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Krzyzanowski A, Gasper R, Adihou H, Hart P', Waldmann H. Biochemical Investigation of the Interaction of pICln, RioK1 and COPR5 with the PRMT5-MEP50 Complex. Chembiochem 2021; 22:1908-1914. [PMID: 33624332 PMCID: PMC8252068 DOI: 10.1002/cbic.202100079] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Indexed: 01/02/2023]
Abstract
The PRMT5–MEP50 methyltransferase complex plays a key role in various cancers and is regulated by different protein–protein interactions. Several proteins have been reported to act as adaptor proteins that recruit substrate proteins to the active site of PRMT5 for the methylation of arginine residues. To define the interaction between these adaptor proteins and PRMT5, we employed peptide truncation and mutation studies and prepared truncated protein constructs. We report the characterisation of the interface between the TIM barrel of PRMT5 and the adaptor proteins pICln, RioK1 and COPR5, and identify the consensus amino acid sequence GQF[D/E]DA[E/D] involved in binding. Protein crystallography revealed that the RioK1 derived peptide interacts with a novel PPI site.
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Affiliation(s)
- Adrian Krzyzanowski
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany.,Faculty of Chemistry, Chemical Biology, Technical University Dortmund, Otto-Hahn-Strasse 6, 44221, Dortmund, Germany
| | - Raphael Gasper
- Crystallography and Biophysics Unit, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
| | - Hélène Adihou
- AstraZeneca MPI Satellite Unit, Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany.,Medicinal Chemistry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Otto-Hahn-Strasse 11, 44227, Gothenburg, Sweden
| | - Peter 't Hart
- Chemical Genomics Centre of the Max Planck Society, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
| | - Herbert Waldmann
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany.,Faculty of Chemistry, Chemical Biology, Technical University Dortmund, Otto-Hahn-Strasse 6, 44221, Dortmund, Germany
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2
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Bazzini C, Benedetti L, Civello D, Zanoni C, Rossetti V, Marchesi D, Garavaglia ML, Paulmichl M, Francolini M, Meyer G, Rodighiero S. ICln: a new regulator of non-erythroid 4.1R localisation and function. PLoS One 2014; 9:e108826. [PMID: 25295618 PMCID: PMC4189953 DOI: 10.1371/journal.pone.0108826] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 08/27/2014] [Indexed: 01/12/2023] Open
Abstract
To optimise the efficiency of cell machinery, cells can use the same protein (often called a hub protein) to participate in different cell functions by simply changing its target molecules. There are large data sets describing protein-protein interactions (“interactome”) but they frequently fail to consider the functional significance of the interactions themselves. We studied the interaction between two potential hub proteins, ICln and 4.1R (in the form of its two splicing variants 4.1R80 and 4.1R135), which are involved in such crucial cell functions as proliferation, RNA processing, cytoskeleton organisation and volume regulation. The sub-cellular localisation and role of native and chimeric 4.1R over-expressed proteins in human embryonic kidney (HEK) 293 cells were examined. ICln interacts with both 4.1R80 and 4.1R135 and its over-expression displaces 4.1R from the membrane regions, thus affecting 4.1R interaction with ß-actin. It was found that 4.1R80 and 4.1R135 are differently involved in regulating the swelling activated anion current (ICl,swell) upon hypotonic shock, a condition under which both isoforms are dislocated from the membrane region and thus contribute to ICl,swell current regulation. Both 4.1R isoforms are also differently involved in regulating cell morphology, and ICln counteracts their effects. The findings of this study confirm that 4.1R plays a role in cell volume regulation and cell morphology and indicate that ICln is a new negative regulator of 4.1R functions.
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Affiliation(s)
- Claudia Bazzini
- Department of Biosciences, University of Milan, Milan, Italy
| | - Lorena Benedetti
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
- Fondazione Filarete for Biosciences and Innovation, Milan, Italy
| | - Davide Civello
- Department of Biosciences, University of Milan, Milan, Italy
| | - Chiara Zanoni
- Pharmaceutical Sciences Department (DISFARM), University of Milan, Milan, Italy
| | | | - Davide Marchesi
- Fondazione Filarete for Biosciences and Innovation, Milan, Italy
| | | | - Markus Paulmichl
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | - Maura Francolini
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
- Fondazione Filarete for Biosciences and Innovation, Milan, Italy
| | - Giuliano Meyer
- Department of Biosciences, University of Milan, Milan, Italy
| | - Simona Rodighiero
- Fondazione Filarete for Biosciences and Innovation, Milan, Italy
- * E-mail:
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3
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Schedlbauer A, Gandini R, Kontaxis G, Paulmichl M, Furst J, Konrat R. The C-terminus of ICln is natively disordered but displays local structural preformation. Cell Physiol Biochem 2011; 28:1203-10. [PMID: 22179008 DOI: 10.1159/000335852] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2011] [Indexed: 11/19/2022] Open
Abstract
ICln is a vital, ubiquitously expressed protein with roles in cell volume regulation, angiogenesis, cell morphology, activation of platelets and RNA processing. In previous work we have determined the 3D structure of the N-terminus of ICln (residues 1-159), which folds into a PH-like domain followed by an unstructured region (residues H134 - Q159) containing protein-protein interaction sites. Here we present sequence-specific resonance assignments of the C-terminus (residues Q159 - H235) of ICln by NMR, and show that this region of the protein is intrinsically unstructured. By applying (13)Cα- (13)Cβ secondary chemical shifts to detect possible preferences for secondary structure elements we show that the C-terminus of ICln adopts a preferred α-helical organization between residues E170 and E187, and exists preferentially in extended conformations (β-strands) between residues D161 to Y168 and E217 to T223.
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Pesiridis GS, Diamond E, Van Duyne GD. Role of pICLn in methylation of Sm proteins by PRMT5. J Biol Chem 2009; 284:21347-59. [PMID: 19520849 PMCID: PMC2755859 DOI: 10.1074/jbc.m109.015578] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 06/10/2009] [Indexed: 11/25/2022] Open
Abstract
pICln is an essential, highly conserved 26-kDa protein whose functions include binding to Sm proteins in the cytoplasm of human cells and mediating the ordered and regulated assembly of the cell's RNA-splicing machinery by the survival motor neurons complex. pICln also interacts with PRMT5, the enzyme responsible for generating symmetric dimethylarginine modifications on the carboxyl-terminal regions of three of the canonical Sm proteins. To better understand the role of pICln in these cellular processes, we have investigated the properties of pICln and pICln.Sm complexes and the effects that pICln has on the methyltransferase activity of PRMT5. We find that pICln is a monomer in solution, binds with high affinity (K(d) approximately 160 nm) to SmD3-SmB, and forms 1:1 complexes with Sm proteins and Sm protein subcomplexes. The data support an end-capping model of pICln binding that supports current views of how pICln prevents Sm oligomerization on illicit RNA substrates. We have found that by co-expression with pICln, recombinant PRMT5 can be produced in a soluble, active form. PRMT5 alone has promiscuous activity toward a variety of known substrates. In the presence of pICln, however, PRMT5 methylation of Sm proteins is stimulated, but methylation of histones is inhibited. We have also found that mutations in pICln that do not affect Sm protein binding can still have a profound effect on the methyltransferase activity of the PRMT5 complex. Together, the data provide insights into pICln function and represent an important starting point for biochemical analyses of PRMT5.
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Affiliation(s)
- G. Scott Pesiridis
- From the Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Evan Diamond
- From the Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Gregory D. Van Duyne
- From the Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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5
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Fürst J, Bottà G, Saino S, Dopinto S, Gandini R, Dossena S, Vezzoli V, Rodighiero S, Bazzini C, Garavaglia ML, Meyer G, Jakab M, Ritter M, Wappl-Kornherr E, Paulmichl M. The ICln interactome. Acta Physiol (Oxf) 2006; 187:43-9. [PMID: 16734741 DOI: 10.1111/j.1748-1716.2006.01549.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The many different functional phenotypes described in mammalian cells can only be explained by an intense interaction of the underlying proteins, substantiated by the fact that the number of independently expressed proteins in living cells seems not to exceed 25 K, a number way too small to explain the >250 K different phenotypes on a one-protein-one-function base. Therefore, the study of the interactome of the different proteins is of utmost importance. Here, we describe the present knowledge of the ICln interactome. ICln is a protein, we cloned and whose function was reported to be as divers as (i) ion permeation, (ii) cytoskeletal organization, and (iii) RNA processing. The role of ICln in these different functional modules can be described best as being a 'connector hub' with 'date hub' function.
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Affiliation(s)
- J Fürst
- Department of Physiology and Medical Physics, Innsbruck Medical University, Innsbruck, Austria
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Fürst J, Schedlbauer A, Gandini R, Garavaglia ML, Saino S, Gschwentner M, Sarg B, Lindner H, Jakab M, Ritter M, Bazzini C, Botta G, Meyer G, Kontaxis G, Tilly BC, Konrat R, Paulmichl M. ICln159 folds into a pleckstrin homology domain-like structure. Interaction with kinases and the splicing factor LSm4. J Biol Chem 2005; 280:31276-82. [PMID: 15905169 DOI: 10.1074/jbc.m500541200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ICln is a multifunctional protein involved in regulatory mechanisms as different as membrane ion transport and RNA splicing. The protein is water-soluble, and during regulatory volume decrease after cell swelling, it is able to migrate from the cytosol to the cell membrane. Purified, water-soluble ICln is able to insert into lipid bilayers to form ion channels. Here, we show that ICln159, a truncated ICln mutant, which is also able to form ion channels in lipid bilayers, belongs to the pleckstrin homology (PH) domain superfold family of proteins. The ICln PH domain shows unusual properties as it lacks the electrostatic surface polarization seen in classical PH domains. However, similar to many classical PH domain-containing proteins, ICln interacts with protein kinase C, and in addition, interacts with cAMP-dependent protein kinase and cGMP-dependent protein kinase type II but not cGMP-dependent protein kinase type Ibeta. A major phosphorylation site for all three kinases is Ser-45 within the ICln PH domain. Furthermore, ICln159 interacts with LSm4, a protein involved in splicing and mRNA degradation, suggesting that the ICln159 PH domain may serve as a protein-protein interaction platform.
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Affiliation(s)
- Johannes Fürst
- Department of Physiology and Medical Physics, Innsbruck Medical University, Fritz-Pregl Strasse 3, A-6020 Innsbruck, Austria
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7
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Ritter M, Ravasio A, Jakab M, Chwatal S, Fürst J, Laich A, Gschwentner M, Signorelli S, Burtscher C, Eichmüller S, Paulmichl M. Cell swelling stimulates cytosol to membrane transposition of ICln. J Biol Chem 2003; 278:50163-74. [PMID: 12970357 DOI: 10.1074/jbc.m300374200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ICln is a multifunctional protein that is essential for cell volume regulation. It can be found in the cytosol and is associated with the cell membrane. Besides its role in the splicing process, ICln is critically involved in the generation of ion currents activated during regulatory volume decrease after cell swelling (RVDC). If reconstituted in artificial bilayers, ICln can form ion channels with biophysical properties related to RVDC. We investigated (i) the cytosol versus cell membrane distribution of ICln in rat kidney tubules, NIH 3T3 fibroblasts, Madin-Darby canine kidney (MDCK) cells, and LLC-PK1 epithelial cells, (ii) fluorescence resonance energy transfer (FRET) in living fibroblasts between fluorescently tagged ICln and fluorochromes in the cell membrane, and (iii) possible functional consequences of an enhanced ICln presence at the cell membrane. We demonstrate that ICln distribution in rat kidneys depends on the parenchymal localization and functional state of the tubules and that cell swelling causes ICln redistribution from the cytosol to the cell membrane in NIH 3T3 fibroblasts and LLC-PK1 cells. The addition of purified ICln protein to the extracellular solution or overexpression of farnesylated ICln leads to an increased anion permeability in NIH 3T3 fibroblasts. The swelling-induced redistribution of ICln correlates to altered kinetics of RVDC in NIH 3T3 fibroblasts, LLC-PK1 cells, and MDCK cells. In these cells, RVDC develops more rapidly, and in MDCK cells the rate of swelling-induced depolarization is accelerated if cells are swollen for a second time. This coincides with an enhanced ICln association with the cell membrane.
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Affiliation(s)
- Markus Ritter
- Department of Physiology, University of Innsbruck, Fritz-Pregl-Strasse 3, A-6020 Innsbruck, Austria.
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Abstract
We demonstrated previously that expression of rat pICln in Escherichia coli conferred a strong resistance to hypotonic stress. To define the intramolecular functional domain responsible for the resistance, molecular dissection of pICln was performed and the obtained peptides were expressed in E. coli. The cells expressing the peptides were exposed to a hypotonic solution, and their 'survival rates' were observed. The cells expressing only the peptides including the second acidic domain of pICln exhibited significantly higher 'survival rates' after hypotonic stress. The functional domain against hypotonicity was finally narrowed down to a peptide consisting of a 46-amino acid residue, P107-152. We conclude that the expression of P107-152 in E. coli cells could enhance their resistance to a hypotonic environment.
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Affiliation(s)
- G Z Tao
- Department-2 of Biochemistry, School of Medicine, Akita University, Hondo 1-1-1, Akita, 010-8543, Japan.
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9
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Abstract
The actin cytoskeleton mediates a variety of essential biological functions in cells, including division, shape changes, and movement. A number of studies have suggested that the abundant submembranous actin cytoskeleton present in the cortex of many cell types is involved in the regulation of cell volume. This relationship is supported by numerous works which document the changes in the structural organization of the actin cytoskeleton which accompany cell volume changes and the F-actin-dependence of the regulatory volume responses. In addition, other studies demonstrate structural and functional relationships between the actin cytoskeleton and the membrane transporters known to be involved in cell volume homeostasis. This review provides a summary of the current level of knowledge in this area and discusses the mechanisms which may underlie the linkage between the actin cytoskeleton and cell volume regulation.
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Affiliation(s)
- J H Henson
- Department of Biology, Dickinson College, Carlisle, Pennsylvania 17013, USA.
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10
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Weber W. Ion currents of Xenopus laevis oocytes: state of the art. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1421:213-33. [PMID: 10518693 DOI: 10.1016/s0005-2736(99)00135-2] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- W Weber
- Laboratory of Physiology, K.U. Leuven, Campus Gasthuisberg, B-3000, Leuven, Belgium.
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Li C, Breton S, Morrison R, Cannon CL, Emma F, Sanchez-Olea R, Bear C, Strange K. Recombinant pICln forms highly cation-selective channels when reconstituted into artificial and biological membranes. J Gen Physiol 1998; 112:727-36. [PMID: 9834142 PMCID: PMC2229450 DOI: 10.1085/jgp.112.6.727] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/1998] [Accepted: 09/21/1998] [Indexed: 11/20/2022] Open
Abstract
pICln has been proposed to be the swelling-activated anion channel responsible for ICl, swell, or a channel regulator. We tested the anion channel hypothesis by reconstituting recombinant pICln into artificial and biological membranes. Single channels were observed when pICln was reconstituted into planar lipid bilayers. In the presence of symmetrical 300 mM KCl, the channels had a high open probability and a slope conductance of 48 pS, and were outwardly rectifying. Reduction of trans KCl to 50 mM shifted the reversal potential by -31.2 +/- 0.06 mV, demonstrating that the channel is at least seven times more selective for cations than for anions. Consistent with this finding, channel conductance was unaffected by substitution of Cl- with glutamate, but was undetectable when K+ was replaced by N-methyl-D-glucamine. Reconstitution of pICln into liposomes increased 86Rb+ uptake by three- to fourfold, but had no effect on 36Cl- uptake. Phosphorylation of pICln with casein kinase II or mutation of G54, G56, and G58 to alanine decreased channel open probability and 86Rb+ uptake. When added to the external medium bathing Sf9 cells, pICln inserted into the plasma membrane and increased cell cation permeability. Taken together, these observations demonstrate that channel activity is due to pICln and not minor contaminant proteins. However, these findings do not support the hypothesis that pICln is the anion-selective ICl, swell channel. The observed cation channel activity may reflect an as yet to be defined physiological function of pICln, or may be a consequence of in vitro reconstitution of purified, recombinant protein.
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Affiliation(s)
- C Li
- Division of Cell Biology, Research Institute, Hospital for Sick Children and Physiology Department, University of Toronto, Toronto, Ontario, Canada M5G 1X8
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