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Lee WY, Goh G, Chia J, Boey A, Gunko NV, Bard F. The Ubiquitin Ligase CBLC Maintains the Network Organization of the Golgi Apparatus. PLoS One 2015; 10:e0138789. [PMID: 26393512 PMCID: PMC4579092 DOI: 10.1371/journal.pone.0138789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 09/03/2015] [Indexed: 11/21/2022] Open
Abstract
The Golgi apparatus plays a pivotal role in the sorting and post-translational modifications of secreted and membrane proteins. In mammalian cells, the Golgi is organized in stacks of cisternae linked together to form a network with a ribbon shape. Regulation of Golgi ribbon formation is poorly understood. Here we find in an image-based RNAi screen that depletion of the ubiquitin-ligase CBLC induces Golgi fragmentation. Depletions of the close homologues CBL and CBLB do not induce any visible defects. In CBLC-depleted cells, Golgi stacks appear relatively unperturbed at both the light and electron microscopy levels, suggesting that CBLC controls mostly network organization. CBLC partially localizes on Golgi membranes and this localization is enhanced after activation of the SRC kinase. Inhibition of SRC reverts CBLC depletion effects, suggesting interplay between the two. CBLC's regulation of Golgi network requires its ubiquitin ligase activity. However, SRC levels are not significantly affected by CBLC, and CBLC knockdown does not phenocopy SRC activation, suggesting that CBLC's action at the Golgi is not direct downregulation of SRC. Altogether, our results demonstrate a role of CBLC in regulating Golgi ribbon by antagonizing the SRC tyrosine kinase.
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Affiliation(s)
- Wan Yin Lee
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Germaine Goh
- Institute of Molecular and Cell Biology, Singapore, Singapore
| | - Joanne Chia
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Adrian Boey
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Institute of Medical Biology, Singapore, Singapore
- IMB-IMCB Joint Electron Microscopy Suite, Singapore, Singapore
| | - Natalia V. Gunko
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Institute of Medical Biology, Singapore, Singapore
- IMB-IMCB Joint Electron Microscopy Suite, Singapore, Singapore
| | - Frederic Bard
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
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Panni S, Salvioli S, Santonico E, Langone F, Storino F, Altilia S, Franceschi C, Cesareni G, Castagnoli L. The adapter protein CD2AP binds to p53 protein in the cytoplasm and can discriminate its polymorphic variants P72R. J Biochem 2014; 157:101-11. [PMID: 25261582 DOI: 10.1093/jb/mvu059] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Proline-rich motifs are widely distributed in eukaryotic proteomes and are usually involved in the assembly of functional complexes through interaction with specific binding modules. The tumour-suppressor p53 protein presents a proline-rich region that is crucial for regulating apoptosis by connecting the p53 with a complex protein network. In humans, a common polymorphism determines the identity of residue 72, either proline or arginine, and affects the features of the motifs present in the polyproline domain. The two isoforms have different biochemical properties and markedly influence cancer onset and progression. In this article, we analyse the binding of the p53 proline-rich region with a pool of selected polyproline binding domains (i.e. SH3 and WW), and we present the first demonstration that the purified SH3 domains of the CD2AP/Cin85 protein family are able to directly bind the p53 protein, and to discriminate between the two polymorphic variants P72R.
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Affiliation(s)
- Simona Panni
- Department DiBEST, University of Calabria, Rende, 87036, Italy; DIMES, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy; CIG, Interdepartmental Center "Luigi Galvani", University of Bologna, Bologna 40126, Italy; Department of Biology, University of Rome Tor Vergata, Rome 00100, Italy; and Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, 00100, Italy
| | - Stefano Salvioli
- Department DiBEST, University of Calabria, Rende, 87036, Italy; DIMES, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy; CIG, Interdepartmental Center "Luigi Galvani", University of Bologna, Bologna 40126, Italy; Department of Biology, University of Rome Tor Vergata, Rome 00100, Italy; and Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, 00100, Italy Department DiBEST, University of Calabria, Rende, 87036, Italy; DIMES, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy; CIG, Interdepartmental Center "Luigi Galvani", University of Bologna, Bologna 40126, Italy; Department of Biology, University of Rome Tor Vergata, Rome 00100, Italy; and Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, 00100, Italy
| | - Elena Santonico
- Department DiBEST, University of Calabria, Rende, 87036, Italy; DIMES, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy; CIG, Interdepartmental Center "Luigi Galvani", University of Bologna, Bologna 40126, Italy; Department of Biology, University of Rome Tor Vergata, Rome 00100, Italy; and Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, 00100, Italy
| | - Francesca Langone
- Department DiBEST, University of Calabria, Rende, 87036, Italy; DIMES, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy; CIG, Interdepartmental Center "Luigi Galvani", University of Bologna, Bologna 40126, Italy; Department of Biology, University of Rome Tor Vergata, Rome 00100, Italy; and Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, 00100, Italy
| | - Francesca Storino
- Department DiBEST, University of Calabria, Rende, 87036, Italy; DIMES, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy; CIG, Interdepartmental Center "Luigi Galvani", University of Bologna, Bologna 40126, Italy; Department of Biology, University of Rome Tor Vergata, Rome 00100, Italy; and Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, 00100, Italy
| | - Serena Altilia
- Department DiBEST, University of Calabria, Rende, 87036, Italy; DIMES, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy; CIG, Interdepartmental Center "Luigi Galvani", University of Bologna, Bologna 40126, Italy; Department of Biology, University of Rome Tor Vergata, Rome 00100, Italy; and Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, 00100, Italy Department DiBEST, University of Calabria, Rende, 87036, Italy; DIMES, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy; CIG, Interdepartmental Center "Luigi Galvani", University of Bologna, Bologna 40126, Italy; Department of Biology, University of Rome Tor Vergata, Rome 00100, Italy; and Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, 00100, Italy
| | - Claudio Franceschi
- Department DiBEST, University of Calabria, Rende, 87036, Italy; DIMES, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy; CIG, Interdepartmental Center "Luigi Galvani", University of Bologna, Bologna 40126, Italy; Department of Biology, University of Rome Tor Vergata, Rome 00100, Italy; and Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, 00100, Italy Department DiBEST, University of Calabria, Rende, 87036, Italy; DIMES, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy; CIG, Interdepartmental Center "Luigi Galvani", University of Bologna, Bologna 40126, Italy; Department of Biology, University of Rome Tor Vergata, Rome 00100, Italy; and Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, 00100, Italy
| | - Gianni Cesareni
- Department DiBEST, University of Calabria, Rende, 87036, Italy; DIMES, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy; CIG, Interdepartmental Center "Luigi Galvani", University of Bologna, Bologna 40126, Italy; Department of Biology, University of Rome Tor Vergata, Rome 00100, Italy; and Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, 00100, Italy Department DiBEST, University of Calabria, Rende, 87036, Italy; DIMES, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy; CIG, Interdepartmental Center "Luigi Galvani", University of Bologna, Bologna 40126, Italy; Department of Biology, University of Rome Tor Vergata, Rome 00100, Italy; and Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, 00100, Italy
| | - Luisa Castagnoli
- Department DiBEST, University of Calabria, Rende, 87036, Italy; DIMES, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy; CIG, Interdepartmental Center "Luigi Galvani", University of Bologna, Bologna 40126, Italy; Department of Biology, University of Rome Tor Vergata, Rome 00100, Italy; and Istituto Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, 00100, Italy
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Shelkovnikova TA, Robinson HK, Southcombe JA, Ninkina N, Buchman VL. Multistep process of FUS aggregation in the cell cytoplasm involves RNA-dependent and RNA-independent mechanisms. Hum Mol Genet 2014; 23:5211-26. [PMID: 24842888 PMCID: PMC4159159 DOI: 10.1093/hmg/ddu243] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Fused in sarcoma (FUS) is an RNA-binding protein involved in pathogenesis of several neurodegenerative diseases. Aggregation of mislocalized FUS into non-amyloid inclusions is believed to be pivotal in the development of cell dysfunction, but the mechanism of their formation is unclear. Using transient expression of a panel of deletion and chimeric FUS variants in various cultured cells, we demonstrated that FUS accumulating in the cytoplasm nucleates a novel type of RNA granules, FUS granules (FGs), that are structurally similar but not identical to physiological RNA transport granules. Formation of FGs requires FUS N-terminal prion-like domain and the ability to bind specific RNAs. Clustering of FGs coupled with further recruitment of RNA and proteins produce larger structures, FUS aggregates (FAs), that resemble but are clearly distinct from stress granules. In conditions of attenuated transcription, FAs lose RNA and dissociate into RNA-free FUS complexes that become precursors of large aggresome-like structures. We propose a model of multistep FUS aggregation involving RNA-dependent and RNA-independent stages. This model can be extrapolated to formation of pathological inclusions in human FUSopathies.
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Affiliation(s)
- Tatyana A Shelkovnikova
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK, Institute of Physiologically Active Compounds Russian Academy of Sciences, 1 Severniy proezd, Chernogolovka 142432, Moscow Region, Russian Federation and
| | - Hannah K Robinson
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Joshua A Southcombe
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Natalia Ninkina
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK, Institute of General Pathology and Pathophysiology of Russian Academy of Medical Science, 8 Baltijskaya str, Moscow 125315, Russian Federation
| | - Vladimir L Buchman
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK,
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