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Bai N, Adeshina Y, Bychkov I, Xia Y, Gowthaman R, Miller SA, Gupta AK, Johnson DK, Lan L, Golemis EA, Makhov PB, Xu L, Pillai MM, Boumber Y, Karanicolas J. Rationally designed inhibitors of the Musashi protein-RNA interaction by hotspot mimicry. RESEARCH SQUARE 2023:rs.3.rs-2395172. [PMID: 36711552 PMCID: PMC9882606 DOI: 10.21203/rs.3.rs-2395172/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
RNA-binding proteins (RBPs) are key post-transcriptional regulators of gene expression, and thus underlie many important biological processes. Here, we developed a strategy that entails extracting a "hotspot pharmacophore" from the structure of a protein-RNA complex, to create a template for designing small-molecule inhibitors and for exploring the selectivity of the resulting inhibitors. We demonstrate this approach by designing inhibitors of Musashi proteins MSI1 and MSI2, key regulators of mRNA stability and translation that are upregulated in many cancers. We report this novel series of MSI1/MSI2 inhibitors is specific and active in biochemical, biophysical, and cellular assays. This study extends the paradigm of "hotspots" from protein-protein complexes to protein-RNA complexes, supports the "druggability" of RNA-binding protein surfaces, and represents one of the first rationally-designed inhibitors of non-enzymatic RNA-binding proteins. Owing to its simplicity and generality, we anticipate that this approach may also be used to develop inhibitors of many other RNA-binding proteins; we also consider the prospects of identifying potential off-target interactions by searching for other RBPs that recognize their cognate RNAs using similar interaction geometries. Beyond inhibitors, we also expect that compounds designed using this approach can serve as warheads for new PROTACs that selectively degrade RNA-binding proteins.
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Affiliation(s)
- Nan Bai
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia PA 19111
- Department of Molecular Biosciences, University of Kansas, Lawrence KS 66045
| | - Yusuf Adeshina
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia PA 19111
- Center for Computational Biology, University of Kansas, Lawrence KS 66045
| | - Igor Bychkov
- Division of Hematology/Oncology, Department of Medicine, Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Yan Xia
- Department of Molecular Biosciences, University of Kansas, Lawrence KS 66045
| | - Ragul Gowthaman
- Center for Computational Biology, University of Kansas, Lawrence KS 66045
| | - Sven A. Miller
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia PA 19111
| | - Abhishek K. Gupta
- Section of Hematology, Yale Cancer Center, New Haven CT 06520
- Department of Pathology, Yale University School of Medicine, New Haven CT 06520
| | - David K. Johnson
- Center for Computational Biology, University of Kansas, Lawrence KS 66045
| | - Lan Lan
- Department of Molecular Biosciences, University of Kansas, Lawrence KS 66045
| | - Erica A. Golemis
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia PA 19111
- Department of Cancer and Cellular Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140
| | - Petr B. Makhov
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia PA 19111
| | - Liang Xu
- Department of Molecular Biosciences, University of Kansas, Lawrence KS 66045
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City KS 66160
| | - Manoj M. Pillai
- Section of Hematology, Yale Cancer Center, New Haven CT 06520
- Department of Pathology, Yale University School of Medicine, New Haven CT 06520
| | - Yanis Boumber
- Division of Hematology/Oncology, Department of Medicine, Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - John Karanicolas
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia PA 19111
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, PA 19140
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Bai N, Adeshina Y, Bychkov I, Xia Y, Gowthaman R, Miller SA, Gupta AK, Johnson DK, Lan L, Golemis EA, Makhov PB, Xu L, Pillai MM, Boumber Y, Karanicolas J. Rationally designed inhibitors of the Musashi protein-RNA interaction by hotspot mimicry. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.09.523326. [PMID: 36711508 PMCID: PMC9882015 DOI: 10.1101/2023.01.09.523326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
RNA-binding proteins (RBPs) are key post-transcriptional regulators of gene expression, and thus underlie many important biological processes. Here, we developed a strategy that entails extracting a "hotspot pharmacophore" from the structure of a protein-RNA complex, to create a template for designing small-molecule inhibitors and for exploring the selectivity of the resulting inhibitors. We demonstrate this approach by designing inhibitors of Musashi proteins MSI1 and MSI2, key regulators of mRNA stability and translation that are upregulated in many cancers. We report this novel series of MSI1/MSI2 inhibitors is specific and active in biochemical, biophysical, and cellular assays. This study extends the paradigm of "hotspots" from protein-protein complexes to protein-RNA complexes, supports the "druggability" of RNA-binding protein surfaces, and represents one of the first rationally-designed inhibitors of non-enzymatic RNA-binding proteins. Owing to its simplicity and generality, we anticipate that this approach may also be used to develop inhibitors of many other RNA-binding proteins; we also consider the prospects of identifying potential off-target interactions by searching for other RBPs that recognize their cognate RNAs using similar interaction geometries. Beyond inhibitors, we also expect that compounds designed using this approach can serve as warheads for new PROTACs that selectively degrade RNA-binding proteins.
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Affiliation(s)
- Nan Bai
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia PA 19111
- Department of Molecular Biosciences, University of Kansas, Lawrence KS 66045
| | - Yusuf Adeshina
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia PA 19111
- Center for Computational Biology, University of Kansas, Lawrence KS 66045
| | - Igor Bychkov
- Division of Hematology/Oncology, Department of Medicine, Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Yan Xia
- Department of Molecular Biosciences, University of Kansas, Lawrence KS 66045
| | - Ragul Gowthaman
- Center for Computational Biology, University of Kansas, Lawrence KS 66045
| | - Sven A. Miller
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia PA 19111
| | | | - David K. Johnson
- Center for Computational Biology, University of Kansas, Lawrence KS 66045
| | - Lan Lan
- Department of Molecular Biosciences, University of Kansas, Lawrence KS 66045
| | - Erica A. Golemis
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia PA 19111
- Department of Cancer and Cellular Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140
| | - Petr B. Makhov
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia PA 19111
| | - Liang Xu
- Department of Molecular Biosciences, University of Kansas, Lawrence KS 66045
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City KS 66160
| | - Manoj M. Pillai
- Section of Hematology, Yale Cancer Center, New Haven CT 06520
- Department of Pathology, Yale University School of Medicine, New Haven CT 06520
| | - Yanis Boumber
- Division of Hematology/Oncology, Department of Medicine, Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - John Karanicolas
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia PA 19111
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, PA 19140
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Co-evolution of SNF spliceosomal proteins with their RNA targets in trans-splicing nematodes. Genetica 2016; 144:487-96. [PMID: 27450547 DOI: 10.1007/s10709-016-9918-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 07/15/2016] [Indexed: 10/21/2022]
Abstract
Although the mechanism of pre-mRNA splicing has been well characterized, the evolution of spliceosomal proteins is poorly understood. The U1A/U2B″/SNF family (hereafter referred to as the SNF family) of RNA binding spliceosomal proteins participates in both the U1 and U2 small interacting nuclear ribonucleoproteins (snRNPs). The highly constrained nature of this system has inhibited an analysis of co-evolutionary trends between the proteins and their RNA binding targets. Here we report accelerated sequence evolution in the SNF protein family in Phylum Nematoda, which has allowed an analysis of protein:RNA co-evolution. In a comparison of SNF genes from ecdysozoan species, we found a correlation between trans-splicing species (nematodes) and increased phylogenetic branch lengths of the SNF protein family, with respect to their sister clade Arthropoda. In particular, we found that nematodes (~70-80 % of pre-mRNAs are trans-spliced) have experienced higher rates of SNF sequence evolution than arthropods (predominantly cis-spliced) at both the nucleotide and amino acid levels. Interestingly, this increased evolutionary rate correlates with the reliance on trans-splicing by nematodes, which would alter the role of the SNF family of spliceosomal proteins. We mapped amino acid substitutions to functionally important regions of the SNF protein, specifically to sites that are predicted to disrupt protein:RNA and protein:protein interactions. Finally, we investigated SNF's RNA targets: the U1 and U2 snRNAs. Both are more divergent in nematodes than arthropods, suggesting the RNAs have co-evolved with SNF in order to maintain the necessarily high affinity interaction that has been characterized in other species.
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Delaney KJ, Williams SG, Lawler M, Hall KB. Climbing the vertebrate branch of U1A/U2B″ protein evolution. RNA (NEW YORK, N.Y.) 2014; 20:1035-1045. [PMID: 24840944 PMCID: PMC4114683 DOI: 10.1261/rna.044255.114] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 03/17/2014] [Indexed: 05/29/2023]
Abstract
In the vertebrate lineage of the U1A/U2B″/SNF protein family, the U1A and U2B″ proteins bind to RNA stem-loops in the U1 or U2 snRNPs, respectively. However, their specialization is fairly recent, as they evolved from a single ancestral protein. The progress of their specialization (subfunctionalization) can be monitored by the amino acid sequence changes that give rise to their modern RNA-binding specificity. Using ancestral sequence reconstruction to predict the intermediates on the evolutionary branch, a probable path of sequential changes is defined for U1A and U2B″. The RNA-binding affinity for U1A/U2B″ protein ancestors was measured using modern U1 and U2 snRNA stem-loops and RNA stem-loop variants to understand how the proteins' RNA specificities evolved.
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Affiliation(s)
- Kimberly J. Delaney
- Department of Biochemistry and Molecular Biophysics, Washington University Medical School, St. Louis, Missouri 63110, USA
| | - Sandra G. Williams
- Department of Biochemistry and Molecular Biophysics, Washington University Medical School, St. Louis, Missouri 63110, USA
| | - Mariah Lawler
- Department of Biochemistry and Molecular Biophysics, Washington University Medical School, St. Louis, Missouri 63110, USA
| | - Kathleen B. Hall
- Department of Biochemistry and Molecular Biophysics, Washington University Medical School, St. Louis, Missouri 63110, USA
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Blakeley BD, Shattuck J, Coates MB, Tran E, Laird-Offringa IA, McNaughton BR. Analysis of protein-RNA complexes involving a RNA recognition motif engineered to bind hairpins with seven- and eight-nucleotide loops. Biochemistry 2013; 52:4745-7. [PMID: 23806102 DOI: 10.1021/bi400801q] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
U1A binds U1hpII, a hairpin RNA with a 10-nucleotide loop. A U1A mutant (ΔK50ΔM51) binds U1hpII-derived hairpins with shorter loops, making it an interesting scaffold for engineering or evolving proteins that bind similarly sized disease-related hairpin RNAs. However, a more detailed understanding of complexes involving ΔK50ΔM51 is likely a prerequisite to generating such proteins. Toward this end, we measured mutational effects for complexes involving U1A ΔK50ΔM51 and U1hpII-derived hairpin RNAs with seven- or eight-nucleotide loops and identified contacts that are critical to the stabilization of these complexes. Our data provide valuable insight into sequence-selective recognition of seven- or eight-nucleotide loop hairpins by an engineered RNA binding protein.
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Affiliation(s)
- Brett D Blakeley
- Department of Chemistry and ‡Department of Biochemistry and Molecular Biology, Colorado State University , Fort Collins, Colorado 80523, United States
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Law MJ, Lee DS, Lee CS, Anglim PP, Haworth IS, Laird-Offringa IA. The role of the C-terminal helix of U1A protein in the interaction with U1hpII RNA. Nucleic Acids Res 2013; 41:7092-100. [PMID: 23703211 PMCID: PMC3737524 DOI: 10.1093/nar/gkt326] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Previous kinetic investigations of the N-terminal RNA Recognition Motif (RRM) domain of spliceosomal A protein of the U1 small nuclear ribonucleoprotein particle (U1A) interacting with its RNA target U1 hairpin II (U1hpII) provided experimental evidence for a ‘lure and lock’ model of binding. The final step of locking has been proposed to involve conformational changes in an α-helix immediately C-terminal to the RRM domain (helix C), which occludes the RNA binding surface in the unbound protein. Helix C must shift its position to accommodate RNA binding in the RNA–protein complex. This results in a new hydrophobic core, an intraprotein hydrogen bond and a quadruple stacking interaction between U1A and U1hpII. Here, we used a surface plasmon resonance-based biosensor to gain mechanistic insight into the role of helix C in mediating the interaction with U1hpII. Truncation, removal or disruption of the helix exposes the RNA-binding surface, resulting in an increase in the association rate, while simultaneously reducing the ability of the complex to lock, reflected in a loss of complex stability. Disruption of the quadruple stacking interaction has minor kinetic effects when compared with removal of the intraprotein hydrogen bonds. These data provide new insights into the mechanism whereby sequences C-terminal to an RRM can influence RNA binding.
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Affiliation(s)
- Michael J Law
- Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
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Alexander MR, Wheatley AK, Center RJ, Purcell DFJ. Efficient transcription through an intron requires the binding of an Sm-type U1 snRNP with intact stem loop II to the splice donor. Nucleic Acids Res 2010; 38:3041-53. [PMID: 20071748 PMCID: PMC2875018 DOI: 10.1093/nar/gkp1224] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The mechanism behind the positive action of introns upon transcription and the biological significance of this positive feedback remains unclear. Functional ablation of splice sites within an HIV-derived env cDNA significantly reduced transcription that was rescued by a U1 snRNA modified to bind to the mutated splice donor (SD). Using this model we further characterized both the U1 and pre-mRNA structural requirements for transcriptional enhancement. U1 snRNA rescued as a mature Sm-type snRNP with an intact stem loop II. Position and sequence context for U1-binding is crucial because a promoter proximal intron placed upstream of the mutated SD failed to rescue transcription. Furthermore, U1-rescue was independent of promoter and exon sequence and is partially replaced by the transcription elongation activator Tat, pointing to an intron-localized block in transcriptional elongation. Thus, transcriptional coupling of U1 snRNA binding to the SD may licence the polymerase for transcription through the intron.
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Affiliation(s)
- Marina R Alexander
- Department of Microbiology and Immunology, University of Melbourne, Melbourne 3010, Australia
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