The primary endosymbiotic event in plastid evolution gave rise to glaucophyta, rhodophyta and viridiplantae lineages [3]. Subsequent endosymbiotic events in plastid evolution have occurred [4]. With time, the majority of the genetic information from the endosymbionts was lost or transferred to the nucleus of the host cell, though some amount of information is still retained by the organelles, thus functioning as a semiautonomous system [5]. Because of the gene relocation in the host cell, several mechanisms were developed to re-target and efficiently transport the proteins acting in the organelles but now expressed in the host cytosol. Some of these machineries were adapted from bacteria; others show

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Section: The Sec Machinery In Chloroplast Thylakoids (Cpsec)mentioning

confidence: 99%

Protein import machineries in endosymbiotic organelles

Balsera

Soll

Bölter

2009

Cell. Mol. Life Sci.

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“…In vascular plants, two different cpSRP-dependent pathways have been identified, one post-translational for proteins imported into the chloroplast, and the other co-translational for plastid-encoded proteins (Groves et al 2001;Rosenblad and Samuelsson 2004). In fact, a transient interaction between cpSRP54 and elongating D1 protein was observed using an in vitro chloroplast translation system (Nilsson and van Wijk 2002). Additionally, the finding of RNAbinding proteins (RBPs) in membranous fractions led to a hypothesis in which these proteins may localize different mRNAs to be translated in specific chloroplast membranes.…”

Section: Localization Of Translationmentioning

confidence: 99%

Chloroplast translation regulation

et al. 2007

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Chloroplast gene expression is primarily controlled during the translation of plastid mRNAs. Translation is regulated in response to a variety of biotic and abiotic factors, and requires a coordinate expression with the nuclear genome. The translational apparatus of chloroplasts is related to that of bacteria, but has adopted novel mechanisms in order to execute the specific roles that this organelle performs within a eukaryotic cell. Accordingly, plastid ribosomes contain a number of chloroplast-unique proteins and domains that may function in translational regulation. Chloroplast translation regulation involves cis-acting RNA elements (located in the mRNA 5' UTR) as well as a set of corresponding trans-acting protein factors. While regulation of chloroplast translation is primarily controlled at the initiation steps through these RNA-protein interactions, elongation steps are also targets for modulating chloroplast gene expression. Translation of chloroplast mRNAs is regulated in response to light, and the molecular mechanisms underlying this response involve changes in the redox state of key elements related to the photosynthetic electron chain, fluctuations of the ADP/ATP ratio and the generation of a proton gradient. Photosynthetic complexes also experience assembly-related autoinhibition of translation to coordinate the expression of different subunits of the same complex. Finally, the localization of all these molecular events among the different chloroplast subcompartments appear to be a crucial component of the regulatory mechanisms of chloroplast gene expression.

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“…During the evolution of higher plant chloroplasts from a cyanobacterial endosymbiont, the SRP54 component was retained (chloroplast (cp) SRP54), whereas the SRP RNA was lost. One pool of cpSRP54 cofractionates with plastid ribosomes (3) and can be cross-linked to the nascent chains of the photosystem II reaction center protein D1 (4,5). This finding implies that it is involved in the cotranslational transport of at least some plastid-encoded proteins and functions in the absence of an SRP RNA component.…”

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confidence: 99%

Chloroplast SRP54 Was Recruited for Posttranslational Protein Transport via Complex Formation with Chloroplast SRP43 during Land Plant Evolution

Dünschede

Träger

Schröder

et al. 2015

Journal of Biological Chemistry

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Background: In chloroplasts of higher plants, a heterodimeric cpSRP43⅐cpSRP54 complex targets LHC proteins to the thylakoid membrane. Results: In green algae, cpSRP43 alone forms a targeting complex with LHC proteins. Conclusion: The coevolution of LHC proteins and cpSRP43 occurred independently of complex formation with cpSRP54. Significance: The results provide new insights into the evolution of cpSRP-dependent protein transport.

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Transient interaction of cpSRP54 with elongating nascent chains of the chloroplast‐encoded D1 protein; ‘cpSRP54 caught in the act’

Cited by 64 publications

References 29 publications

Protein import machineries in endosymbiotic organelles

Protein import machineries in endosymbiotic organelles

Chloroplast translation regulation

Chloroplast SRP54 Was Recruited for Posttranslational Protein Transport via Complex Formation with Chloroplast SRP43 during Land Plant Evolution

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