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Maffucci T, Falasca M. Signalling Properties of Inositol Polyphosphates. Molecules 2020; 25:molecules25225281. [PMID: 33198256 PMCID: PMC7696153 DOI: 10.3390/molecules25225281] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 12/16/2022] Open
Abstract
Several studies have identified specific signalling functions for inositol polyphosphates (IPs) in different cell types and have led to the accumulation of new information regarding their cellular roles as well as new insights into their cellular production. These studies have revealed that interaction of IPs with several proteins is critical for stabilization of protein complexes and for modulation of enzymatic activity. This has not only revealed their importance in regulation of several cellular processes but it has also highlighted the possibility of new pharmacological interventions in multiple diseases, including cancer. In this review, we describe some of the intracellular roles of IPs and we discuss the pharmacological opportunities that modulation of IPs levels can provide.
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Affiliation(s)
- Tania Maffucci
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
- Correspondence: (T.M.); (M.F.); Tel.: +61-08-92669712 (M.F.)
| | - Marco Falasca
- School of Pharmacy and Biomedical Sciences, CHIRI, Curtin University, Perth 6102, Australia
- Correspondence: (T.M.); (M.F.); Tel.: +61-08-92669712 (M.F.)
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Brehm MA, Klemm U, Rehbach C, Erdmann N, Kolšek K, Lin H, Aponte-Santamaría C, Gräter F, Rauch BH, Riley AM, Mayr GW, Potter BVL, Windhorst S. Inositol hexakisphosphate increases the size of platelet aggregates. Biochem Pharmacol 2018; 161:14-25. [PMID: 30557554 PMCID: PMC6372069 DOI: 10.1016/j.bcp.2018.12.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 12/13/2018] [Indexed: 12/28/2022]
Abstract
The inositol phosphates, InsP5 and InsP6, have recently been identified as binding partners of fibrinogen, which is critically involved in hemostasis by crosslinking activated platelets at sites of vascular injury. Here, we investigated the putative physiological role of this interaction and found that platelets increase their InsP6 concentration upon stimulation with the PLC-activating agonists thrombin, collagen I and ADP and present a fraction of it at the outer plasma membrane. Cone and plate analysis in whole blood revealed that InsP6 specifically increases platelet aggregate size. This effect is fibrinogen-dependent, since it is inhibited by an antibody that blocks fibrinogen binding to platelets. Furthermore, InsP6 has only an effect on aggregate size of washed platelets when fibrinogen is present, while it has no influence in presence of von Willebrand factor or collagen. By employing blind docking studies we predicted the binding site for InsP6 at the bundle between the γ and β helical subunit of fibrinogen. Since InsP6 is unable to directly activate platelets and it did not exhibit an effect on thrombin formation or fibrin structure, our data indicate that InsP6 might be a hemostatic agent that is produced by platelets upon stimulation with PLC-activating agonists to promote platelet aggregation by supporting crosslinking of fibrinogen and activated platelets.
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Affiliation(s)
- Maria A Brehm
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ulrike Klemm
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christoph Rehbach
- Department of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany
| | - Nina Erdmann
- Department of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany
| | - Katra Kolšek
- Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Hongying Lin
- Department of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany
| | | | - Frauke Gräter
- Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Bernhard H Rauch
- Institute of Pharmacology, University Medicine Greifswald, Ernst-Moritz-Arndt University, Felix-Hausdorff-Str. 3, 17487 Greifswald, Germany
| | - Andrew M Riley
- Medicinal Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Georg W Mayr
- Department of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany
| | - Barry V L Potter
- Medicinal Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Sabine Windhorst
- Department of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany.
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