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Giudice J, Jiang H. Splicing regulation through biomolecular condensates and membraneless organelles. Nat Rev Mol Cell Biol 2024:10.1038/s41580-024-00739-7. [PMID: 38773325 DOI: 10.1038/s41580-024-00739-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2024] [Indexed: 05/23/2024]
Abstract
Biomolecular condensates, sometimes also known as membraneless organelles (MLOs), can form through weak multivalent intermolecular interactions of proteins and nucleic acids, a process often associated with liquid-liquid phase separation. Biomolecular condensates are emerging as sites and regulatory platforms of vital cellular functions, including transcription and RNA processing. In the first part of this Review, we comprehensively discuss how alternative splicing regulates the formation and properties of condensates, and conversely the roles of biomolecular condensates in splicing regulation. In the second part, we focus on the spatial connection between splicing regulation and nuclear MLOs such as transcriptional condensates, splicing condensates and nuclear speckles. We then discuss key studies showing how splicing regulation through biomolecular condensates is implicated in human pathologies such as neurodegenerative diseases, different types of cancer, developmental disorders and cardiomyopathies, and conclude with a discussion of outstanding questions pertaining to the roles of condensates and MLOs in splicing regulation and how to experimentally study them.
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Affiliation(s)
- Jimena Giudice
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- McAllister Heart Institute, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Hao Jiang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, USA.
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2
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Lu X, Lu J, Li S, Feng S, Wang Y, Cui L. The Role of Liquid-Liquid Phase Separation in the Accumulation of Pathological Proteins: New Perspectives on the Mechanism of Neurodegenerative Diseases. Aging Dis 2024:AD.2024.0209. [PMID: 38739933 DOI: 10.14336/ad.2024.0209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 04/20/2024] [Indexed: 05/16/2024] Open
Abstract
It is widely accepted that living organisms form highly dynamic membrane-less organelles (MLOS) with various functions through phase separation, and the indispensable role that phase separation plays in the mechanisms of normal physiological functions and pathogenesis is gradually becoming clearer. Pathological aggregates, regarded as hallmarks of neurodegenerative diseases, have been revealed to be closely related to aberrant phase separation. Specific proteins are assembled into condensates and transform into insoluble inclusions through aberrant phase separation, contributing to the development of diseases. In this review, we present an overview of the progress of phase separation research, involving its biological mechanisms and the status of research in neurodegenerative diseases, focusing on five main disease-specific proteins, tau, TDP-43, FUS, α-Syn and HTT, and how exactly these proteins reside within dynamic liquid-like compartments and thus turn into solid deposits. Further studies will yield new perspectives for understanding the aggregation mechanisms and potential therapeutic strategies, and future research directions are anticipated.
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Affiliation(s)
- Xingyu Lu
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Jiongtong Lu
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Shengnan Li
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Sifan Feng
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Yan Wang
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Lili Cui
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
- The Marine Biomedical Research Institute of Guangdong, School of Ocean and Tropical Medicine, Guangdong Medical University, Zhanjiang, Guangdong, China
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3
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Freibaum BD, Messing J, Nakamura H, Yurtsever U, Wu J, Kim HJ, Hixon J, Lemieux RM, Duffner J, Huynh W, Wong K, White M, Lee C, Meyers RE, Parker R, Taylor JP. Identification of small molecule inhibitors of G3BP-driven stress granule formation. J Cell Biol 2024; 223:e202308083. [PMID: 38284934 PMCID: PMC10824102 DOI: 10.1083/jcb.202308083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 11/28/2023] [Accepted: 12/22/2023] [Indexed: 01/30/2024] Open
Abstract
Stress granule formation is triggered by the release of mRNAs from polysomes and is promoted by the action of the RNA-binding proteins G3BP1/2. Stress granules have been implicated in several disease states, including cancer and neurodegeneration. Consequently, compounds that limit stress granule formation or promote their dissolution have potential as both experimental tools and novel therapeutics. Herein, we describe two small molecules, G3BP inhibitor a and b (G3Ia and G3Ib), designed to bind to a specific pocket in G3BP1/2 that is targeted by viral inhibitors of G3BP1/2 function. In addition to disrupting the co-condensation of RNA, G3BP1, and caprin 1 in vitro, these compounds inhibit stress granule formation in cells treated prior to or concurrent with stress and dissolve pre-existing stress granules. These effects are consistent across multiple cell types and a variety of initiating stressors. Thus, these compounds represent powerful tools to probe the biology of stress granules and hold promise for therapeutic interventions designed to modulate stress granule formation.
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Affiliation(s)
- Brian D. Freibaum
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - James Messing
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Haruko Nakamura
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Ugur Yurtsever
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Jinjun Wu
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Hong Joo Kim
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | | | | | | | | | | | | | | | | | - Roy Parker
- Department of Biochemistry, University of Colorado, Boulder, CO, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - J. Paul Taylor
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
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4
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Jiang Y, Deane CM, Morris GM, O’Brien EP. It is theoretically possible to avoid misfolding into non-covalent lasso entanglements using small molecule drugs. PLoS Comput Biol 2024; 20:e1011901. [PMID: 38470915 PMCID: PMC10931463 DOI: 10.1371/journal.pcbi.1011901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 02/08/2024] [Indexed: 03/14/2024] Open
Abstract
A novel class of protein misfolding characterized by either the formation of non-native noncovalent lasso entanglements in the misfolded structure or loss of native entanglements has been predicted to exist and found circumstantial support through biochemical assays and limited-proteolysis mass spectrometry data. Here, we examine whether it is possible to design small molecule compounds that can bind to specific folding intermediates and thereby avoid these misfolded states in computer simulations under idealized conditions (perfect drug-binding specificity, zero promiscuity, and a smooth energy landscape). Studying two proteins, type III chloramphenicol acetyltransferase (CAT-III) and D-alanyl-D-alanine ligase B (DDLB), that were previously suggested to form soluble misfolded states through a mechanism involving a failure-to-form of native entanglements, we explore two different drug design strategies using coarse-grained structure-based models. The first strategy, in which the native entanglement is stabilized by drug binding, failed to decrease misfolding because it formed an alternative entanglement at a nearby region. The second strategy, in which a small molecule was designed to bind to a non-native tertiary structure and thereby destabilize the native entanglement, succeeded in decreasing misfolding and increasing the native state population. This strategy worked because destabilizing the entanglement loop provided more time for the threading segment to position itself correctly to be wrapped by the loop to form the native entanglement. Further, we computationally identified several FDA-approved drugs with the potential to bind these intermediate states and rescue misfolding in these proteins. This study suggests it is possible for small molecule drugs to prevent protein misfolding of this type.
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Affiliation(s)
- Yang Jiang
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Charlotte M. Deane
- Oxford Protein Informatics Group, Department of Statistics, University of Oxford, 24-29 St Giles’ Oxford, OX1 3LB United Kingdom
| | - Garrett M. Morris
- Oxford Protein Informatics Group, Department of Statistics, University of Oxford, 24-29 St Giles’ Oxford, OX1 3LB United Kingdom
| | - Edward P. O’Brien
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Bioinformatics and Genomics Graduate Program, The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Institute for Computational and Data Sciences, Pennsylvania State University, University Park, Pennsylvania, United States of America
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5
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Martin EW, Iserman C, Olety B, Mitrea DM, Klein IA. Biomolecular Condensates as Novel Antiviral Targets. J Mol Biol 2024; 436:168380. [PMID: 38061626 DOI: 10.1016/j.jmb.2023.168380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 11/23/2023] [Accepted: 11/30/2023] [Indexed: 12/24/2023]
Abstract
Viral infections pose a significant health risk worldwide. There is a pressing need for more effective antiviral drugs to combat emerging novel viruses and the reemergence of previously controlled viruses. Biomolecular condensates are crucial for viral replication and are promising targets for novel antiviral therapies. Herein, we review the role of biomolecular condensates in the viral replication cycle and discuss novel strategies to leverage condensate biology for antiviral drug discovery. Biomolecular condensates may also provide an opportunity to develop antivirals that are broad-spectrum or less prone to acquired drug resistance.
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6
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Freibaum BD, Messing J, Nakamura H, Yurtsever U, Wu J, Kim HJ, Hixon J, Lemieux R, Duffner J, Huynh W, Wong K, White M, Lee C, Meyers R, Parker R, Taylor JP. Identification of small molecule inhibitors of G3BP-driven stress granule formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.27.546770. [PMID: 37425931 PMCID: PMC10327151 DOI: 10.1101/2023.06.27.546770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Stress granule formation is triggered by the release of mRNAs from polysomes and is promoted by the action of the paralogs G3BP1 and G3BP2. G3BP1/2 proteins bind mRNAs and thereby promote the condensation of mRNPs into stress granules. Stress granules have been implicated in several disease states, including cancer and neurodegeneration. Consequently, compounds that limit stress granule formation or promote their dissolution have potential as both experimental tools and novel therapeutics. Herein, we describe two small molecules, referred to as G3BP inhibitor a and b (G3Ia and G3Ib), designed to bind to a specific pocket in G3BP1/2 that is known to be targeted by viral inhibitors of G3BP1/2 function. In addition to disrupting co-condensation of RNA, G3BP1, and caprin 1 in vitro, these compounds inhibit stress granule formation in cells treated prior to or concurrent with stress, and dissolve pre-existing stress granules when added to cells after stress granule formation. These effects are consistent across multiple cell types and a variety of initiating stressors. Thus, these compounds represent ideal tools to probe the biology of stress granules and hold promise for therapeutic interventions designed to modulate stress granule formation.
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Affiliation(s)
- Brian D Freibaum
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - James Messing
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Haruko Nakamura
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Ugur Yurtsever
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jinjun Wu
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Hong Joo Kim
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jeff Hixon
- Faze Medicines, Cambridge, Massachusetts, USA
| | | | - Jay Duffner
- Faze Medicines, Cambridge, Massachusetts, USA
| | | | - Kathy Wong
- Faze Medicines, Cambridge, Massachusetts, USA
| | | | | | | | - Roy Parker
- Department of Biochemistry, Howard Hughes Medical Institute, University of Colorado, Boulder, Colorado, USA
| | - J Paul Taylor
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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7
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Ciancone AM, Seo KW, Chen M, Borne AL, Libby AH, Bai DL, Kleiner RE, Hsu KL. Global Discovery of Covalent Modulators of Ribonucleoprotein Granules. J Am Chem Soc 2023; 145:11056-11066. [PMID: 37159397 PMCID: PMC10392812 DOI: 10.1021/jacs.3c00165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Stress granules (SGs) and processing-bodies (PBs, P-bodies) are ubiquitous and widely studied ribonucleoprotein (RNP) granules involved in cellular stress response, viral infection, and the tumor microenvironment. While proteomic and transcriptomic investigations of SGs and PBs have provided insights into molecular composition, chemical tools to probe and modulate RNP granules remain lacking. Herein, we combine an immunofluorescence (IF)-based phenotypic screen with chemoproteomics to identify sulfonyl-triazoles (SuTEx) capable of preventing or inducing SG and PB formation through liganding of tyrosine (Tyr) and lysine (Lys) sites in stressed cells. Liganded sites were enriched for RNA-binding and protein-protein interaction (PPI) domains, including several sites found in RNP granule-forming proteins. Among these, we functionally validate G3BP1 Y40, located in the NTF2 dimerization domain, as a ligandable site that can disrupt arsenite-induced SG formation in cells. In summary, we present a chemical strategy for the systematic discovery of condensate-modulating covalent small molecules.
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Affiliation(s)
- Anthony M. Ciancone
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Kyung W. Seo
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Miaomiao Chen
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Adam L. Borne
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, United States
| | - Adam H. Libby
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
- University of Virginia Cancer Center, University of Virginia, Charlottesville, VA 22903, USA
| | - Dina L. Bai
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Ralph E. Kleiner
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Ku-Lung Hsu
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, United States
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908, United States
- University of Virginia Cancer Center, University of Virginia, Charlottesville, VA 22903, USA
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8
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Bauer KE, de Queiroz BR, Kiebler MA, Besse F. RNA granules in neuronal plasticity and disease. Trends Neurosci 2023:S0166-2236(23)00104-2. [PMID: 37202301 DOI: 10.1016/j.tins.2023.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/11/2023] [Accepted: 04/16/2023] [Indexed: 05/20/2023]
Abstract
RNA granules are dynamic entities controlling the spatiotemporal distribution and translation of RNA molecules. In neurons, a variety of RNA granules exist both in the soma and in cellular processes. They contain transcripts encoding signaling and synaptic proteins as well as RNA-binding proteins causally linked to several neurological disorders. In this review, we highlight that neuronal RNA granules exhibit properties of biomolecular condensates that are regulated upon maturation and physiological aging and how they are reversibly remodeled in response to neuronal activity to control local protein synthesis and ultimately synaptic plasticity. Moreover, we propose a framework of how neuronal RNA granules mature over time in healthy conditions and how they transition into pathological inclusions in the context of late-onset neurodegenerative diseases.
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Affiliation(s)
- Karl E Bauer
- Biomedical Center (BMC), Department of Anatomy and Cell Biology, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Bruna R de Queiroz
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - Michael A Kiebler
- Biomedical Center (BMC), Department of Anatomy and Cell Biology, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany.
| | - Florence Besse
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France.
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Macromolecular Crowding Is Surprisingly Unable to Deform the Structure of a Model Biomolecular Condensate. BIOLOGY 2023; 12:biology12020181. [PMID: 36829460 PMCID: PMC9952705 DOI: 10.3390/biology12020181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 01/27/2023]
Abstract
The crowded interior of a living cell makes performing experiments on simpler in vitro systems attractive. Although these reveal interesting phenomena, their biological relevance can be questionable. A topical example is the phase separation of intrinsically disordered proteins into biomolecular condensates, which is proposed to underlie the membrane-less compartmentalization of many cellular functions. How a cell reliably controls biochemical reactions in compartments open to the compositionally-varying cytoplasm is an important question for understanding cellular homeostasis. Computer simulations are often used to study the phase behavior of model biomolecular condensates, but the number of relevant parameters increases as the number of protein components increases. It is unfeasible to exhaustively simulate such models for all parameter combinations, although interesting phenomena are almost certainly hidden in their high-dimensional parameter space. Here, we have studied the phase behavior of a model biomolecular condensate in the presence of a polymeric crowding agent. We used a novel compute framework to execute dozens of simultaneous simulations spanning the protein/crowder concentration space. We then combined the results into a graphical representation for human interpretation, which provided an efficient way to search the model's high-dimensional parameter space. We found that steric repulsion from the crowder drives a near-critical system across the phase boundary, but the molecular arrangement within the resulting biomolecular condensate is rather insensitive to the crowder concentration and molecular weight. We propose that a cell may use the local cytoplasmic concentration to assist the formation of biomolecular condensates, while relying on the dense phase to reliably provide a stable, structured, fluid milieu for cellular biochemistry despite being open to its changing environment.
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Secretory Phospholipases A2, from Snakebite Envenoming to a Myriad of Inflammation Associated Human Diseases-What Is the Secret of Their Activity? Int J Mol Sci 2023; 24:ijms24021579. [PMID: 36675102 PMCID: PMC9863470 DOI: 10.3390/ijms24021579] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/05/2023] [Accepted: 01/11/2023] [Indexed: 01/15/2023] Open
Abstract
Secreted phospholipases of type A2 (sPLA2s) are proteins of 14-16 kDa present in mammals in different forms and at different body sites. They are involved in lipid transformation processes, and consequently in various immune, inflammatory, and metabolic processes. sPLA2s are also major components of snake venoms, endowed with various toxic and pharmacological properties. The activity of sPLA2s is not limited to the enzymatic one but, through interaction with different types of molecules, they exert other activities that are still little known and explored, both outside and inside the cells, as they can be endocytosed. The aim of this review is to analyze three features of sPLA2s, yet under-explored, knowledge of which could be crucial to understanding the activity of these proteins. The first feature is their disulphide bridge pattern, which has always been considered immutable and necessary for their stability, but which might instead be modulable. The second characteristic is their ability to undergo various post-translational modifications that would control their interaction with other molecules. The third feature is their ability to participate in active molecular condensates both on the surface and within the cell. Finally, the implications of these features in the design of anti-inflammatory drugs are discussed.
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