Subcellular localization of ribosomal P0-like protein MRT4 is determined by its N-terminal domain

Michalec, B.; Krokowski, Dawid; Grela, Przemysław; Wawiórka, Leszek; Sawa-Makarska, Justyna; Grankowski, Nikodem; Tchórzewski, Marek

doi:10.1016/j.biocel.2010.01.011

Cited by 23 publications

(28 citation statements)

References 60 publications

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“…This observation, together with the fact that a Mrt4-P0 chimera protein, containing as N-terminal domain the Mrt4 ORF, is able to partially complement the otherwise lethal absence of P0 29, and that a truncated P0 r-protein lacking its C-terminal domain functionally resembles Mrt4 38, strongly suggest that P0 and Mrt4 compete for the same rRNA site in r-particles, thus, successively occupying this site during LSU maturation 29. A similar scenario has been reported for human Mrt4 and P0 39. In full agreement with this hypothesis, the cryo-electron microscopy (cryo-EM) reconstruction of two distinct yeast pre-60S r-particles, which carry Mrt4 but lack P0, has revealed that indeed in these particles Mrt4 unequivocally localizes to a position equivalent to the one of P0 in the P-stalk of the mature LSU (Figures 1A and 1C) 4041.…”

Section: The Classical View: Paralogues Of Ribosomal Proteinssupporting

confidence: 68%

Placeholder factors in ribosome biogenesis: please, pave my way

Espinar-Marchena¹,

Babiano²,

Cruz³

2017

Microb Cell

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The synthesis of cytoplasmic eukaryotic ribosomes is an extraordinarily energy-demanding cellular activity that occurs progressively from the nucleolus to the cytoplasm. In the nucleolus, precursor rRNAs associate with a myriad of trans-acting factors and some ribosomal proteins to form pre-ribosomal particles. These factors include snoRNPs, nucleases, ATPases, GTPases, RNA helicases, and a vast list of proteins with no predicted enzymatic activity. Their coordinate activity orchestrates in a spatiotemporal manner the modification and processing of precursor rRNAs, the rearrangement reactions required for the formation of productive RNA folding intermediates, the ordered assembly of the ribosomal proteins, and the export of pre-ribosomal particles to the cytoplasm; thus, providing speed, directionality and accuracy to the overall process of formation of translation-competent ribosomes. Here, we review a particular class of trans-acting factors known as "placeholders". Placeholder factors temporarily bind selected ribosomal sites until these have achieved a structural context that is appropriate for exchanging the placeholder with another site-specific binding factor. By this strategy, placeholders sterically prevent premature recruitment of subsequently binding factors, premature formation of structures, avoid possible folding traps, and act as molecular clocks that supervise the correct progression of pre-ribosomal particles into functional ribosomal subunits. We summarize the current understanding of those factors that delay the assembly of distinct ribosomal proteins or subsequently bind key sites in pre-ribosomal particles. We also discuss recurrent examples of RNA-protein and protein-protein mimicry between rRNAs and/or factors, which have clear functional implications for the ribosome biogenesis pathway.

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Section: The Classical View: Paralogues Of Ribosomal Proteinssupporting

confidence: 68%

Placeholder factors in ribosome biogenesis: please, pave my way

Espinar-Marchena¹,

Babiano²,

Cruz³

2017

Microb Cell

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“…Mrt4 is not P0 isoform but rather it is a pre-60S trans-acting factor (Kemmler et al, 2009;Lo et al, 2009;Rodriguez-Mateos et al, 2009). Mrt4 shares sequence similarity to P0 proteins in yeast and humans, and P0 together with P1/P2 and L12 form the ribosomal stalk responsible for translation factordependent GTP hydrolysis (Michalec et al, 2010). Mrt4 binds to pre-60S during its shuttling between the nucleus and the cytoplasm at the same site in the ribosome as P0 but is displaced by P0 in the cytosol on ribosome maturation (Michalec-Wawiorka et al, 2015).…”

Section: Turnover Of Ribosomal Proteinsmentioning

confidence: 99%

Refining the composition of the Arabidopsis thaliana 80S cytosolic ribosome

Duncan

et al. 2019

Preprint

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The cytosolic 80S ribosome is composed of protein and RNA molecules and its function in protein synthesis is modulated through interaction with other cytosolic components. Defining the role of each of the proteins associated with ribosomes in plants is a major challenge which is hampered by difficulties in attribution of different proteins to roles in ribosome biogenesis, the mature cytosolic ribosome (r-proteins) or to the broader translatome associated with functioning ribosomes. Here we refined the core r-protein composition in plants by determining the abundance of proteins in low, partially and highly purified ribosomal samples from Arabidopsis thaliana cell cultures. To characterise this list of proteins further we determined their degradation (KD) and synthesis (KS) rate by progressive labelling with 15 N combined with peptide mass spectrometry analysis. The turnover rates of 55 r-proteins, including 26 r-proteins from the 40S subunit and 29 r-proteins from the 60S subunit could be determined. Overall, ribosome proteins showed very similar KD and KS rates suggesting that half of the ribosome population is replaced every 3-4 days. Three proteins showed significantly shorter half-lives; ribosomal protein P0D (RPP0D) with a half-life of 0.5 days and RACK1b and c with half-lives of 1-1.4 days. The ribosomal RPP0D protein is a homolog of the human Mrt4 protein, a trans-acting factor in the assembly of the pre-60S particle, while RACK1 has known regulatory roles in cell function beyond its role as a 40S subunit. Our experiments also identified 58 proteins that are not from r-protein families but co-purify with ribosomes and co-express with rproteins in Arabidopsis. Of this set, 26 were enriched more than 10-fold during ribosome purification. A number have known roles in translation or ribosome-association while others are newly proposed ribosome-associated factors in plants. This analysis provides a more robust understanding of Arabidopsis ribosome content, shows that most r-proteins turnover in unison in vivo, identifies a novel set of potential plant translatome components, and reveals how protein turnover can identify r-proteins involved in ribosome biogenesis or regulation in plants. Data are available via ProteomeXchange with identifier PXD012839.

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“…25 The early nucleolar GAC is composed of uL11 and uL10-like protein (trans-acting factors called Mrt4), which occupies the uL10 binding site. 26,27 It is postulated that uL11 and Mrt4 are important for proper spatial organization of early GAC and subsequent Yvh1 driven P-stalk loading, which gives rise to mature GAC formation. 28 Correctly assembled GAC becomes a functional checkpoint for verification of 60S translational capacity.…”

Section: Introductionmentioning

confidence: 99%

Functional analysis of the uL11 protein impact on translational machinery

Wawiórka¹,

Molestak²,

Szajwaj³

et al. 2016

Cell Cycle

Self Cite

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The ribosomal GTPase associated center constitutes the ribosomal area, which is the landing platform for translational GTPases and stimulates their hydrolytic activity. The ribosomal stalk represents a landmark structure in this center, and in eukaryotes is composed of uL11, uL10 and P1/P2 proteins. The modus operandi of the uL11 protein has not been exhaustively studied in vivo neither in prokaryotic nor in eukaryotic cells. Using a yeast model, we have brought functional insight into the translational apparatus deprived of uL11, filling the gap between structural and biochemical studies. We show that the uL11 is an important element in various aspects of 'ribosomal life'. uL11 is involved in 'birth' (biogenesis and initiation), by taking part in Tif6 release and contributing to ribosomal subunit-joining at the initiation step of translation. uL11 is particularly engaged in the 'active life' of the ribosome, in elongation, being responsible for the interplay with eEF1A and fidelity of translation and contributing to a lesser extent to eEF2-dependent translocation. Our results define the uL11 protein as a critical GAC element universally involved in trGTPase 'productive state' stabilization, being primarily a part of the ribosomal element allosterically contributing to the fidelity of the decoding event.

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Subcellular localization of ribosomal P0-like protein MRT4 is determined by its N-terminal domain

Cited by 23 publications

References 60 publications

Placeholder factors in ribosome biogenesis: please, pave my way

Placeholder factors in ribosome biogenesis: please, pave my way

Refining the composition of the Arabidopsis thaliana 80S cytosolic ribosome

Functional analysis of the uL11 protein impact on translational machinery

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