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Ramsey KM, Barrick D. Unraveling paralog-specific Notch signaling through thermodynamics of ternary complex formation and transcriptional activation of chimeric receptors. Protein Sci 2024; 33:e4947. [PMID: 38511488 PMCID: PMC10962485 DOI: 10.1002/pro.4947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 02/07/2024] [Accepted: 02/11/2024] [Indexed: 03/22/2024]
Abstract
Notch signaling in humans is mediated by four paralogous receptors that share conserved architectures and possess overlapping, yet non-redundant functions. The receptors share a canonical activation pathway wherein upon extracellular ligand binding, the Notch intracellular domain (NICD) is cleaved from the membrane and translocates to the nucleus where its N-terminal RBP-j-associated molecule (RAM) region and ankyrin repeat (ANK) domain bind transcription factor CSL and recruit co-activator Mastermind-like-1 (MAML1) to activate transcription. However, different paralogs can lead to distinct outcomes. To better understand paralog-specific differences in Notch signaling, we performed a thermodynamic analysis of the Notch transcriptional activation complexes for all four Notch paralogs using isothermal titration calorimetry. Using chimeric constructs, we find that the RAM region is the primary determinant of stability of binary RAMANK:CSL complexes, and that the ANK regions are largely the determinants of MAML1 binding to pre-formed RAMANK:CSL complexes. Free energies of these binding reactions (ΔGRA and ΔGMAML) vary among the four Notch paralogs, although variations for Notch2, 3, and 4 offset in the free energy of the ternary complex (ΔGTC, where ΔGTC = ΔGRA + ΔGMAML). To probe how these affinity differences affect Notch signaling, we performed transcriptional activation assays with the paralogous and chimeric NICDs, and analyzed the results with an independent multiplicative model that quantifies contributions of the paralogous RAM, ANK, and C-terminal regions (CTR) to activation. This analysis shows that transcription activation correlates with ΔGTC, but that activation is further modified by CTR identity in a paralog-specific way.
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Affiliation(s)
- Kristen M. Ramsey
- T.C. Jenkins Department of BiophysicsJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Doug Barrick
- T.C. Jenkins Department of BiophysicsJohns Hopkins UniversityBaltimoreMarylandUSA
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Verma S, Giagnocavo SD, Curtin MC, Arumugam M, Osburn-Staker SM, Wang G, Atkinson A, Nix DA, Lum DH, Cox JE, Hilgendorf KI. Zinc Alpha-2-Glycoprotein (ZAG/AZGP1) secreted by triple-negative breast cancer promotes tumor microenvironment fibrosis. bioRxiv 2024:2024.03.04.583349. [PMID: 38496643 PMCID: PMC10942361 DOI: 10.1101/2024.03.04.583349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Obesity is a predisposition factor for breast cancer, suggesting a localized, reciprocal interaction between breast cancer cells and the surrounding mammary white adipose tissue. To investigate how breast cancer cells alter the composition and function of adipose tissue, we screened the secretomes of ten human breast cancer cell lines for the ability to modulate the differentiation of adipocyte stem and progenitor cells (ASPC). The screen identified a key adipogenic modulator, Zinc Alpha-2-Glycoprotein (ZAG/AZGP1), secreted by triple-negative breast cancer (TNBC) cells. TNBC-secreted ZAG inhibits adipogenesis and instead induces the expression of fibrotic genes. Accordingly, depletion of ZAG in TNBC cells attenuates fibrosis in white adipose tissue and inhibits tumor growth. Further, high expression of ZAG in TNBC patients, but not other clinical subtypes of breast cancer, is linked to poor prognosis. Our findings suggest a role of TNBC-secreted ZAG in promoting the transdifferentiation of ASPCs into cancer-associated fibroblasts to support tumorigenesis.
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Affiliation(s)
- Surbhi Verma
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | | | - Meghan C Curtin
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Menusha Arumugam
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Sandra M Osburn-Staker
- Metabolomics, Proteomics and Mass Spectrometry Core, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Guoying Wang
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - Aaron Atkinson
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - David A Nix
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - David H Lum
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - James E Cox
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
- Metabolomics, Proteomics and Mass Spectrometry Core, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Keren I Hilgendorf
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
- Lead contact:
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Kotliar IB, Bendes A, Dahl L, Chen Y, Saarinen M, Ceraudo E, Dodig-Crnković T, Uhlén M, Svenningsson P, Schwenk JM, Sakmar TP. Expanding the GPCR-RAMP interactome. bioRxiv 2023:2023.11.22.568247. [PMID: 38045268 PMCID: PMC10690247 DOI: 10.1101/2023.11.22.568247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Receptor activity-modifying proteins (RAMPs) can form complexes with G protein-coupled receptors (GPCRs) and regulate their cellular trafficking and pharmacology. RAMP interactions have been identified for about 50 GPCRs, but only a few GPCR-RAMP complexes have been studied in detail. To elucidate a complete interactome between GPCRs and the three RAMPs, we developed a customized library of 215 Dual Epitope-Tagged (DuET) GPCRs representing all GPCR subfamilies. Using a multiplexed suspension bead array (SBA) assay, we identified 122 GPCRs that showed strong evidence for interaction with at least one RAMP. We screened for native interactions in three cell lines and found 23 GPCRs that formed complexes with RAMPs. Mapping the GPCR-RAMP interactome expands the current system-wide functional characterization of RAMP-interacting GPCRs to inform the design of selective GPCR-targeted therapeutics. One-Sentence Summary Novel complexes between G protein-coupled receptors and interacting proteins point to a system-wide regulation of GPCR function.
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Pouliou M, Koutsi MA, Champezou L, Giannopoulou AI, Vatsellas G, Piperi C, Agelopoulos M. MYCN Amplifications and Metabolic Rewiring in Neuroblastoma. Cancers (Basel) 2023; 15:4803. [PMID: 37835497 PMCID: PMC10571721 DOI: 10.3390/cancers15194803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/20/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
Cancer is a disease caused by (epi)genomic and gene expression abnormalities and characterized by metabolic phenotypes that are substantially different from the normal phenotypes of the tissues of origin. Metabolic reprogramming is one of the key features of tumors, including those established in the human nervous system. In this work, we emphasize a well-known cancerous genomic alteration: the amplification of MYCN and its downstream effects in neuroblastoma phenotype evolution. Herein, we extend our previous computational biology investigations by conducting an integrative workflow applied to published genomics datasets and comprehensively assess the impact of MYCN amplification in the upregulation of metabolism-related transcription factor (TF)-encoding genes in neuroblastoma cells. The results obtained first emphasized overexpressed TFs, and subsequently those committed in metabolic cellular processes, as validated by gene ontology analyses (GOs) and literature curation. Several genes encoding for those TFs were investigated at the mechanistic and regulatory levels by conducting further omics-based computational biology assessments applied on published ChIP-seq datasets retrieved from MYCN-amplified- and MYCN-enforced-overexpression within in vivo systems of study. Hence, we approached the mechanistic interrelationship between amplified MYCN and overexpression of metabolism-related TFs in neuroblastoma and showed that many are direct targets of MYCN in an amplification-inducible fashion. These results illuminate how MYCN executes its regulatory underpinnings on metabolic processes in neuroblastoma.
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Affiliation(s)
- Marialena Pouliou
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, 4 Soranou Ephessiou St., 11527 Athens, Greece; (M.P.); (M.A.K.); (L.C.); (G.V.)
| | - Marianna A. Koutsi
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, 4 Soranou Ephessiou St., 11527 Athens, Greece; (M.P.); (M.A.K.); (L.C.); (G.V.)
| | - Lydia Champezou
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, 4 Soranou Ephessiou St., 11527 Athens, Greece; (M.P.); (M.A.K.); (L.C.); (G.V.)
| | - Angeliki-Ioanna Giannopoulou
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 75 M. Asias Street Bldg 16, 11527 Athens, Greece;
| | - Giannis Vatsellas
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, 4 Soranou Ephessiou St., 11527 Athens, Greece; (M.P.); (M.A.K.); (L.C.); (G.V.)
| | - Christina Piperi
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 75 M. Asias Street Bldg 16, 11527 Athens, Greece;
| | - Marios Agelopoulos
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, 4 Soranou Ephessiou St., 11527 Athens, Greece; (M.P.); (M.A.K.); (L.C.); (G.V.)
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