The presequence of the precursor to the nucleus-encoded 30 kDa protein of photosystem II in Euglena gracilis Z includes two hydrophobic domains

Shigemori, Yasushi; Inagaki, Jiro; Mori, Hitoshi; Nishimura, Mikio; Takahashi, Sumio; Yamamoto, Yasusi

doi:10.1007/bf00040587

Cited by 15 publications

(9 citation statements)

References 29 publications

(28 reference statements)

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“…We independently sequenced and determined a complete cDNA for the preOEC30. The previously published preOEC30 lacks 46 amino acids from the N-terminus corresponding to the N-terminal signal peptide domain (19). We compared the presequences of Euglena preOEC30 and the preOEC33s from higher plants (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Protein Translocation within Chloroplast Is Similar in Euglena and Higher Plants

Inagaki

Fujita

Hase

et al. 2000

Biochemical and Biophysical Research Communications

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Section: Resultsmentioning

confidence: 99%

“…We performed heterologous import experiments using isolated chloroplasts from spinach and previously obtained Euglena truncated preOEC30 (Euglena T-preOEC30), which lacks N-terminal signal peptide domain (19). We demonstrated that the Euglena T-preOEC30 having the stroma targeting domain and thylakoid transfer domain can be imported into spinach chloroplasts.…”

mentioning

confidence: 96%

Protein Translocation within Chloroplast Is Similar in Euglena and Higher Plants

Inagaki

Fujita

Hase

et al. 2000

Biochemical and Biophysical Research Communications

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“…In both cases, plastid proteins are targeted through the endomembrane system (49,53,67,70,71). From studies of several complete, publicly available Euglena gracilis plastid protein sequences (13,25,27,28,38,44,52,56,61,64,66,73), it was predicted that the plastid proteins have an N-terminal signal sequence, an inference that was confirmed by both in vitro (38) and in vivo (70,71) experimental approaches. Following the signal sequence is the predicted transit peptide, which is sufficient for translocation across plant chloroplast membranes (29), and a hydrophobic region that acts as a "stoptransfer" sequence to prevent complete transport into the ER, such that the mature protein remains in the cytoplasm (69).…”

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confidence: 97%

Analysis of Euglena gracilis Plastid-Targeted Proteins Reveals Different Classes of Transit Sequences

2006

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The plastid of Euglena gracilis was acquired secondarily through an endosymbiotic event with a eukaryotic green alga, and as a result, it is surrounded by a third membrane. This membrane complexity raises the question of how the plastid proteins are targeted to and imported into the organelle. To further explore plastid protein targeting in Euglena, we screened a total of 9,461 expressed sequence tag (EST) clusters (derived from 19,013 individual ESTs) for full-length proteins that are plastid localized to characterize their targeting sequences and to infer potential modes of translocation. Of the 117 proteins identified as being potentially plastid localized whose N-terminal targeting sequences could be inferred, 83 were unique and could be classified into two major groups. Class I proteins have tripartite targeting sequences, comprising (in order) an N-terminal signal sequence, a plastid transit peptide domain, and a predicted stop-transfer sequence. Within this class of proteins are the lumen-targeted proteins (class IB), which have an additional hydrophobic domain similar to a signal sequence and required for further targeting across the thylakoid membrane. Class II proteins lack the putative stop-transfer sequence and possess only a signal sequence at the N terminus, followed by what, in amino acid composition, resembles a plastid transit peptide. Unexpectedly, a few unrelated plastid-targeted proteins exhibit highly similar transit sequences, implying either a recent swapping of these domains or a conserved function. This work represents the most comprehensive description to date of transit peptides in Euglena and hints at the complex routes of plastid targeting that must exist in this organism.A fundamental problem in cell biology is the precise and efficient targeting of proteins synthesized by cytoplasmic ribosomes to their appropriate intracellular locations. Proteins destined for the endomembrane system, mitochondria, or the chloroplast usually have specific N-terminal targeting domains that are required for proper subcellular localization. These leader sequences are often removed by specific proteases at the protein's destination prior to it assuming its active conformation. For chloroplast-targeted proteins in plants and algae, an N-terminal transit peptide (TP) is both necessary and sufficient for correct plastid targeting (11). Transit peptides are not conserved in sequence but exhibit characteristic biochemical properties, such as an elevated content of the hydroxylated amino acids serine and threonine as well as a deficiency of acidic (aspartate and glutamate) amino acids (76). Within a typical chloroplast, there are six distinct locations to which the constituent proteins must be sorted, and some proteins have to cross up to three membranes (33). This complexity requires additional targeting information within the transit peptide, such as the signal sequence-like domain found in proteins targeted to the thylakoid membrane, or information contained within the mature portion of the protein itself...

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“…The class I presequences were previously identified in a number of Euglena chloroplast protein precursors including but not limited to polyprotein precursors (Chan et al 1990;Henze et al 1995;Houlne and Schantz 1987;Kishore et al 1993;Lin et al 1994;Plaumann et al 1997;Santillan Torres et al 2003;Sharif et al 1989;Shigemori et al 1994;Vacula et al 1999). The class I presequence has an N-terminal presequence composed of a predicted signal peptide, for targeting to the ER ( Fig.…”

Section: The Euglena Plastid Targeting Presequence Structure; Two-clamentioning

confidence: 94%

“…Early sequencing efforts of Euglena genes encoding a number of plastid-targeted proteins identified a large bipartite presequence composed of an N-terminal domain having characteristics of a signal peptide that mediates co-translational import into the ER and a second domain having features resembling a transit peptide that mediates import into chloroplasts (Chan et al 1990;Henze et al 1995;Houlne and Schantz 1987;Kishore et al 1993;Lin et al 1994;Plaumann et al 1997;Santillan Torres et al 2003;Sharif et al 1989;Shigemori et al 1994;Vacula et al 1999). Considering the evidence, the absence of ribosomes on the outer plastid envelope membrane, the immunogold localization of LHCPII to the Golgi apparatus and the presence of a N-terminal presequence signal peptide provided compelling evidence for co-translational transport of chloroplast protein precursors into the ER, vesicular transport from the ER to the Golgi apparatus and then from the Golgi apparatus to the chloroplast for subsequent translocation through the plastid envelope into the plastid.…”

Section: Introductionmentioning

confidence: 98%

Protein Targeting to the Plastid of Euglena

Durnford

Schwartzbach

2017

Advances in Experimental Medicine and Biology

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The lateral transfer of photosynthesis between kingdoms through endosymbiosis is among the most spectacular examples of evolutionary innovation. Euglena, which acquired a chloroplast indirectly through an endosymbiosis with a green alga, represents such an example. As with other endosymbiont-derived plastids from eukaryotes, there are additional membranes that surround the organelle, of which Euglena has three. Thus, photosynthetic genes that were transferred from the endosymbiont to the host nucleus and whose proteins are required in the new plastid, are now faced with targeting and plastid import challenges. Early immunoelectron microscopy data suggested that the light-harvesting complexes, photosynthetic proteins in the thylakoid membrane, are post-translationally targeted to the plastid via the Golgi apparatus, an unexpected discovery at the time. Proteins targeted to the Euglena plastid have complex, bipartite presequences that direct them into the endomembrane system, through the Golgi apparatus and ultimately on to the plastid, presumably via transport vesicles. From transcriptome sequencing, dozens of plastid-targeted proteins were identified, leading to the identification of two different presequence structures. Both have an amino terminal signal peptide followed by a transit peptide for plastid import, but only one of the two classes of presequences has a third domain-the stop transfer sequence. This discovery implied two different transport mechanisms; one where the protein was fully inserted into the lumen of the ER and another where the protein remains attached to, but effectively outside, the endomembrane system. In this review, we will discuss the biochemical and bioinformatic evidence for plastid targeting, discuss the evolution of the targeting system, and ultimately provide a working model for the targeting and import of proteins into the plastid of Euglena.

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The presequence of the precursor to the nucleus-encoded 30 kDa protein of photosystem II in Euglena gracilis Z includes two hydrophobic domains

Cited by 15 publications

References 29 publications

Protein Translocation within Chloroplast Is Similar in Euglena and Higher Plants

Protein Translocation within Chloroplast Is Similar in Euglena and Higher Plants

Analysis of Euglena gracilis Plastid-Targeted Proteins Reveals Different Classes of Transit Sequences

Protein Targeting to the Plastid of Euglena

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