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Biochemical and subcellular characterization of a squid hnRNPA/B-like protein 2 in osmotic stress activated cells reflects molecular properties conserved in this protein family. Mol Biol Rep 2022; 49:4257-4268. [PMID: 35192131 DOI: 10.1007/s11033-022-07260-0] [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: 08/21/2021] [Accepted: 02/10/2022] [Indexed: 10/19/2022]
Abstract
BACKGROUND We have identified endogenous p65 to be an SDS-stable dimer protein composed of ~ 37 kDa hnRNPA/B-like subunits. We have investigated molecular properties involved in the stability of dimeric form, and their regulation in the transition between monomeric and dimeric forms of hnRNPA/B-like protein 2. We also investigated a cellular property conserved between squid hnRNPA/B-like protein 2 and human hnRNPA1 protein in a neuronal context. METHODS AND RESULTS Here we show biochemical properties of a recombinant hnRNPA/B-like protein 2 (rP2) in vitro experiments, as one of p65 subunit. We found that interaction between rP2 and RNA molecules interfered with the dynamics of rP2 dimers formation, involved in disulfide bonds and/or postranslational alterations in distinct stage of SDS-stable dimers formation. In addition, we have performed immunofluorescence in SH-SY5Y cells and observed that the pEGFP-P2 fusion protein was expressed in the nucleus, similar to what is observed for human hnRNPA1 protein. CONCLUSION Our results reinforce the idea that p65 is an SDS-stable dimer. Thus, a deeper understanding between monomeric and dimeric transition dynamic is critical into evolution of several neurodegenerative disease.
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Gagné M, Deshaies JE, Sidibé H, Benchaar Y, Arbour D, Dubinski A, Litt G, Peyrard S, Robitaille R, Sephton CF, Vande Velde C. hnRNP A1B, a Splice Variant of HNRNPA1, Is Spatially and Temporally Regulated. Front Neurosci 2021; 15:724307. [PMID: 34630013 PMCID: PMC8498194 DOI: 10.3389/fnins.2021.724307] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 08/30/2021] [Indexed: 11/28/2022] Open
Abstract
RNA binding proteins (RBPs) play a key role in cellular growth, homoeostasis and survival and are tightly regulated. A deep understanding of their spatiotemporal regulation is needed to understand their contribution to physiology and pathology. Here, we have characterized the spatiotemporal expression pattern of hnRNP A1 and its splice variant hnRNP A1B in mice. We have found that hnRNP A1B expression is more restricted to the CNS compared to hnRNP A1, and that it can form an SDS-resistant dimer in the CNS. Also, hnRNP A1B expression becomes progressively restricted to motor neurons in the ventral horn of the spinal cord, compared to hnRNP A1 which is more broadly expressed. We also demonstrate that hnRNP A1B is present in neuronal processes, while hnRNP A1 is absent. This finding supports a hypothesis that hnRNP A1B may have a cytosolic function in neurons that is not shared with hnRNP A1. Our results demonstrate that both isoforms are differentially expressed across tissues and have distinct localization profiles, suggesting that the two isoforms may have specific subcellular functions that can uniquely contribute to disease progression.
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Affiliation(s)
- Myriam Gagné
- Department of Biochemistry, Université de Montréal, Montréal, QC, Canada.,Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
| | - Jade-Emmanuelle Deshaies
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
| | - Hadjara Sidibé
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.,Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Yousri Benchaar
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, QC, Canada
| | - Danielle Arbour
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Alicia Dubinski
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.,Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Gurleen Litt
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
| | - Sarah Peyrard
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
| | - Richard Robitaille
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Chantelle F Sephton
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, QC, Canada
| | - Christine Vande Velde
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.,Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
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Lopes GS, Brusco J, Rosa JC, Larson RE, Lico DTP. Selectively RNA interaction by a hnRNPA/B-like protein at presynaptic terminal of squid neuron. INVERTEBRATE NEUROSCIENCE 2020; 20:14. [PMID: 32840710 DOI: 10.1007/s10158-020-00248-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 08/12/2020] [Indexed: 12/17/2022]
Abstract
In previous works, we identified a RNA-binding protein in presynaptic terminal of squid neurons, which is likely involved in local mRNA processing. Evidences indicate this strongly basic protein, called p65, is an SDS-stable dimer protein composed of ~ 37 kDa hnRNPA/B-like subunits. The function of p65 in presynaptic regions is not well understood. In this work, we showed p65 and its subunit p37 are concentrated in RNA-enriched regions in synaptosomes. We performed in vitro binding studies with a recombinant protein and showed its propensity to selectively bind actin mRNA at the squid presynaptic terminal. Biochemical analysis using lysed synaptosomes suggested RNA integrity may affect p65 and p37 functions. Mass spectrometry analysis of oligo(dT) pull down indicated squid hnRNPA1, hnRNPA1-like 2, hnRNPA3 and ELAV-like proteins as candidates to interact with p65 and p37 forming a ribonucleoprotein complex, suggesting a role of squid hnRNPA/B-like proteins in site-specific RNA processing.
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Affiliation(s)
- Gabriel S Lopes
- Department of Cellular and Molecular Biology, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Janaina Brusco
- Department of Cellular and Physiological Sciences and Brain Research Centre, University of British Columbia, Vancouver, BC, V6T 2B5, Canada
| | - José C Rosa
- Department of Cellular and Molecular Biology, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Roy E Larson
- Department of Cellular and Molecular Biology, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Diego T P Lico
- Department of Cellular and Molecular Biology, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil.
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A phylogenetically conserved hnRNP type A/B protein from squid brain. Neurosci Lett 2019; 696:219-224. [PMID: 30610890 DOI: 10.1016/j.neulet.2019.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 12/13/2018] [Accepted: 01/02/2019] [Indexed: 11/23/2022]
Abstract
Eukaryotic mRNA precursors are co-transcriptionally assembled into ribonucleoprotein complexes. Heterogeneous nuclear ribonucleoprotein (hnRNP) complexes are involved in mRNA translocation, stability, subcellular localization and regulation of mRNA translation. About 20 major classes of hnRNPs have been identified in mammals. In a previous work, we characterized a novel, strongly-basic, RNA-binding protein (p65) in presynaptic terminals of squid neurons presenting homology with human hnRNPA/B type proteins, likely involved in local mRNA processing. We have identified and sequenced two hnRNPA/B-like proteins associated with tissue purified squid p65: Protein 1 (36.3 kDa, IP 7.1) and Protein 2 (37.6 kDa, IP 8.9). In the present work we generated an in silico, tridimensional, structural model of squid hnRNPA/B-like Protein 2, which showed highly conserved secondary and tertiary structure of RNA recognition motifs with human hnRNPA1 protein, as well as illustrated the potential for squid Protein 2 stable homodimerization. This was supported by biophysical measurements of bacterially expressed, recombinant protein. In addition, we induced expression of squid hnRNPA/B-like Protein 2 in human neuroblastoma cells (SH-SY5Y) and observed an exclusively nuclear localization, which depended on an intact C-terminal amino acid sequence and which relocated to cytoplasm particles containing PABP when the cells were challenged with sorbitol, suggesting an involvement with stress granule function.
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