Silas Boye Nissen
Postdoctoral Scholar, Pathology
All Publications
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AlphaFold2 enables accurate deorphanization of ligands to single-pass receptors.
Cell systems
2024
Abstract
Secreted proteins play crucial roles in paracrine and endocrine signaling; however, identifying ligand-receptor interactions remains challenging. Here, we benchmarked AlphaFold2 (AF2) as a screening approach to identify extracellular ligands to single-pass transmembrane receptors. Key to the approach is the optimization of AF2 input and output for screening ligands against receptors to predict the most probable ligand-receptor interactions. The predictions were performed on ligand-receptor pairs not used for AF2 training. We demonstrate high discriminatory power and a success rate of close to 90% for known ligand-receptor pairs and 50% for a diverse set of experimentally validated interactions. Further, we show that screen accuracy does not correlate linearly with prediction of ligand-receptor interaction. These results demonstrate a proof of concept of a rapid and accurate screening platform to predict high-confidence cell-surface receptors for a diverse set of ligands by structural binding prediction, with potentially wide applicability for the understanding of cell-cell communication.
View details for DOI 10.1016/j.cels.2024.10.004
View details for PubMedID 39541981
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Cluster Assembly Dynamics Drive Fidelity of Planar Cell Polarity Polarization.
bioRxiv : the preprint server for biology
2024
Abstract
The planar cell polarity (PCP) signaling pathway polarizes epithelial cells in the tissue plane by segregating distinct molecular subcomplexes to opposite sides of each cell, where they interact across intercellular junctions to form asymmetric clusters. The role of clustering in this process is unknown. We hypothesized that protein cluster size distributions could be used to infer the underlying molecular dynamics and function of cluster assembly and polarization. We developed a method to count the number of monomers of core PCP proteins within individual clusters in live animals, and made measurements over time and space in wild type and in strategically chosen mutants. The data demonstrate that clustering is required for polarization, and together with mathematical modeling provide evidence that cluster assembly dynamics dictate that larger clusters are more likely to be strongly asymmetric and correctly oriented. We propose that cluster assembly dynamics thereby drive fidelity of cell- and tissue-level polarization.
View details for DOI 10.1101/2024.10.21.619498
View details for PubMedID 39484486
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Protein phosphatase 1 regulates core PCP signaling.
EMBO reports
2023: e56997
Abstract
Planar cell polarity (PCP) signaling polarizes epithelial cells within the plane of an epithelium. Core PCP signaling components adopt asymmetric subcellular localizations within cells to both polarize and coordinate polarity between cells. Achieving subcellular asymmetry requires additional effectors, including some mediating post-translational modifications of core components. Identification of such proteins is challenging due to pleiotropy. We used mass spectrometry-based proximity labeling proteomics to identify such regulators in the Drosophila wing. We identified the catalytic subunit of protein phosphatase1, Pp1-87B, and show that it regulates core protein polarization. Pp1-87B interacts with the core protein Van Gogh and at least one serine/threonine kinase, Dco/CKIε, that is known to regulate PCP. Pp1-87B modulates Van Gogh subcellular localization and directs its dephosphorylation in vivo. PNUTS, a Pp1 regulatory subunit, also modulates PCP. While the direct substrate(s) of Pp1-87B in control of PCP is not known, our data support the model that cycling between phosphorylated and unphosphorylated forms of one or more core PCP components may regulate acquisition of asymmetry. Finally, our screen serves as a resource for identifying additional regulators of PCP signaling.
View details for DOI 10.15252/embr.202356997
View details for PubMedID 37975164
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Cell autonomous polarization by the planar cell polarity signaling pathway.
bioRxiv : the preprint server for biology
2023
Abstract
Planar Cell Polarity (PCP) signaling polarizes epithelial cells in a plane orthogonal to their apical-basal axis. A core PCP signaling module both generates molecular asymmetry within cells and coordinates the direction of polarization between neighboring cells. Two subcomplexes of core proteins segregate to opposite sides of the cell, defining a polarity axis. Homodimers of the atypical cadherin Flamingo are thought to be the scaffold upon which these subcomplexes assemble and are required for intercellular polarity signaling. The central role for Flamingo homodimers in scaffolding and intercellular communication suggests that cells in which intercellular signaling via Flamingo is disabled should fail to polarize. We show that cells lacking Flamingo, or bearing a truncated Flamingo that cannot homodimerize do in fact polarize. Cell polarization requires both positive and negative feedback, and in a multicellular tissue, feedback might involve both intracellular and intercellular pathways. We identify positive and negative feedback pathways that operate cell autonomously to drive polarization.
View details for DOI 10.1101/2023.09.26.559449
View details for PubMedID 37808631
View details for PubMedCentralID PMC10557733
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Protein phosphatase 1 regulates core PCP signaling.
bioRxiv : the preprint server for biology
2023
Abstract
PCP signaling polarizes epithelial cells within the plane of an epithelium. Core PCP signaling components adopt asymmetric subcellular localizations within cells to both polarize and coordinate polarity between cells. Achieving subcellular asymmetry requires additional effectors, including some mediating post-translational modifications of core components. Identification of such proteins is challenging due to pleiotropy. We used mass spectrometry-based proximity labeling proteomics to identify such regulators in the Drosophila wing. We identified the catalytic subunit of Protein Phosphatase1, Pp1-87B, and show that it regulates core protein polarization. Pp1-87B interacts with the core protein Van Gogh and at least one Serine/Threonine kinase, Dco/CKIε, that is known to regulate PCP. Pp1-87B modulates Van Gogh subcellular localization and directs its dephosphorylation in vivo. PNUTS, a Pp1 regulatory subunit, also modulates PCP. While the direct substrate(s) of Pp1-87B in control of PCP is not known, our data support the model that cycling between phosphorylated and unphosphorylated forms of one or more core PCP components may regulate acquisition of asymmetry. Finally, our screen serves as a resource for identifying additional regulators of PCP signaling.
View details for DOI 10.1101/2023.09.12.556998
View details for PubMedID 37745534
View details for PubMedCentralID PMC10515792
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Rapid and accurate deorphanization of ligand-receptor pairs using AlphaFold.
bioRxiv : the preprint server for biology
2023
Abstract
Secreted proteins are extracellular ligands that play key roles in paracrine and endocrine signaling, classically by binding cell surface receptors. Experimental assays to identify new extracellular ligand-receptor interactions are challenging, which has hampered the rate of novel ligand discovery. Here, using AlphaFold-multimer, we developed and applied an approach for extracellular ligand-binding prediction to a structural library of 1,108 single-pass transmembrane receptors. We demonstrate high discriminatory power and a success rate of close to 90 % for known ligand-receptor pairs where no a priori structural information is required. Importantly, the prediction was performed on de novo ligand-receptor pairs not used for AlphaFold training and validated against experimental structures. These results demonstrate proof-of-concept of a rapid and accurate computational resource to predict high-confidence cell-surface receptors for a diverse set of ligands by structural binding prediction, with potentially wide applicability for the understanding of cell-cell communication.
View details for DOI 10.1101/2023.03.16.531341
View details for PubMedID 36993313
View details for PubMedCentralID PMC10055078
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Molecular mechanism of core planar cell polarity complex function elucidated with single-molecule methods
CELL PRESS. 2023: 59A
View details for Web of Science ID 000989629700289
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Mapping transcriptional heterogeneity and metabolic networks in fatty livers at single-cell resolution.
iScience
2023; 26 (1): 105802
Abstract
Non-alcoholic fatty liver disease is a heterogeneous disease with unclear underlying molecular mechanisms. Here, we perform single-cell RNA sequencing of hepatocytes and hepatic non-parenchymal cells to map the lipid signatures in mice with non-alcoholic fatty liver disease (NAFLD). We uncover previously unidentified clusters of hepatocytes characterized by either high or low srebp1 expression. Surprisingly, the canonical lipid synthesis driver Srebp1 is not predictive of hepatic lipid accumulation, suggestive of other drivers of lipid metabolism. By combining transcriptional data at single-cell resolution with computational network analyses, we find that NAFLD is associated with high constitutive androstane receptor (CAR) expression. Mechanistically, CAR interacts with four functional modules: cholesterol homeostasis, bile acid metabolism, fatty acid metabolism, and estrogen response. Nuclear expression of CAR positively correlates with steatohepatitis in human livers. These findings demonstrate significant cellular differences in lipid signatures and identify functional networks linked to hepatic steatosis in mice and humans.
View details for DOI 10.1016/j.isci.2022.105802
View details for PubMedID 36636354
View details for PubMedCentralID PMC9830221
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Transcriptional heterogeneity and cell cycle regulation as central determinants of Primitive Endoderm priming
ELIFE
2022; 11
View details for DOI 10.7554/eLife.78967
View details for Web of Science ID 000846816900001