Roles and Cellular Localization of GBP2 and NAB2 During the Blood Stage of Malaria Parasites

The quality control and export of mRNA by RNA-binding proteins are necessary for the survival of malaria parasites, which have complex life cycles. Nuclear poly(A) binding protein 2 (NAB2), THO complex subunit 4 (THO4), nucleolar protein 3 (NPL3), G-strand binding protein 2 (GBP2) and serine/arginine-rich splicing factor 1 (SR1) are involved in nuclear mRNA export in malaria parasites. However, their roles in asexual and sexual development, and in cellular localization, are not fully understood. In this study using the rodent malaria parasite, Plasmodium berghei, we found that NAB2 and SR1, but not THO4, NPL3 or GBP2, played essential roles in the asexual development of malaria parasites. By contrast, GBP2 but not NPL3 was involved in male and female gametocyte production. THO4 was involved in female gametocyte production, but had a lower impact than GBP2. In this study, we focused on GBP2 and NAB2, which play important roles in the sexual and asexual development of malaria parasites, respectively, and examined their cellular localization. GBP2 localized to both the nucleus and cytoplasm of malaria parasites. Using immunoprecipitation coupled to mass spectrometry (IP-MS), GBP2 interacted with the proteins ALBA4, DOZI, and CITH, which play roles in translational repression. IP-MS also revealed that phosphorylated adapter RNA export protein (PHAX) domain-containing protein, an adaptor protein for exportin-1, also interacted with GBP2, implying that mRNA export occurs via the PHAX domain-containing protein pathway in malaria parasites. Live-cell fluorescence imaging revealed that NAB2 localized at the nuclear periphery. Moreover, IP-MS indicated that NAB2 interacted with transportin. RNA immunoprecipitation coupled to RNA sequencing revealed that NAB2 bound directly to 143 mRNAs, including those encoding 40S and 60S ribosomal proteins. Our findings imply that malaria parasites use an evolutionarily ancient mechanism conserved throughout eukaryotic evolution.

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Mex67p of Schizosaccharomyces pombeInteracts with Rae1p in Mediating mRNA Export

Molecular and Cellular Biology ◽

10.1128/mcb.20.23.8767-8782.2000 ◽

2000 ◽

Vol 20 (23) ◽

pp. 8767-8782 ◽

Cited By ~ 52

Author(s):

Jin Ho Yoon ◽

Dona C. Love ◽

Anjan Guhathakurta ◽

John A. Hanover ◽

Ravi Dhar

Keyword(s):

Nuclear Export ◽

Rna Binding ◽

Fluorescent Protein ◽

Synthetic Lethality ◽

Sequence Similarity ◽

Mrna Export ◽

Nuclear Periphery ◽

Nuclear Pore ◽

Multicopy Suppressor ◽

Accessory Factor

ABSTRACT We identified the Schizosaccharomyces pombe mex67 gene (spmex67) as a multicopy suppressor of rae1-167 nup184-1 synthetic lethality and the rae1-167 tsmutation. spMex67p, a 596-amino-acid-long protein, has considerable sequence similarity to the Saccharomyces cerevisiae Mex67p (scMex67p) and human Tap. In contrast toscMEX67, spmex67 is essential for neither growth nor nuclear export of mRNA. However, an spmex67 null mutation (Δmex67) is synthetically lethal with therae1-167 mutation and accumulates poly(A)+ RNA in the nucleus. We identified a central region (149 to 505 amino acids) within spMex67p that associates with a complex containing Rae1p that complements growth and mRNA export defects of therae1-167 Δmex67 synthetic lethality. This region is devoid of RNA-binding, N-terminal nuclear localization, and the C-terminal nuclear pore complex-targeting regions. The (149–505)-green fluorescent protein (GFP) fusion is found diffused throughout the cell. Overexpression of spMex67p inhibits growth and mRNA export and results in the redistribution of the diffused localization of the (149–505)-GFP fusion to the nucleus and the nuclear periphery. These results suggest that spMex67p competes for essential mRNA export factor(s). Finally, we propose that the 149–505 region of spMex67p could act as an accessory factor in Rae1p-dependent transport and that spMex67p participates at various common steps with Rae1p export complexes in promoting the export of mRNA.

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Polypyrimidine-tract-binding protein: a multifunctional RNA-binding protein

Biochemical Society Transactions ◽

10.1042/bst0360641 ◽

2008 ◽

Vol 36 (4) ◽

pp. 641-647 ◽

Cited By ~ 191

Author(s):

Kirsty Sawicka ◽

Martin Bushell ◽

Keith A. Spriggs ◽

Anne E. Willis

Keyword(s):

Translation Initiation ◽

Cellular Localization ◽

Rna Binding ◽

Binding Protein ◽

Control Cell ◽

Rna Binding Protein ◽

Alternative Form ◽

Polypyrimidine Tract ◽

Polypyrimidine Tract Binding ◽

Polypyrimidine Tract Binding Protein

PTB (polypyrimidine-tract-binding protein) is a ubiquitous RNA-binding protein. It was originally identified as a protein with a role in splicing but it is now known to function in a large number of diverse cellular processes including polyadenylation, mRNA stability and translation initiation. Specificity of PTB function is achieved by a combination of changes in the cellular localization of this protein (its ability to shuttle from the nucleus to the cytoplasm is tightly controlled) and its interaction with additional proteins. These differences in location and trans-acting factor requirements account for the fact that PTB acts both as a suppressor of splicing and an activator of translation. In the latter case, the role of PTB in translation has been studied extensively and it appears that this protein is required for an alternative form of translation initiation that is mediated by a large RNA structural element termed an IRES (internal ribosome entry site) that allows the synthesis of picornaviral proteins and cellular proteins that function to control cell growth and cell death. In the present review, we discuss how PTB regulates these disparate processes.

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Multiple Mechanisms Inactivate the LIN-41 RNA-Binding Protein to Ensure A Robust Oocyte-to-Embryo Transition in Caenorhabditis elegans

10.1101/378398 ◽

2018 ◽

Author(s):

Caroline A. Spike ◽

Gabriela Huelgas-Morales ◽

Tatsuya Tsukamoto ◽

David Greenstein

Keyword(s):

Caenorhabditis Elegans ◽

Rna Binding ◽

Binding Protein ◽

Rna Binding Protein ◽

Adaptor Protein ◽

Protein Translation ◽

Translational Repression ◽

Meiotic Maturation ◽

Oocyte Growth ◽

Translational Repressor

ABSTRACTIn the nematode Caenorhabditis elegans, the conserved LIN-41 RNA-binding protein is a translational repressor that coordinately controls oocyte growth and meiotic maturation. LIN-41 exerts these effects, at least in part, by preventing the premature activation of the cyclin-dependent kinase CDK-1. Here we investigate the mechanism by which LIN-41 is rapidly eliminated upon the onset of meiotic maturation. Elimination of LIN-41 requires the activities of CDK-1 and multiple SCF-type ubiquitin ligase subunits, including the conserved substrate adaptor protein SEL-10/Fbw7/Cdc4, suggesting that LIN-41 is a target of ubiquitin-mediated protein degradation. Within the LIN-41 protein, two non-overlapping regions, Deg-A and Deg-B, are individually necessary for LIN-41 degradation; both contain several potential phosphodegron sequences, and at least one of these sites is required for LIN-41 degradation. Finally, Deg-A and Deg-B are sufficient, in combination, to mediate SEL-10-dependent degradation when transplanted into a different oocyte protein. Although LIN-41 is a potent inhibitor of protein translation and M-phase entry, the failure to eliminate LIN-41 from early embryos does not result in the continued translational repression of LIN-41 oocyte mRNA targets. Based on these observations, we propose a molecular model for the elimination of LIN-41 by SCFSEL-10 and suggest that LIN-41 is inactivated before it is degraded. Furthermore, we provide evidence that another RNA-binding protein, the GLD-1 tumor suppressor, is regulated similarly. Redundant mechanisms to extinguish translational repression by RNA-binding proteins may both control and provide robustness to irreversible developmental transitions, including meiotic maturation and the oocyte-to-embryo transition.

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The RNA-binding protein DRBD18 regulates processing and export of the mRNA encoding Trypanosoma brucei RNA-binding protein 10

10.1101/2021.09.13.460056 ◽

2021 ◽

Author(s):

Tania Bishola Tshitenge ◽

Bin Liu ◽

Christine Clayton

Keyword(s):

Trypanosoma Brucei ◽

Rna Binding ◽

Gene Expression Regulation ◽

Binding Protein ◽

Mrna Export ◽

Rna Binding Protein ◽

Tsetse Flies ◽

Nuclear Pore ◽

Regulatory Sequences ◽

Mrna Isoforms

The parasite Trypanosoma brucei grows as bloodstream forms in mammalian hosts, and as procyclic forms in tsetse flies. Trypanosome protein coding genes are arranged in polycistronic transcription units, so gene expression regulation depends heavily on post-transcriptional mechanisms. The essential RNA-binding protein RBP10 is expressed only in mammalian-infective forms, where it targets procyclic-specific mRNAs for destruction. We show that developmental regulation of RBP10 expression is mediated by the exceptionally long 7.3 Kb 3'-UTR of its mRNA. Different regulatory sequences that can independently enhance mRNA stability and translation in bloodstream forms, or destabilize and repress translation in procyclic forms, are scattered throughout the 3'-UTR. The RNA-binding protein DRBD18 is implicated in the export of a subset of mRNAs from the nucleus in procyclic forms. We confirmed that in bloodstream forms, DRBD18 copurifies the outer ring of the nuclear pore, mRNA export proteins and exon junction complex proteins. Loss of DRBD18 in bloodstream forms caused accumulation of several shortened RBP10 mRNA isoforms, with loss of longer species, but RNAi targeting the essential export factor MEX67 did not cause such changes, demonstrating specificity. Long RBP10 mRNAs accumulated in the nucleus, while shorter ones reached the cytoplasm. We suggest that DRBD18 binds to processing signals in the RBP10 3'-UTR, simultaneously preventing their use and recruiting mRNA export factors. DRBD18 depletion caused truncation of the 3'-UTRs of more than 100 other mRNAs, suggesting that it has an important role in regulating use of alternative processing sites.

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TAP/NXF1, the primary mRNA export receptor, specifically interacts with a neuronal RNA-binding protein HuD

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2004.06.140 ◽

2004 ◽

Vol 321 (2) ◽

pp. 291-297 ◽

Cited By ~ 19

Author(s):

Kuniaki Saito ◽

Toshinobu Fujiwara ◽

Jun Katahira ◽

Kunio Inoue ◽

Hiroshi Sakamoto

Keyword(s):

Rna Binding ◽

Binding Protein ◽

Mrna Export ◽

Rna Binding Protein

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The RNA-binding protein LUC7L2 mediates MITA/STING intron retention to negatively regulate innate antiviral response

Cell Discovery ◽

10.1038/s41421-021-00277-y ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Chen Li ◽

Lu Feng ◽

Wei-Wei Luo ◽

Cao-Qi Lei ◽

Mi Li ◽

...

Keyword(s):

Immune Response ◽

Innate Immune Response ◽

Rna Binding ◽

Binding Protein ◽

Rna Binding Protein ◽

Adaptor Protein ◽

Antiviral Response ◽

Innate Immune ◽

Innate Antiviral Response ◽

Hsv 1

AbstractMITA (also known as STING) is an ER-located adaptor protein, which mediates DNA-triggered innate immune response and is critically involved in autoimmune diseases and tumorigenesis. MITA is regulated by post-translational modifications, but how post-transcriptional mechanisms are involved in the regulation of MITA is still largely unknown. Here, we identified the RNA-binding protein LUC7L2 as a negative regulator of DNA virus-triggered innate immune response. LUC7L2-deficient mice exhibited resistance to lethal herpes simplex virus 1 (HSV-1) infection and reduced HSV-1 loads in the brain. Mechanistically, LUC7L2 directly bound to intron 3 of MITA precursor messenger RNA, inhibited its splicing and promoted its nonsense-mediated decay, leading to its downregulation at protein level. LUC7L2-deficient cells had markedly increased MITA level, leading to heightened innate antiviral response. Finally, LUC7L2 was induced following HSV-1 infection. Our findings reveal a feedback negative post-transcriptional regulatory mechanism for regulation of MITA-mediated innate immune response to viral and aberrant cellular DNA.

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PfAlbas constitute a new eukaryotic DNA/RNA-binding protein family in malaria parasites

Nucleic Acids Research ◽

10.1093/nar/gkr1215 ◽

2011 ◽

Vol 40 (7) ◽

pp. 3066-3077 ◽

Cited By ~ 51

Author(s):

Arnaud Chêne ◽

Shruthi S. Vembar ◽

Loïc Rivière ◽

José Juan Lopez-Rubio ◽

Aurelie Claes ◽

...

Keyword(s):

Rna Binding ◽

Binding Protein ◽

Rna Binding Protein ◽

Protein Family ◽

Malaria Parasites ◽

Eukaryotic Dna

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The RNA binding protein FMR1 controls selective exosomal miRNA cargo loading during inflammation

The Journal of Cell Biology ◽

10.1083/jcb.201912074 ◽

2020 ◽

Vol 219 (10) ◽

Cited By ~ 4

Author(s):

Ann L. Wozniak ◽

Abby Adams ◽

Kayla E. King ◽

Winston Dunn ◽

Lane K. Christenson ◽

...

Keyword(s):

Rna Binding ◽

Inflammatory Responses ◽

Binding Protein ◽

Rna Binding Protein ◽

Adaptor Protein ◽

Inflammasome Activation ◽

Sequence Motif ◽

Cell Periphery ◽

Transport Pathway ◽

Exosomal Mirna

Cells respond to inflammatory disease states by releasing exosomes containing highly specific protein and RNA cargos, but how inflammation alters cargo specificity and secretion of exosomes is unknown. We show that increases in exosome secretion induced by either viral infection or LPS/ATP exposure result from inflammasome activation and subsequent caspase-1–dependent cleavage of the trafficking adaptor protein RILP. This cleaved form of RILP promotes the movement of multivesicular bodies toward the cell periphery and induces selective exosomal miRNA cargo loading. We have identified a common short sequence motif present in miRNAs that are selectively loaded into exosomes after RILP cleavage. This motif binds the RNA binding protein FMR1 and directs miRNA loading into exosomes via interaction with components of the ESCRT (endosomal sorting complex required for transport) pathway. These results indicate that inflammasome-mediated RILP cleavage, and sequence-specific interactions between miRNAs and FMR1, play a significant role in exosome cargo loading and enhanced secretion during cellular inflammatory responses.

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