1
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Wales-McGrath B, Mercer H, Piontkivska H. Changes in ADAR RNA editing patterns in CMV and ZIKV congenital infections. BMC Genomics 2023; 24:685. [PMID: 37968596 PMCID: PMC10652522 DOI: 10.1186/s12864-023-09778-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 10/31/2023] [Indexed: 11/17/2023] Open
Abstract
BACKGROUND RNA editing is a process that increases transcriptome diversity, often through Adenosine Deaminases Acting on RNA (ADARs) that catalyze the deamination of adenosine to inosine. ADAR editing plays an important role in regulating brain function and immune activation, and is dynamically regulated during brain development. Additionally, the ADAR1 p150 isoform is induced by interferons in viral infection and plays a role in antiviral immune response. However, the question of how virus-induced ADAR expression affects host transcriptome editing remains largely unanswered. This question is particularly relevant in the context of congenital infections, given the dynamic regulation of ADAR editing during brain development, the importance of this editing for brain function, and subsequent neurological symptoms of such infections, including microcephaly, sensory issues, and other neurodevelopmental abnormalities. Here, we begin to address this question, examining ADAR expression in publicly available datasets of congenital infections of human cytomegalovirus (HCMV) microarray expression data, as well as mouse cytomegalovirus (MCMV) and mouse/ human induced pluripotent neuroprogenitor stem cell (hiNPC) Zika virus (ZIKV) RNA-seq data. RESULTS We found that in all three datasets, ADAR1 was overexpressed in infected samples compared to uninfected samples. In the RNA-seq datasets, editing rates were also analyzed. In all mouse infections cases, the number of editing sites was significantly increased in infected samples, albeit this was not the case for hiNPC ZIKV samples. Mouse ZIKV samples showed altered editing of well-established protein-recoding sites such as Gria3, Grik5, and Nova1, as well as editing sites that may impact miRNA binding. CONCLUSIONS Our findings provide evidence for changes in ADAR expression and subsequent dysregulation of ADAR editing of host transcriptomes in congenital infections. These changes in editing patterns of key neural genes have potential significance in the development of neurological symptoms, thus contributing to neurodevelopmental abnormalities. Further experiments should be performed to explore the full range of editing changes that occur in different congenital infections, and to confirm the specific functional consequences of these editing changes.
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Affiliation(s)
- Benjamin Wales-McGrath
- University of Pennsylvania, Perelman School of Medicine, Department of Genetics, Philadelphia, PA, USA
- Children's Hospital of Philadelphia, Division of Cancer Pathobiology, Philadelphia, PA, USA
| | - Heather Mercer
- Department of Biological and Environmental Sciences, University of Mount Union, Alliance, OH, USA
| | - Helen Piontkivska
- Department of Biological Sciences, Kent State University, Kent, OH, USA.
- School of Biomedical Sciences, Kent State University, Kent, OH, USA.
- Brain Health Research Institute, Kent State University, Kent, OH, USA.
- Healthy Communities Research Institute, Kent State University, Kent, OH, USA.
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2
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Cuveillier C, Boulan B, Ravanello C, Denarier E, Deloulme JC, Gory-Fauré S, Delphin C, Bosc C, Arnal I, Andrieux A. Beyond Neuronal Microtubule Stabilization: MAP6 and CRMPS, Two Converging Stories. Front Mol Neurosci 2021; 14:665693. [PMID: 34025352 PMCID: PMC8131560 DOI: 10.3389/fnmol.2021.665693] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/09/2021] [Indexed: 12/21/2022] Open
Abstract
The development and function of the central nervous system rely on the microtubule (MT) and actin cytoskeletons and their respective effectors. Although the structural role of the cytoskeleton has long been acknowledged in neuronal morphology and activity, it was recently recognized to play the role of a signaling platform. Following this recognition, research into Microtubule Associated Proteins (MAPs) diversified. Indeed, historically, structural MAPs—including MAP1B, MAP2, Tau, and MAP6 (also known as STOP);—were identified and described as MT-binding and -stabilizing proteins. Extensive data obtained over the last 20 years indicated that these structural MAPs could also contribute to a variety of other molecular roles. Among multi-role MAPs, MAP6 provides a striking example illustrating the diverse molecular and cellular properties of MAPs and showing how their functional versatility contributes to the central nervous system. In this review, in addition to MAP6’s effect on microtubules, we describe its impact on the actin cytoskeleton, on neuroreceptor homeostasis, and its involvement in signaling pathways governing neuron development and maturation. We also discuss its roles in synaptic plasticity, brain connectivity, and cognitive abilities, as well as the potential relationships between the integrated brain functions of MAP6 and its molecular activities. In parallel, the Collapsin Response Mediator Proteins (CRMPs) are presented as examples of how other proteins, not initially identified as MAPs, fall into the broader MAP family. These proteins bind MTs as well as exhibiting molecular and cellular properties very similar to MAP6. Finally, we briefly summarize the multiple similarities between other classical structural MAPs and MAP6 or CRMPs.In summary, this review revisits the molecular properties and the cellular and neuronal roles of the classical MAPs, broadening our definition of what constitutes a MAP.
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3
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Deurveilher S, Ko KR, Saumure BSC, Robertson GS, Rusak B, Semba K. Altered circadian activity and sleep/wake rhythms in the stable tubule only polypeptide (STOP) null mouse model of schizophrenia. Sleep 2021; 44:5981350. [PMID: 33186470 DOI: 10.1093/sleep/zsaa237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 10/14/2020] [Indexed: 12/27/2022] Open
Abstract
Sleep and circadian rhythm disruptions commonly occur in individuals with schizophrenia. Stable tubule only polypeptide (STOP) knockout (KO) mice show behavioral impairments resembling symptoms of schizophrenia. We previously reported that STOP KO mice slept less and had more fragmented sleep and waking than wild-type littermates under a light/dark (LD) cycle. Here, we assessed the circadian phenotype of male STOP KO mice by examining wheel-running activity rhythms and EEG/EMG-defined sleep/wake states under both LD and constant darkness (DD) conditions. Wheel-running activity rhythms in KO and wild-type mice were similarly entrained in LD, and had similar free-running periods in DD. The phase delay shift in response to a light pulse given early in the active phase under DD was preserved in KO mice. KO mice had markedly lower activity levels, lower amplitude activity rhythms, less stable activity onsets, and more fragmented activity than wild-type mice in both lighting conditions. KO mice also spent more time awake and less time in rapid eye movement sleep (REMS) and non-REMS (NREMS) in both LD and DD conditions, with the decrease in NREMS concentrated in the active phase. KO mice also showed altered EEG features and higher amplitude rhythms in wake and NREMS (but not REMS) amounts in both lighting conditions, with a longer free-running period in DD, compared to wild-type mice. These results indicate that the STOP null mutation in mice altered the regulation of sleep/wake physiology and activity rhythm expression, but did not grossly disrupt circadian mechanisms.
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Affiliation(s)
- Samuel Deurveilher
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Kristin Robin Ko
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| | - Brock St C Saumure
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - George S Robertson
- Department of Psychiatry, Dalhousie University, Halifax, NS, Canada.,Department of Pharmacology, Dalhousie University, Halifax, NS, Canada
| | - Benjamin Rusak
- Department of Psychiatry, Dalhousie University, Halifax, NS, Canada.,Department of Psychology & Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Kazue Semba
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada.,Department of Psychiatry, Dalhousie University, Halifax, NS, Canada.,Department of Psychology & Neuroscience, Dalhousie University, Halifax, NS, Canada
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4
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Merenlender-Wagner A, Shemer Z, Touloumi O, Lagoudaki R, Giladi E, Andrieux A, Grigoriadis NC, Gozes I. New horizons in schizophrenia treatment: autophagy protection is coupled with behavioral improvements in a mouse model of schizophrenia. Autophagy 2015; 10:2324-32. [PMID: 25484074 DOI: 10.4161/15548627.2014.984274] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Autophagy plays a key role in the pathophysiology of schizophrenia as manifested by a 40% decrease in BECN1/Beclin 1 mRNA in postmortem hippocampal tissues relative to controls. This decrease was coupled with the deregulation of the essential ADNP (activity-dependent neuroprotector homeobox), a binding partner of MAP1LC3B/LC3B (microtubule-associated protein 1 light chain 3 β) another major constituent of autophagy. The drug candidate NAP (davunetide), a peptide fragment from ADNP, enhanced the ADNP-LC3B interaction. Parallel genetic studies have linked allelic variation in the gene encoding MAP6/STOP (microtubule-associated protein 6) to schizophrenia, along with altered MAP6/STOP protein expression in the schizophrenic brain and schizophrenic-like behaviors in Map6-deficient mice. In this study, for the first time, we reveal significant decreases in hippocampal Becn1 mRNA and reversal by NAP but not by the antipsychotic clozapine (CLZ) in Map6-deficient (Map6(+/-)) mice. Normalization of Becn1 expression by NAP was coupled with behavioral protection against hyperlocomotion and cognitive deficits measured in the object recognition test. CLZ reduced hyperlocomotion below control levels and did not significantly affect object recognition. The combination of CLZ and NAP resulted in normalized outcome behaviors. Phase II clinical studies have shown NAP-dependent augmentation of functional activities of daily living coupled with brain protection. The current studies provide a new mechanistic pathway and a novel avenue for drug development.
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Key Words
- ADNP, activity-dependent neuroprotector homeobox (human)
- Adnp, activity-dependent neuroprotective protein (mouse)
- Adnp2 (mouse), ADNP2 (human), ADNP homeobox 2
- Becn1 (mouse), BECN1 (human), Beclin 1, autophagy-related
- CLZ, clozapine
- HUGO gene nomenclature committee database)
- Hprt/Hprt1, hypoxanthine phosphoribosyl transferase
- MGI database)
- Map1lc3b (mouse), MAP1LC3B (human), microtubule-associated protein 1 light chain 3 β
- Map6 (mouse), MAP6 (human), microtubule-associated protein 6
- NAP (davunetide); object recognition
- activity-dependent neuroprotective protein (ADNP
- activity-dependent neuroprotector homeobox (ADNP
- hyperactivity; immunohistochemistry
- microtubule-associated protein 6 (MAP6)/stable tubule only polypeptide (STOP) deficiency
- real-time PCR
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Affiliation(s)
- Avia Merenlender-Wagner
- a The Adams Super Center for Brain Studies; The Lily and Avraham Gildor Chair for the Investigation of Growth Factors; The Elton Laboratory for Neuroendocrinology; Department of Human Molecular Genetics and Biochemistry; Sagol School of Neuroscience; Sackler Faculty of Medicine ; Tel Aviv University ; Tel Aviv ; Israel
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5
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Deloulme JC, Gory-Fauré S, Mauconduit F, Chauvet S, Jonckheere J, Boulan B, Mire E, Xue J, Jany M, Maucler C, Deparis AA, Montigon O, Daoust A, Barbier EL, Bosc C, Deglon N, Brocard J, Denarier E, Le Brun I, Pernet-Gallay K, Vilgrain I, Robinson PJ, Lahrech H, Mann F, Andrieux A. Microtubule-associated protein 6 mediates neuronal connectivity through Semaphorin 3E-dependent signalling for axonal growth. Nat Commun 2015; 6:7246. [PMID: 26037503 PMCID: PMC4468860 DOI: 10.1038/ncomms8246] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 04/22/2015] [Indexed: 01/07/2023] Open
Abstract
Structural microtubule associated proteins (MAPs) stabilize microtubules, a property that was thought to be essential for development, maintenance and function of neuronal circuits. However, deletion of the structural MAPs in mice does not lead to major neurodevelopment defects. Here we demonstrate a role for MAP6 in brain wiring that is independent of microtubule binding. We find that MAP6 deletion disrupts brain connectivity and is associated with a lack of post-commissural fornix fibres. MAP6 contributes to fornix development by regulating axonal elongation induced by Semaphorin 3E. We show that MAP6 acts downstream of receptor activation through a mechanism that requires a proline-rich domain distinct from its microtubule-stabilizing domains. We also show that MAP6 directly binds to SH3 domain proteins known to be involved in neurite extension and semaphorin function. We conclude that MAP6 is critical to interface guidance molecules with intracellular signalling effectors during the development of cerebral axon tracts. Loss of the structural microtubule-associated protein 6 (MAP6) leads to neuronal differentiation defects that are independent of MAP6's microtubule-binding properties. Here the authors establish a functional link between MAP6 and Semaphorin 3E signalling for proper formation of the fornix of the brain.
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Affiliation(s)
- Jean-Christophe Deloulme
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France
| | - Sylvie Gory-Fauré
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France
| | - Franck Mauconduit
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France
| | - Sophie Chauvet
- Aix-Marseille Université, CNRS, IBDM UMR 7288, 13288 Marseille, France
| | - Julie Jonckheere
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France
| | - Benoit Boulan
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France
| | - Erik Mire
- Aix-Marseille Université, CNRS, IBDM UMR 7288, 13288 Marseille, France
| | - Jing Xue
- Cell Signalling Unit, Children's Medical Research Institute, University of Sydney, Wentworthville, New South Wales 2145, Australia
| | - Marion Jany
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France
| | - Caroline Maucler
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France
| | - Agathe A Deparis
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France
| | - Olivier Montigon
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France [3] Centre Hospitalier Universitaire de Grenoble, IRMaGe, 38043 Grenoble, France [4] CNRS, UMS 3552, 38042 Grenoble, France
| | - Alexia Daoust
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France
| | - Emmanuel L Barbier
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France
| | - Christophe Bosc
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France
| | - Nicole Deglon
- 1] Lausanne University Hospital (CHUV), Department of Clinical Neurosciences (DNC), Laboratory of Cellular and Molecular Neurotherapies (LCMN), 1011 Lausanne, Switzerland [2] Lausanne University Hospital (CHUV), Neuroscience Research Center (CRN), 1011 Lausanne, Switzerland
| | - Jacques Brocard
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France
| | - Eric Denarier
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France [3] CEA, iRTSV, F-38000 Grenoble, France
| | - Isabelle Le Brun
- 1] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France [2] INSERM, U1036, 38054 Grenoble, France [3] CEA, iRTSV, F-38000 Grenoble, France
| | - Karin Pernet-Gallay
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France
| | - Isabelle Vilgrain
- 1] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France [2] INSERM, U1036, 38054 Grenoble, France [3] INSERM, U1036, 38054 Grenoble, France
| | - Phillip J Robinson
- Cell Signalling Unit, Children's Medical Research Institute, University of Sydney, Wentworthville, New South Wales 2145, Australia
| | - Hana Lahrech
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France [3] CEA, LETI, CLINATEC, MINATEC Campus, F-38054 Grenoble, France
| | - Fanny Mann
- Aix-Marseille Université, CNRS, IBDM UMR 7288, 13288 Marseille, France
| | - Annie Andrieux
- 1] INSERM, U836, F-38000 Grenoble, France [2] Univ. Grenoble Alpes, Grenoble Institut Neurosciences, F-38000 Grenoble, France [3] CEA, iRTSV, F-38000 Grenoble, France
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6
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Volle J, Brocard J, Saoud M, Gory-Faure S, Brunelin J, Andrieux A, Suaud-Chagny MF. Reduced expression of STOP/MAP6 in mice leads to cognitive deficits. Schizophr Bull 2013; 39:969-78. [PMID: 23002183 PMCID: PMC3756782 DOI: 10.1093/schbul/sbs113] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND STOP/MAP6 null (KO) mice recapitulate behavioral abnormalities related to positive and negative symptoms and cognitive deficits of schizophrenia. Here, we investigated whether decreased expression of STOP/MAP6 proteins in heterozygous mice (only one allele expressed) would result in abnormal behavior related to those displayed by STOP null mice. METHODS Using a comprehensive test battery, we investigated the behavioral phenotype of STOP heterozygous (Het) mice compared with STOP KO and wild type (WT) mice on animals raised either in standard conditions (controls) or submitted to maternal deprivation. RESULTS Control Het mice displayed prominent deficits in social interaction and learning, resembling KO mice. In contrast, they exhibited short-lasting locomotor hyperreactivity to acute mild stress and no impaired locomotor response to amphetamine, much like WT mice. Additionally, perinatal stress deteriorated Het mouse phenotype by exacerbating alterations related to positive symptoms such as their locomotor reactivity to acute mild stress and psychostimulant challenge. CONCLUSION Results show that the dosage of susceptibility genes modulates their putative phenotypic contribution and that STOP expression has a high penetrance on cognitive abilities. Hence, STOP Het mice might be useful to investigate cognitive defects related to those observed in mental diseases and ultimately might be a valuable experimental model to evaluate preventive treatments.
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Affiliation(s)
- Julien Volle
- Université de Lyon, Lyon, F-69003, France; Université Lyon 1, Lyon, EA 4615
| | - Jacques Brocard
- Institut National de la Santé et de la Recherche Médicale Unité 836, Institut des Neurosciences de Grenoble, Université Joseph Fourier, 38042 Grenoble Cedex 9, France;,Groupe Physiopathologie du Cytosquelette, Institut de Recherches en Technologies et Sciences pour le Vivant Direction des Sciences du Vivant, Commissariat à l’Énergie Atomique, 38054 Grenoble Cedex 9, France
| | - Mohamed Saoud
- Université de Lyon, Lyon, F-69003, France; Université Lyon 1, Lyon, EA 4615;,Centre Hospitalier le Vinatier, F-69677 Bron Cedex, France
| | - Sylvie Gory-Faure
- Institut National de la Santé et de la Recherche Médicale Unité 836, Institut des Neurosciences de Grenoble, Université Joseph Fourier, 38042 Grenoble Cedex 9, France;,Groupe Physiopathologie du Cytosquelette, Institut de Recherches en Technologies et Sciences pour le Vivant Direction des Sciences du Vivant, Commissariat à l’Énergie Atomique, 38054 Grenoble Cedex 9, France
| | - Jérôme Brunelin
- Université de Lyon, Lyon, F-69003, France; Université Lyon 1, Lyon, EA 4615;,Centre Hospitalier le Vinatier, F-69677 Bron Cedex, France
| | - Annie Andrieux
- Institut National de la Santé et de la Recherche Médicale Unité 836, Institut des Neurosciences de Grenoble, Université Joseph Fourier, 38042 Grenoble Cedex 9, France;,Groupe Physiopathologie du Cytosquelette, Institut de Recherches en Technologies et Sciences pour le Vivant Direction des Sciences du Vivant, Commissariat à l’Énergie Atomique, 38054 Grenoble Cedex 9, France
| | - Marie-Françoise Suaud-Chagny
- Université de Lyon, Lyon, F-69003, France; Université Lyon 1, Lyon, EA 4615;,Centre Hospitalier le Vinatier, F-69677 Bron Cedex, France;,To whom correspondence should be addressed; EA 4615, Pôle Est - Pr d’Amato, CH le vinatier, 95 bd Pinel, 69677 Bron cedex, France; tel: +33 4 37 91 55 65, fax: +33 4 37 91 55 49, e-mail:
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7
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Lefèvre J, Savarin P, Gans P, Hamon L, Clément MJ, David MO, Bosc C, Andrieux A, Curmi PA. Structural basis for the association of MAP6 protein with microtubules and its regulation by calmodulin. J Biol Chem 2013; 288:24910-22. [PMID: 23831686 DOI: 10.1074/jbc.m113.457267] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Microtubules are highly dynamic αβ-tubulin polymers. In vitro and in living cells, microtubules are most often cold- and nocodazole-sensitive. When present, the MAP6/STOP family of proteins protects microtubules from cold- and nocodazole-induced depolymerization but the molecular and structure determinants by which these proteins stabilize microtubules remain under debate. We show here that a short protein fragment from MAP6-N, which encompasses its Mn1 and Mn2 modules (MAP6(90-177)), recapitulates the function of the full-length MAP6-N protein toward microtubules, i.e. its ability to stabilize microtubules in vitro and in cultured cells in ice-cold conditions or in the presence of nocodazole. We further show for the first time, using biochemical assays and NMR spectroscopy, that these effects result from the binding of MAP6(90-177) to microtubules with a 1:1 MAP6(90-177):tubulin heterodimer stoichiometry. NMR data demonstrate that the binding of MAP6(90-177) to microtubules involve its two Mn modules but that a single one is also able to interact with microtubules in a closely similar manner. This suggests that the Mn modules represent each a full microtubule binding domain and that MAP6 proteins may stabilize microtubules by bridging tubulin heterodimers from adjacent protofilaments or within a protofilament. Finally, we demonstrate that Ca(2+)-calmodulin competes with microtubules for MAP6(90-177) binding and that the binding mode of MAP6(90-177) to microtubules and Ca(2+)-calmodulin involves a common stretch of amino acid residues on the MAP6(90-177) side. This result accounts for the regulation of microtubule stability in cold condition by Ca(2+)-calmodulin.
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Affiliation(s)
- Julien Lefèvre
- Institut National de la Santé et de la Recherche Médicale (INSERM), UMR829, Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, Université Evry-Val d'Essonne, Evry 91025, France.
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