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Sugio S, Tohyama K, Oku S, Fujiyoshi K, Yoshimura T, Hikishima K, Yano R, Fukuda T, Nakamura M, Okano H, Watanabe M, Fukata M, Ikenaka K, Tanaka KF. Astrocyte-mediated infantile-onset leukoencephalopathy mouse model. Glia 2016; 65:150-168. [DOI: 10.1002/glia.23084] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 09/22/2016] [Accepted: 09/29/2016] [Indexed: 01/09/2023]
Affiliation(s)
- Shouta Sugio
- Division of Neurobiology and Bioinformatics; National Institute for Physiological Sciences; Okazaki 444-8787 Japan
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki 444-8787 Japan
| | - Koujiro Tohyama
- Department of Physiology School of Dentistry, The Center of EM and Bio-Imaging Research, Nano-Neuroanatomy; Iwate Medical University; Morioka 020-8505 Japan
| | - Shinichiro Oku
- Division of Membrane Physiology, National Institute for Physiological Sciences; Okazaki 444-8787 Japan
| | - Kanehiro Fujiyoshi
- Department of Orthopedic Surgery; Keio University School of Medicine; Tokyo 160-8582 Japan
- Department of Orthopedic Surgery; National Hospital Organization, Murayama Medical Center; Tokyo 208-0011 Japan
| | - Takeshi Yoshimura
- Division of Neurobiology and Bioinformatics; National Institute for Physiological Sciences; Okazaki 444-8787 Japan
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki 444-8787 Japan
| | - Keigo Hikishima
- Department of Physiology; Keio University School of Medicine; Tokyo 160-8582 Japan
- Central Institute for Experimental Animals; Kawasaki 210-0821 Japan
| | - Ryutaro Yano
- Department of Physiology; Keio University School of Medicine; Tokyo 160-8582 Japan
| | - Takahiro Fukuda
- Division of Neuropathology, Department of Pathology; The Jikei University School of Medicine; Tokyo 105-8461 Japan
| | - Masaya Nakamura
- Department of Orthopedic Surgery; Keio University School of Medicine; Tokyo 160-8582 Japan
| | - Hideyuki Okano
- Department of Physiology; Keio University School of Medicine; Tokyo 160-8582 Japan
| | - Masahiko Watanabe
- Department of Anatomy; Hokkaido University Graduate School of Medicine; Sapporo 060-8638 Japan
| | - Masaki Fukata
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki 444-8787 Japan
- Division of Membrane Physiology, National Institute for Physiological Sciences; Okazaki 444-8787 Japan
| | - Kazuhiro Ikenaka
- Division of Neurobiology and Bioinformatics; National Institute for Physiological Sciences; Okazaki 444-8787 Japan
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki 444-8787 Japan
| | - Kenji F. Tanaka
- Division of Neurobiology and Bioinformatics; National Institute for Physiological Sciences; Okazaki 444-8787 Japan
- Department of Neuropsychiatry; Keio University School of Medicine; Tokyo 160-8582 Japan
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Abdel-Salam GMH, Abdel-Hamid MS, Ismail SI, Hosny H, Omar T, Effat L, Aglan MS, Temtamy SA, Zaki MS. Megalencephalic leukoencephalopathy with cysts in twelve Egyptian patients: novel mutations in MLC1 and HEPACAM and a founder effect. Metab Brain Dis 2016; 31:1171-9. [PMID: 27389245 DOI: 10.1007/s11011-016-9861-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 06/19/2016] [Indexed: 11/25/2022]
Abstract
Two genes causing megalencephalic leukoencephalopathy with subcortical cysts (MLC) have been discovered so far. Here, we identified MLC1 and HEPACAM mutations in ten and two patients, respectively. The molecular results included an unreported inframe duplication mutation (c.929_930dupCTGCTG; p.L309dup) of MLC1 and a novel missense mutation c.293G>A (p.R98H) of HEPACAM. Further, the previously reported missense (c.278C>T; p.S93L) and the deletion/insertion (c.908_918delinsGCA; p.V303Gfs*96) were found in one and 8 patients (75 %), respectively. The 8 patients carrying the p.V303Gfs*96 shared a similar haplotype suggesting a founder effect. All mutations were in the homozygous state proving the autosomal recessive mode of inheritance. The core phenotype of macrocephaly, subcortical cysts and white matter appeared homogeneous although the patients differed in the onset, clinical course, disease severity and brain imaging findings. Our study expands the spectrum of mutations in MLC1 and HEPACAM and supports the genetic and clinical heterogeneity. Further, It confirms c.908_918delinsGCA (p.V303Gfs*96) as a founder mutation among Egyptian patients. This finding will contribute to provide targeted testing for this mutation in MLC patients in our population.
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Affiliation(s)
- Ghada M H Abdel-Salam
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Tahrir street, Dokki, Cairo, Egypt.
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt.
| | - Mohamed S Abdel-Hamid
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Samira I Ismail
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Tahrir street, Dokki, Cairo, Egypt
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
| | - Heba Hosny
- National Institute of Neuromotor system, Cairo, Egypt
| | - Tarek Omar
- Department of Pediatrics, Alexandria University, Alexandria, Egypt
| | - Laila Effat
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Mona S Aglan
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Tahrir street, Dokki, Cairo, Egypt
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
| | - Samia A Temtamy
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Tahrir street, Dokki, Cairo, Egypt
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Tahrir street, Dokki, Cairo, Egypt
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
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Barrallo-Gimeno A, Gradogna A, Zanardi I, Pusch M, Estévez R. Regulatory-auxiliary subunits of CLC chloride channel-transport proteins. J Physiol 2016; 593:4111-27. [PMID: 25762128 DOI: 10.1113/jp270057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/15/2015] [Indexed: 02/06/2023] Open
Abstract
The CLC family of chloride channels and transporters is composed by nine members, but only three of them, ClC-Ka/b, ClC-7 and ClC-2, have been found so far associated with auxiliary subunits. These CLC regulatory subunits are small proteins that present few common characteristics among them, both structurally and functionally, and their effects on the corresponding CLC protein are different. Barttin, a protein with two transmembrane domains, is essential for the membrane localization of ClC-K proteins and their activity in the kidney and inner ear. Ostm1 is a protein with a single transmembrane domain and a highly glycosylated N-terminus. Unlike the other two CLC auxiliary subunits, Ostm1 shows a reciprocal relationship with ClC-7 for their stability. The subcellular localization of Ostm1 depends on ClC-7 and not the other way around. ClC-2 is active on its own, but GlialCAM, a transmembrane cell adhesion molecule with two extracellular immunoglobulin (Ig)-like domains, regulates its subcellular localization and activity in glial cells. The common theme for these three proteins is their requirement for a proper homeostasis, since their malfunction leads to distinct diseases. We will review here their properties and their role in normal chloride physiology and the pathological consequences of their improper function.
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Affiliation(s)
- Alejandro Barrallo-Gimeno
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, University of Barcelona, Barcelona, Spain.,U-750, Centro de investigación en red de enfermedades raras (CIBERER), ISCIII, Barcelona, Spain
| | | | - Ilaria Zanardi
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genoa, Italy
| | - Michael Pusch
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genoa, Italy
| | - Raúl Estévez
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, University of Barcelona, Barcelona, Spain.,U-750, Centro de investigación en red de enfermedades raras (CIBERER), ISCIII, Barcelona, Spain
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Abstract
Background Jacobsen syndrome (JBS) is a contiguous gene deletion syndrome involving 11q terminal deletion. Interstitial deletions at distal 11q are rare and their contributions to the clinical phenotype of JBS are unknown. Case presentation We presented the chromosome microarray (CMA) data and the clinical features of two individuals carrying a non-overlapping de novo deletion each at the 11q23.3-q24.2 region in an effort to analyze the correlation between region of deletion at 11q and phenotype. Both deletions are likely pathogenic for patient’s condition. The deletion at 11q23.3q24.1 is associated with short stature, relative microcephaly, failure to thrive, hypotonia and sleeping disorder. The deletion at 11q24.2 involves HEPACAM and our patient’s clinical presentation (relative macrocephaly, abnormal MRI, mild developmental delay and seizure) is not inconsistent with Megalencephalic leukoencephalopathy with subcortical cysts 2B. Conclusions Our finds support the notion that more than one critical region at 11q23.3-qter are responsible for the variable clinical presentation of JBS, thus JBS is a true contiguous gene deletion syndrome where multiple loci contributed to the clinical characteristics of JBS. Small interstitial deletions at 11q23.3-q24.2 and their associated unique features also suggest emerging novel genomic disorders. Electronic supplementary material The online version of this article (doi:10.1186/s13039-016-0247-7) contains supplementary material, which is available to authorized users.
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Leukoencephalopathy associated with 11q24 deletion involving the gene encoding hepatic and glial cell adhesion molecule in two patients. Eur J Med Genet 2015; 58:492-6. [DOI: 10.1016/j.ejmg.2015.06.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 06/15/2015] [Indexed: 12/22/2022]
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Capdevila-Nortes X, Jeworutzki E, Elorza-Vidal X, Barrallo-Gimeno A, Pusch M, Estévez R. Structural determinants of interaction, trafficking and function in the ClC-2/MLC1 subunit GlialCAM involved in leukodystrophy. J Physiol 2015; 593:4165-80. [PMID: 26033718 DOI: 10.1113/jp270467] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 05/22/2015] [Indexed: 02/03/2023] Open
Abstract
KEY POINTS The extracellular domain of GlialCAM is necessary for its targeting to cell junctions, as well as for interactions with itself and MLC1 and ClC-2. The C-terminus of GlialCAM is not necessary for interaction but is required for targeting to cell junctions. The first three residues of the transmembrane segment of GlialCAM are required for GlialCAM-mediated ClC-2 activation. ABSTRACT Mutations in the genes encoding the astrocytic protein MLC1, the cell adhesion molecule GlialCAM or the Cl(-) channel ClC-2 underlie human leukodystrophies. GlialCAM binds to itself, to MLC1 and to ClC-2, and directs these proteins to cell-cell contacts. In addition, GlialCAM dramatically activates ClC-2 mediated currents. In the present study, we used mutagenesis studies combined with functional and biochemical analyses to determine which parts of GlialCAM are required to perform these cellular functions. We found that the extracellular domain of GlialCAM is necessary for cell junction targeting and for mediating interactions with itself or with MLC1 and ClC-2. The C-terminus is also necessary for proper targeting to cell-cell junctions but is not required for the biochemical interaction. Finally, we identified the first three amino acids of the transmembrane segment of GlialCAM as being essential for the activation of ClC-2 currents but not for targeting or biochemical interaction. Our results provide new mechanistic insights concerning the regulation of the cell biology and function of MLC1 and ClC-2 by GlialCAM.
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Affiliation(s)
- Xavier Capdevila-Nortes
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Barcelona, Spain
| | - Elena Jeworutzki
- Istituto di Biofisica, CNR, Genoa, Italy.,Present address IfGH-Myocellular Electrophysiology, Department of Cardiovascular Medicine, University Hospital of Münster, Münster, Germany
| | - Xabier Elorza-Vidal
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Barcelona, Spain.,U-750, Centro de investigación en red de enfermedades raras (CIBERER), ISCIII, Barcelona, Spain
| | - Alejandro Barrallo-Gimeno
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Barcelona, Spain
| | | | - Raúl Estévez
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Barcelona, Spain.,U-750, Centro de investigación en red de enfermedades raras (CIBERER), ISCIII, Barcelona, Spain
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Brignone MS, Lanciotti A, Camerini S, De Nuccio C, Petrucci TC, Visentin S, Ambrosini E. MLC1 protein: a likely link between leukodystrophies and brain channelopathies. Front Cell Neurosci 2015; 9:66. [PMID: 25883547 PMCID: PMC4381631 DOI: 10.3389/fncel.2015.00106] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/09/2015] [Indexed: 01/12/2023] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLCs) disease is a rare inherited, autosomal recessive form of childhood-onset spongiform leukodystrophy characterized by macrocephaly, deterioration of motor functions, epileptic seizures and mental decline. Brain edema, subcortical fluid cysts, myelin and astrocyte vacuolation are the histopathological hallmarks of MLC. Mutations in either the MLC1 gene (>75% of patients) or the GlialCAM gene (<20% of patients) are responsible for the disease. Recently, the GlialCAM adhesion protein was found essential for the membrane expression and function of the chloride channel ClC-2 indicating MLC disease caused by mutation in GlialCAM as the first channelopathy among leukodystrophies. On the contrary, the function of MLC1 protein, which binds GlialCAM, its functional relationship with ClC-2 and the molecular mechanisms underlying MLC1 mutation-induced functional defects are not fully understood yet. The human MLC1 gene encodes a 377-amino acid membrane protein with eight predicted transmembrane domains which shows very low homology with voltage-dependent potassium (K+) channel subunits. The high expression of MLC1 in brain astrocytes contacting blood vessels and meninges and brain alterations observed in MLC patients have led to hypothesize a role for MLC1 in the regulation of ion and water homeostasis. Recent studies have shown that MLC1 establishes structural and/or functional interactions with several ion/water channels and transporters and ion channel accessory proteins, and that these interactions are affected by MLC1 mutations causing MLC. Here, we review data on MLC1 functional properties obtained in in vitro and in vivo models and discuss evidence linking the effects of MLC1 mutations to brain channelopathies.
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Affiliation(s)
- Maria S Brignone
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Angela Lanciotti
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Serena Camerini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Chiara De Nuccio
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Tamara C Petrucci
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Sergio Visentin
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Elena Ambrosini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
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Abstract
Group I metabotropic glutamate (mGlu) receptors regulate hippocampal CA1 pyramidal neuron excitability via Ca(2+) wave-dependent activation of small-conductance Ca(2+)-activated K(+) (SK) channels. Here, we show that mGlu5 receptors and SK2 channels coassemble in heterologous coexpression systems and in rat brain. Further, in cotransfected cells or rat primary hippocampal neurons, mGlu5 receptor stimulation activated apamin-sensitive SK2-mediated K(+) currents. In addition, coexpression of mGlu5 receptors and SK2 channels promoted plasma membrane targeting of both proteins and correlated with increased mGlu5 receptor function that was unexpectedly blocked by apamin. These results demonstrate a reciprocal functional interaction between mGlu5 receptors and SK2 channels that reflects their molecular coassembly.
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Dubey M, Bugiani M, Ridder MC, Postma NL, Brouwers E, Polder E, Jacobs JG, Baayen JC, Klooster J, Kamermans M, Aardse R, de Kock CPJ, Dekker MP, van Weering JRT, Heine VM, Abbink TEM, Scheper GC, Boor I, Lodder JC, Mansvelder HD, van der Knaap MS. Mice with megalencephalic leukoencephalopathy with cysts: A developmental angle. Ann Neurol 2014; 77:114-31. [DOI: 10.1002/ana.24307] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 10/27/2014] [Accepted: 11/02/2014] [Indexed: 11/11/2022]
Affiliation(s)
- Mohit Dubey
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Marianna Bugiani
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Pathology; VU University Medical Center
| | - Margreet C. Ridder
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Nienke L. Postma
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Eelke Brouwers
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Emiel Polder
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - J. Gerbren Jacobs
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
| | | | - Jan Klooster
- Department of Retinal Signal Processing; Netherlands Institute for Neuroscience-KNAW; Amsterdam Netherlands
| | - Maarten Kamermans
- Department of Retinal Signal Processing; Netherlands Institute for Neuroscience-KNAW; Amsterdam Netherlands
| | - Romy Aardse
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Christiaan P. J. de Kock
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Marien P. Dekker
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
| | - Jan R. T. van Weering
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
| | - Vivi M. Heine
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
| | - Truus E. M. Abbink
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Gert C. Scheper
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Ilja Boor
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Johannes C. Lodder
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Huibert D. Mansvelder
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Marjo S. van der Knaap
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
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Inborn errors of metabolism: combining clinical and radiologic clues to solve the mystery. AJR Am J Roentgenol 2014; 203:W315-27. [PMID: 25148190 DOI: 10.2214/ajr.13.11154] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Inborn errors of metabolism in children can be challenging to interpret because of the similarity of their appearances on imaging. There are important clues to the diagnosis based on clinical history, head circumference (e.g., macrocephaly), geographic distribution of lesions (e.g., subcortical vs deep white matter or frontal vs parietooccipital), and other imaging features (e.g., contrast enhancement, calcification, cysts, and cortical dysplasia). CONCLUSION In this article, we present an algorithm-based approach to diagnosing pediatric metabolic disease with a discussion of key imaging features.
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Arnedo T, López-Hernández T, Jeworutzki E, Capdevila-Nortes X, Sirisi S, Pusch M, Estévez R. Functional Analyses of Mutations inHEPACAMCausing Megalencephalic Leukoencephalopathy. Hum Mutat 2014; 35:1175-8. [DOI: 10.1002/humu.22622] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 07/03/2014] [Indexed: 01/10/2023]
Affiliation(s)
- Tanit Arnedo
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II; University of Barcelona; Barcelona Spain
- U-750; Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII; Barcelona Spain
| | - Tania López-Hernández
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II; University of Barcelona; Barcelona Spain
| | - Elena Jeworutzki
- Istituto di Biofisica; Consiglio Nazionale delle Ricerche; Genoa 16149 Italy
| | - Xavier Capdevila-Nortes
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II; University of Barcelona; Barcelona Spain
| | - Sònia Sirisi
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II; University of Barcelona; Barcelona Spain
| | - Michael Pusch
- Istituto di Biofisica; Consiglio Nazionale delle Ricerche; Genoa 16149 Italy
| | - Raúl Estévez
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II; University of Barcelona; Barcelona Spain
- U-750; Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII; Barcelona Spain
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62
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Sirisi S, Folgueira M, López-Hernández T, Minieri L, Pérez-Rius C, Gaitán-Peñas H, Zang J, Martínez A, Capdevila-Nortes X, De La Villa P, Roy U, Alia A, Neuhauss S, Ferroni S, Nunes V, Estévez R, Barrallo-Gimeno A. Megalencephalic leukoencephalopathy with subcortical cysts protein 1 regulates glial surface localization of GLIALCAM from fish to humans. Hum Mol Genet 2014; 23:5069-86. [DOI: 10.1093/hmg/ddu231] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Nunes RH, Pacheco FT, da Rocha AJ. Magnetic resonance imaging of anterior temporal lobe cysts in children: discriminating special imaging features in a particular group of diseases. Neuroradiology 2014; 56:569-77. [DOI: 10.1007/s00234-014-1356-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 03/19/2014] [Indexed: 11/29/2022]
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Disrupting MLC1 and GlialCAM and ClC-2 interactions in leukodystrophy entails glial chloride channel dysfunction. Nat Commun 2014; 5:3475. [PMID: 24647135 DOI: 10.1038/ncomms4475] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 02/18/2014] [Indexed: 11/08/2022] Open
Abstract
Defects in the astrocytic membrane protein MLC1, the adhesion molecule GlialCAM or the chloride channel ClC-2 underlie human leukoencephalopathies. Whereas GlialCAM binds ClC-2 and MLC1, and modifies ClC-2 currents in vitro, no functional connections between MLC1 and ClC-2 are known. Here we investigate this by generating loss-of-function Glialcam and Mlc1 mouse models manifesting myelin vacuolization. We find that ClC-2 is unnecessary for MLC1 and GlialCAM localization in brain, whereas GlialCAM is important for targeting MLC1 and ClC-2 to specialized glial domains in vivo and for modifying ClC-2's biophysical properties specifically in oligodendrocytes (OLs), the cells chiefly affected by vacuolization. Unexpectedly, MLC1 is crucial for proper localization of GlialCAM and ClC-2, and for changing ClC-2 currents. Our data unmask an unforeseen functional relationship between MLC1 and ClC-2 in vivo, which is probably mediated by GlialCAM, and suggest that ClC-2 participates in the pathogenesis of megalencephalic leukoencephalopathy with subcortical cysts.
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Marchese M, Conti V, Valvo G, Moro F, Muratori F, Tancredi R, Santorelli FM, Guerrini R, Sicca F. Autism-epilepsy phenotype with macrocephaly suggests PTEN, but not GLIALCAM, genetic screening. BMC MEDICAL GENETICS 2014; 15:26. [PMID: 24580998 PMCID: PMC3941568 DOI: 10.1186/1471-2350-15-26] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 02/21/2014] [Indexed: 01/27/2023]
Abstract
BACKGROUND With a complex and extremely high clinical and genetic heterogeneity, autism spectrum disorders (ASD) are better dissected if one takes into account specific endophenotypes. Comorbidity of ASD with epilepsy (or paroxysmal EEG) has long been described and seems to have strong genetic background. Macrocephaly also represents a well-known endophenotype in subgroups of ASD individuals, which suggests pathogenic mechanisms accelerating brain growth in early development and predisposing to the disorder. We attempted to estimate the association of gene variants with neurodevelopmental disorders in patients with autism-epilepsy phenotype (AEP) and cranial overgrowth, analyzing two genes previously reported to be associated with autism and macrocephaly. METHODS We analyzed the coding sequences and exon-intron boundaries of GLIALCAM, encoding an IgG-like cell adhesion protein, in 81 individuals with Autism Spectrum Disorders, either with or without comorbid epilepsy, paroxysmal EEG and/or macrocephaly, and the PTEN gene in the subsample with macrocephaly. RESULTS Among 81 individuals with ASD, 31 had concurrent macrocephaly. Head circumference, moreover, was over the 99.7th percentile ("extreme" macrocephaly) in 6/31 (19%) patients. Whilst we detected in GLIALCAM several single nucleotide variants without clear pathogenic effects, we found a novel PTEN heterozygous frameshift mutation in one case with "extreme" macrocephaly, autism, intellectual disability and seizures. CONCLUSIONS We did not find a clear association between GLIALCAM mutations and AEP-macrocephaly comorbidity. The identification of a novel frameshift variant of PTEN in a patient with "extreme" macrocephaly, autism, intellectual disability and seizures, confirms this gene as a major candidate in the ASD-macrocephaly endophenotype. The concurrence of epilepsy in the same patient also suggests that PTEN, and the downstream signaling pathway, might deserve to be investigated in autism-epilepsy comorbidity. Working on clinical endophenotypes might be of help to address genetic studies and establish actual causative correlations in autism-epilepsy.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Federico Sicca
- Clinical Neurophysiology Laboratory, IRCCS Stella Maris Foundation, Viale del Tirreno 331, Pisa, Calambrone 56128, Italy.
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Barrallo-Gimeno A, Estévez R. GlialCAM, a glial cell adhesion molecule implicated in neurological disease. ADVANCES IN NEUROBIOLOGY 2014; 8:47-59. [PMID: 25300132 DOI: 10.1007/978-1-4614-8090-7_3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
GlialCAM (also named HepaCAM) is a cell adhesion molecule expressed mainly in glial cells from the central nervous system and the liver. GlialCAM plays different roles according to its cellular context. In epithelial cell lines, overexpression of GlialCAM increases cell adhesion and motility but also inhibits cell growth in tumor cell lines, leading to senescence. In glial cells, however, its function is quite different. GlialCAM acts a regulator of subcellular traffic of MLC1, a protein with unknown function involved in the pathogenesis of megalencephalic leukoencephalopathy with subcortical cysts (MLC), a rare neurological condition. Moreover, GlialCAM itself has been found to be responsible for some of the cases of this disease. Additionally, GlialCAM also works as an auxiliary subunit of the chloride channel ClC-2, regulating its targeting to cell-cell junctions and modifying its functional properties. In summary, GlialCAM has different functions not only related to its adhesive nature, and defects in these functions lead to neurological disease.
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67
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Expanding the spectrum of megalencephalic leukoencephalopathy with subcortical cysts in two patients with GLIALCAM mutations. Neurogenetics 2013; 15:41-8. [DOI: 10.1007/s10048-013-0381-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 10/09/2013] [Indexed: 10/26/2022]
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68
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Capdevila-Nortes X, López-Hernández T, Apaja PM, López de Heredia M, Sirisi S, Callejo G, Arnedo T, Nunes V, Lukacs GL, Gasull X, Estévez R. Insights into MLC pathogenesis: GlialCAM is an MLC1 chaperone required for proper activation of volume-regulated anion currents. Hum Mol Genet 2013; 22:4405-16. [DOI: 10.1093/hmg/ddt290] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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69
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Naidu S, Lin DDM. Advances in the diagnosis of leukoencephalopathies. ACTA ACUST UNITED AC 2013; 6:259-73. [PMID: 23480738 DOI: 10.1517/17530059.2012.665869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Introduction : Leukoencephalopathies (LEs) are a diverse group of diseases involving cerebral white matter. Some of the disorders may be infectious or immunologically mediated and, therefore, tend to be more amenable to treatment. Most of these disorders have a genetic basis, for which genetic counseling becomes important as currently very few of them have effective therapies. Areas covered : This review calls attention to the diagnostic dilemmas, highlights the diagnostic tests of choice for separating conditions with similar clinical, laboratory or neuroimaging findings, and describes several LEs that have been newly discovered within the last 20 years. Imaging of LEs has progressed rapidly since the introduction of magnetic resonance imaging (MRI) and spectroscopy (MRS), allowing recognition of new diseases, with and without identifiable corresponding biochemical or genetic defects. The distinguishing MRI and MRS features of LEs are described, as well as the resources available for biochemical, CSF and blood sample testing for diagnosis and differentiation from previously known LEs. Expert opinion : Although there is no treatment at present for many of the LEs, their detection as a cause of intellectual and motor disabilities, and as inherited disorders, makes it necessary to accurately categorize them. This knowledge will then allow further elucidation of the etiology, understanding the biological underpinnings, and eventually progress toward rational therapies.
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Affiliation(s)
- Sakkubai Naidu
- Johns Hopkins University School of Medicine, Hugo Moser Research Institute, Kennedy Krieger Institute , 707, N. Broadway, Baltimore, MD 21205 , USA +1 443 923 2778 ; +1 443 923 2779 ;
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van der Knaap MS, Boor I, Estévez R. Megalencephalic leukoencephalopathy with subcortical cysts: chronic white matter oedema due to a defect in brain ion and water homoeostasis. Lancet Neurol 2012; 11:973-85. [PMID: 23079554 DOI: 10.1016/s1474-4422(12)70192-8] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is characterised by chronic white matter oedema. The disease has an infantile onset and leads to slow neurological deterioration in most cases, but, surprisingly, some patients recover. The first disease gene, MLC1, identified in 2001, is mutated in 75% of patients. At that time, nothing was known about MLC1 protein function and the pathophysiology of MLC. More recently, HEPACAM (also called GLIALCAM) has been identified as a second disease gene. GlialCAM serves as an escort for MLC1 and the chloride channel CLC2. The defect in MLC1 has been shown to hamper the cell volume regulation of astrocytes. One of the most important consequences involves the potassium siphoning process, which is essential in brain ion and water homoeostasis. An understanding of the mechanisms of white matter oedema in MLC is emerging. Further insight into the specific function of MLC1 is necessary to find treatment targets.
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Affiliation(s)
- Marjo S van der Knaap
- Department of Pediatrics/Child Neurology, VU University Medical Centre, Amsterdam, Netherlands.
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71
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de Monasterio-Schrader P, Jahn O, Tenzer S, Wichert SP, Patzig J, Werner HB. Systematic approaches to central nervous system myelin. Cell Mol Life Sci 2012; 69:2879-94. [PMID: 22441408 PMCID: PMC11114939 DOI: 10.1007/s00018-012-0958-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 03/05/2012] [Indexed: 12/11/2022]
Abstract
Rapid signal propagation along vertebrate axons is facilitated by their insulation with myelin, a plasma membrane specialization of glial cells. The recent application of 'omics' approaches to the myelinating cells of the central nervous system, oligodendrocytes, revealed their mRNA signatures, enhanced our understanding of how myelination is regulated, and established that the protein composition of myelin is much more complex than previously thought. This review provides a meta-analysis of the > 1,200 proteins thus far identified by mass spectrometry in biochemically purified central nervous system myelin. Contaminating proteins are surprisingly infrequent according to bioinformatic prediction of subcellular localization and comparison with the transcriptional profile of oligodendrocytes. The integration of datasets also allowed the subcategorization of the myelin proteome into functional groups comprising genes that are coregulated during oligodendroglial differentiation. An unexpectedly large number of myelin-related genes cause-when mutated in humans-hereditary diseases affecting the physiology of the white matter. Systematic approaches to oligodendrocytes and myelin thus provide valuable resources for the molecular dissection of developmental myelination, glia-axonal interactions, leukodystrophies, and demyelinating diseases.
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Affiliation(s)
| | - Olaf Jahn
- Proteomics Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- DFG Research Center for Molecular Physiology of the Brain, Göttingen, Germany
| | - Stefan Tenzer
- Institute of Immunology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Sven P. Wichert
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Julia Patzig
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Hauke B. Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
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72
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Mancini C, Vaula G, Scalzitti L, Cavalieri S, Bertini E, Aiello C, Lucchini C, Gatti RA, Brussino A, Brusco A. Megalencephalic leukoencephalopathy with subcortical cysts type 1 (MLC1) due to a homozygous deep intronic splicing mutation (c.895-226T>G) abrogated in vitro using an antisense morpholino oligonucleotide. Neurogenetics 2012; 13:205-14. [PMID: 22552818 DOI: 10.1007/s10048-012-0331-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 04/16/2012] [Indexed: 11/24/2022]
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts is an autosomal recessive disease characterized by early onset macrocephaly; developmental delay; motor disability in the form of progressive spasticity and ataxia; seizures; cognitive decline; and characteristic magnetic resonance imaging findings. Mutations in two genes, MLC1 (22q13.33; 75 % of patients) or HEPACAM (11q24; 20 % of patients), are associated with the disease. We describe an adult MLC patient with moderate clinical symptoms. MLC1 cDNA analysis from lymphoblasts showed a strong transcript reduction and identified a 246-bp pseudoexon containing a premature stop codon between exons 10 and 11, due to a homozygous c.895-226 T>G deep-intronic mutation. This category of mutations is often overlooked, being outside of canonically sequenced genomic regions. The mutation c.895-226 T>G has a leaky effect on splicing leaving part of the full-length transcript. Its role on splicing was confirmed using a minigene assay and an antisense morpholinated oligonucleotide targeted to the aberrant splice site in vitro, which partially abrogated the mutation effect.
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Affiliation(s)
- Cecilia Mancini
- Department of Genetics, Biology and Biochemistry, University of Torino, via Santena, 19-10126 Torino, Italy
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73
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Jeworutzki E, López-Hernández T, Capdevila-Nortes X, Sirisi S, Bengtsson L, Montolio M, Zifarelli G, Arnedo T, Müller CS, Schulte U, Nunes V, Martínez A, Jentsch TJ, Gasull X, Pusch M, Estévez R. GlialCAM, a protein defective in a leukodystrophy, serves as a ClC-2 Cl(-) channel auxiliary subunit. Neuron 2012; 73:951-61. [PMID: 22405205 PMCID: PMC3334819 DOI: 10.1016/j.neuron.2011.12.039] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2011] [Indexed: 11/30/2022]
Abstract
Ion fluxes mediated by glial cells are required for several physiological processes such as fluid homeostasis or the maintenance of low extracellular potassium during high neuronal activity. In mice, the disruption of the Cl− channel ClC-2 causes fluid accumulation leading to myelin vacuolation. A similar vacuolation phenotype is detected in humans affected with megalencephalic leukoencephalopathy with subcortical cysts (MLC), a leukodystrophy which is caused by mutations in MLC1 or GLIALCAM. We here identify GlialCAM as a ClC-2 binding partner. GlialCAM and ClC-2 colocalize in Bergmann glia, in astrocyte-astrocyte junctions at astrocytic endfeet around blood vessels, and in myelinated fiber tracts. GlialCAM targets ClC-2 to cell junctions, increases ClC-2 mediated currents, and changes its functional properties. Disease-causing GLIALCAM mutations abolish the targeting of the channel to cell junctions. This work describes the first auxiliary subunit of ClC-2 and suggests that ClC-2 may play a role in the pathology of MLC disease. Video Abstract
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Affiliation(s)
- Elena Jeworutzki
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, 16149 Genoa, Italy
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74
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Xie H, Wang J, Dhaunchak AS, Shang J, Kou L, Guo M, Wu Y, Gu Q, Colman D, Wu X, Jiang Y. Functional studies of MLC1 mutations in Chinese patients with megalencephalic leukoencephalopathy with subcortical cysts. PLoS One 2012; 7:e33087. [PMID: 22416245 PMCID: PMC3293920 DOI: 10.1371/journal.pone.0033087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 02/07/2012] [Indexed: 01/06/2023] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC, MIM# 604004) is an autosomal recessive inherited disease mostly resulting from MLC1 mutations. In this study, we finished the functional analysis of MLC1 mutations identified recently in Chinese patients, including five newly described missense mutations (R22Q, A32V, G73E, A275T, Y278H), one known nonsense mutation (Y198X), and two known missense mutations (S69L, T118M). We found MLC1wt was localized to the cell periphery, whereas mutant R22Q, A32V, G73E, S69L and T118M were trapped in the lumen of endoplasmic reticulum (ER) when we transfected the wild-type and mutant MLC1 in U373MG cells. Compared to wild type, the mutant G73E, T118M, Y198X and A275T transcript decreased and all mutants except R22Q had lower protein expression in transfected U373MG cells. Therefore, we propose that all these eight MLC1 mutations had functional effect either on their protein/mRNA expression, or on their intracellular protein localization, or both.
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Affiliation(s)
- Han Xie
- Department of Pediatrics, Peking University First Hospital, Beijing, People's Republic of China
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, People's Republic of China
| | | | - Jing Shang
- Department of Pediatrics, Peking University First Hospital, Beijing, People's Republic of China
- Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China
| | - Liping Kou
- Department of Pediatrics, Peking University First Hospital, Beijing, People's Republic of China
- Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China
| | - Mangmang Guo
- Department of Pediatrics, Peking University First Hospital, Beijing, People's Republic of China
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, Beijing, People's Republic of China
| | - Qiang Gu
- Department of Pediatrics, Peking University First Hospital, Beijing, People's Republic of China
| | - David Colman
- Montreal Neurological Institute, Montreal, Quebec, Canada
| | - Xiru Wu
- Department of Pediatrics, Peking University First Hospital, Beijing, People's Republic of China
- * E-mail: (XW); (YJ)
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, People's Republic of China
- * E-mail: (XW); (YJ)
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Lanciotti A, Brignone MS, Molinari P, Visentin S, De Nuccio C, Macchia G, Aiello C, Bertini E, Aloisi F, Petrucci TC, Ambrosini E. Megalencephalic leukoencephalopathy with subcortical cysts protein 1 functionally cooperates with the TRPV4 cation channel to activate the response of astrocytes to osmotic stress: dysregulation by pathological mutations. Hum Mol Genet 2012; 21:2166-80. [PMID: 22328087 DOI: 10.1093/hmg/dds032] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC), a rare leukodystrophy characterized by macrocephaly, subcortical fluid cysts and myelin vacuolation, has been linked to mutations in the MLC1 gene. This gene encodes a membrane protein that is highly expressed in astrocytes. Based on MLC pathological features, it was proposed that astrocyte-mediated defects in ion and fluid homeostasis could account for the alterations observed in MLC-affected brains. However, the role of MLC1 and the effects of pathological mutations on astrocyte osmoregulatory functions have still to be demonstrated. Using human astrocytoma cells stably overexpressing wild-type MLC1 or three known MLC-associated pathological mutations, we investigated MLC1 involvement in astrocyte reaction to osmotic changes using biochemical, dynamic video imaging and immunofluorescence techniques. We have found that MLC1 overexpressed in astrocytoma cells is mainly localized in the plasma membrane, is part of the Na,K-ATPase-associated molecular complex that includes the potassium channel Kir4.1, syntrophin and aquaporin-4 and functionally interacts with the calcium permeable channel TRPV4 (transient receptor potential vanilloid-4 cation channel) which mediates swelling-induced cytosolic calcium increase and volume recovery in response to hyposmosis. Pathological MLC mutations cause changes in MLC1 expression and intracellular localization as well as in the astrocyte response to osmotic changes by altering MLC1 molecular interactions with the Na,K-ATPase molecular complex and abolishing the increase in calcium influx induced by hyposmosis and treatment with the TRPV4 agonist 4αPDD. These data demonstrate, for the first time, that MLC1 plays a role in astrocyte osmo-homeostasis and that defects in intracellular calcium dynamics may contribute to MLC pathogenesis.
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Affiliation(s)
- Angela Lanciotti
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità,Viale Regina Elena 299, Rome 00161, Italy
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Capdevila-Nortes X, López-Hernández T, Ciruela F, Estévez R. A modification of the split-tobacco etch virus method for monitoring interactions between membrane proteins in mammalian cells. Anal Biochem 2012; 423:109-18. [PMID: 22342621 DOI: 10.1016/j.ab.2012.01.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 01/18/2012] [Accepted: 01/23/2012] [Indexed: 01/02/2023]
Abstract
Despite progress in the development of methods to monitor protein interactions, studies of interactions between membrane proteins in mammalian cells remain challenging. Protein complementation assays (PCAs) are commonly used to study interactions between proteins due to their simplicity. They are based on interaction-mediated reconstitution of a reporter protein, which can be easily monitored. Recently, a protein complementation method named split-TEV (tobacco etch virus) has been developed and is based on the functional reconstitution of TEV protease and subsequent proteolytic-mediated activation of reporters. In this work, we have developed a modification of the split-TEV method to study the interactions between membrane proteins with increased specificity. This assay was validated by addressing the interactions between different membrane proteins, including G protein-coupled receptors (GPCRs) and ion channels. By comparing it with another PCA, we found that this new method showed a higher sensitivity.
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Affiliation(s)
- Xavier Capdevila-Nortes
- Sección de Fisiología, Departamento de Ciencias Fisiologicas II, Universidad de Barcelona, 08907 Barcelona, Spain
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