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Ren Z, Hou J, Li W, Tang Y, Wang M, Ding R, Liu S, Fu Y, Mai Y, Xia J, Zuo W, Zhou LH, Ye JH, Fu R. LPA1 receptors in the lateral habenula regulate negative affective states associated with alcohol withdrawal. Neuropsychopharmacology 2023; 48:1567-1578. [PMID: 37059867 PMCID: PMC10516930 DOI: 10.1038/s41386-023-01582-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 02/17/2023] [Accepted: 03/30/2023] [Indexed: 04/16/2023]
Abstract
The role of lysophosphatidic acid (LPA) signaling in psychiatric disorders and drug abuse is significant. LPA receptors are widely expressed in the central nervous system, including the lateral habenula (LHb). Recent studies suggest that LHb is involved in a negative emotional state during alcohol withdrawal, which can lead to relapse. The current study examines the role of LHb LPA signaling in the negative affective state associated with alcohol withdrawal. Adult male Long-Evans rats were trained to consume either alcohol or water for eight weeks. At 48 h of withdrawal, alcohol-drinking rats showed anxiety- and depression-like symptoms, along with a significant increase in LPA signaling and related neuronal activation molecules, including autotaxin (ATX, Enpp2), LPA receptor 1/3 (LPA1/3), βCaMKII, and c-Fos. However, there was a decrease in lipid phosphate phosphatase-related protein type 4 (LPPR4) in the LHb. Intra-LHb infusion of the LPA1/3 receptor antagonist ki-16425 or PKC-γ inhibitor Go-6983 reduced the abnormal behaviors and elevated relapse-like ethanol drinking. It also normalized high LPA1/3 receptors and enhanced AMPA GluA1 phosphorylation in Ser831 and GluA1/GluA2 ratio. Conversely, selective activation of LPA1/3 receptors by intra-LHb infusion of 18:1 LPA induced negative affective states and upregulated βCaMKII-AMPA receptor phosphorylation in Naive rats, which were reversed by pretreatment with intra-LHb Go-6983. Our findings suggest that disturbances in LPA signaling contribute to adverse affective disorders during alcohol withdrawal, likely through PKC-γ/βCaMKII-linked glutamate signaling. Targeting LPA may therefore be beneficial for individuals suffering from alcohol use disorders.
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Affiliation(s)
- Zhiheng Ren
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518106, China
| | - Jiawei Hou
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518106, China
| | - Wenfu Li
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518106, China
| | - Ying Tang
- Department of Biology, School of Life Science, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Basic and Clinical Medicine Teaching Laboratory, School of Medicine, Sun Yat-sen University, Shenzhen, Guangdong, 518100, China
| | - Molin Wang
- Basic and Clinical Medicine Teaching Laboratory, School of Medicine, Sun Yat-sen University, Shenzhen, Guangdong, 518100, China
| | - Ruxuan Ding
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518106, China
| | - Songlin Liu
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518106, China
| | - Yixin Fu
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518106, China
| | - Yunlin Mai
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518106, China
| | - Jianxun Xia
- Department of Basic Medical Sciences, Yunkang School of Medicine and Health, Nanfang College, Guangzhou, Guangdong, 510970, China
| | - Wanhong Zuo
- Department of Anesthesiology, Pharmacology, Physiology & Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, NJ, 07103, USA
| | - Li-Hua Zhou
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518106, China
| | - Jiang-Hong Ye
- Department of Anesthesiology, Pharmacology, Physiology & Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, NJ, 07103, USA.
| | - Rao Fu
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518106, China.
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, 518106, China.
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2
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Yang C, Zhao X, An X, Zhang Y, Sun W, Zhang Y, Duan Y, Kang X, Sun Y, Jiang L, Lian F. Axonal transport deficits in the pathogenesis of diabetic peripheral neuropathy. Front Endocrinol (Lausanne) 2023; 14:1136796. [PMID: 37056668 PMCID: PMC10086245 DOI: 10.3389/fendo.2023.1136796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 03/14/2023] [Indexed: 03/30/2023] Open
Abstract
Diabetic peripheral neuropathy (DPN) is a chronic and prevalent metabolic disease that gravely endangers human health and seriously affects the quality of life of hyperglycemic patients. More seriously, it can lead to amputation and neuropathic pain, imposing a severe financial burden on patients and the healthcare system. Even with strict glycemic control or pancreas transplantation, peripheral nerve damage is difficult to reverse. Most current treatment options for DPN can only treat the symptoms but not the underlying mechanism. Patients with long-term diabetes mellitus (DM) develop axonal transport dysfunction, which could be an important factor in causing or exacerbating DPN. This review explores the underlying mechanisms that may be related to axonal transport impairment and cytoskeletal changes caused by DM, and the relevance of the latter with the occurrence and progression of DPN, including nerve fiber loss, diminished nerve conduction velocity, and impaired nerve regeneration, and also predicts possible therapeutic strategies. Understanding the mechanisms of diabetic neuronal injury is essential to prevent the deterioration of DPN and to develop new therapeutic strategies. Timely and effective improvement of axonal transport impairment is particularly critical for the treatment of peripheral neuropathies.
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Molecular Evolution, Neurodevelopmental Roles and Clinical Significance of HECT-Type UBE3 E3 Ubiquitin Ligases. Cells 2020; 9:cells9112455. [PMID: 33182779 PMCID: PMC7697756 DOI: 10.3390/cells9112455] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/03/2020] [Accepted: 11/07/2020] [Indexed: 12/12/2022] Open
Abstract
Protein ubiquitination belongs to the best characterized pathways of protein degradation in the cell; however, our current knowledge on its physiological consequences is just the tip of an iceberg. The divergence of enzymatic executors of ubiquitination led to some 600–700 E3 ubiquitin ligases embedded in the human genome. Notably, mutations in around 13% of these genes are causative of severe neurological diseases. Despite this, molecular and cellular context of ubiquitination remains poorly characterized, especially in the developing brain. In this review article, we summarize recent findings on brain-expressed HECT-type E3 UBE3 ligases and their murine orthologues, comprising Angelman syndrome UBE3A, Kaufman oculocerebrofacial syndrome UBE3B and autism spectrum disorder-associated UBE3C. We summarize evolutionary emergence of three UBE3 genes, the biochemistry of UBE3 enzymes, their biology and clinical relevance in brain disorders. Particularly, we highlight that uninterrupted action of UBE3 ligases is a sine qua non for cortical circuit assembly and higher cognitive functions of the neocortex.
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4
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Chung D, Shum A, Caraveo G. GAP-43 and BASP1 in Axon Regeneration: Implications for the Treatment of Neurodegenerative Diseases. Front Cell Dev Biol 2020; 8:567537. [PMID: 33015061 PMCID: PMC7494789 DOI: 10.3389/fcell.2020.567537] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/14/2020] [Indexed: 01/06/2023] Open
Abstract
Growth-associated protein-43 (GAP-43) and brain acid-soluble protein 1 (BASP1) regulate actin dynamics and presynaptic vesicle cycling at axon terminals, thereby facilitating axonal growth, regeneration, and plasticity. These functions highly depend on changes in GAP-43 and BASP1 expression levels and post-translational modifications such as phosphorylation. Interestingly, examinations of GAP-43 and BASP1 in neurodegenerative diseases reveal alterations in their expression and phosphorylation profiles. This review provides an overview of the structural properties, regulations, and functions of GAP-43 and BASP1, highlighting their involvement in neural injury response and regeneration. By discussing GAP-43 and BASP1 in the context of neurodegenerative diseases, we also explore the therapeutic potential of modulating their activities to compensate for neuron loss in neurodegenerative diseases.
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Affiliation(s)
- Daayun Chung
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Andrew Shum
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Gabriela Caraveo
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
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5
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Turner M, Anderson DE, Bartels P, Nieves-Cintron M, Coleman AM, Henderson PB, Man KNM, Tseng PY, Yarov-Yarovoy V, Bers DM, Navedo MF, Horne MC, Ames JB, Hell JW. α-Actinin-1 promotes activity of the L-type Ca 2+ channel Ca v 1.2. EMBO J 2020; 39:e102622. [PMID: 31985069 DOI: 10.15252/embj.2019102622] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 12/04/2019] [Accepted: 12/06/2019] [Indexed: 01/05/2023] Open
Abstract
The L-type Ca2+ channel CaV 1.2 governs gene expression, cardiac contraction, and neuronal activity. Binding of α-actinin to the IQ motif of CaV 1.2 supports its surface localization and postsynaptic targeting in neurons. We report a bi-functional mechanism that restricts CaV 1.2 activity to its target sites. We solved separate NMR structures of the IQ motif (residues 1,646-1,664) bound to α-actinin-1 and to apo-calmodulin (apoCaM). The CaV 1.2 K1647A and Y1649A mutations, which impair α-actinin-1 but not apoCaM binding, but not the F1658A and K1662E mutations, which impair apoCaM but not α-actinin-1 binding, decreased single-channel open probability, gating charge movement, and its coupling to channel opening. Thus, α-actinin recruits CaV 1.2 to defined surface regions and simultaneously boosts its open probability so that CaV 1.2 is mostly active when appropriately localized.
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Affiliation(s)
- Matthew Turner
- Department of Chemistry, University of California, Davis, CA, USA
| | - David E Anderson
- Department of Chemistry, University of California, Davis, CA, USA
| | - Peter Bartels
- Department of Pharmacology, University of California, Davis, CA, USA
| | | | - Andrea M Coleman
- Department of Chemistry, University of California, Davis, CA, USA.,Department of Pharmacology, University of California, Davis, CA, USA
| | - Peter B Henderson
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Kwun Nok Mimi Man
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Pang-Yen Tseng
- Department of Pharmacology, University of California, Davis, CA, USA
| | | | - Donald M Bers
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Mary C Horne
- Department of Pharmacology, University of California, Davis, CA, USA
| | - James B Ames
- Department of Chemistry, University of California, Davis, CA, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, CA, USA
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6
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Holahan MR. A Shift from a Pivotal to Supporting Role for the Growth-Associated Protein (GAP-43) in the Coordination of Axonal Structural and Functional Plasticity. Front Cell Neurosci 2017; 11:266. [PMID: 28912688 PMCID: PMC5583208 DOI: 10.3389/fncel.2017.00266] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 08/18/2017] [Indexed: 11/14/2022] Open
Abstract
In a number of animal species, the growth-associated protein (GAP), GAP-43 (aka: F1, neuromodulin, B-50, G50, pp46), has been implicated in the regulation of presynaptic vesicular function and axonal growth and plasticity via its own biochemical properties and interactions with a number of other presynaptic proteins. Changes in the expression of GAP-43 mRNA or distribution of the protein coincide with axonal outgrowth as a consequence of neuronal damage and presynaptic rearrangement that would occur following instances of elevated patterned neural activity including memory formation and development. While functional enhancement in GAP-43 mRNA and/or protein activity has historically been hypothesized as a central mediator of axonal neuroplastic and regenerative responses in the central nervous system, it does not appear to be the crucial substrate sufficient for driving these responses. This review explores the historical discovery of GAP-43 (and associated monikers), its transcriptional, post-transcriptional and post-translational regulation and current understanding of protein interactions and regulation with respect to its role in axonal function. While GAP-43 itself appears to have moved from a pivotal to a supporting factor, there is no doubt that investigations into its functions have provided a clearer understanding of the biochemical underpinnings of axonal plasticity.
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7
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Callender J, Newton A. Conventional protein kinase C in the brain: 40 years later. Neuronal Signal 2017; 1:NS20160005. [PMID: 32714576 PMCID: PMC7373245 DOI: 10.1042/ns20160005] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/02/2017] [Accepted: 03/07/2017] [Indexed: 12/16/2022] Open
Abstract
Protein kinase C (PKC) is a family of enzymes whose members transduce a large variety of cellular signals instigated by the receptor-mediated hydrolysis of membrane phospholipids. While PKC has been widely implicated in the pathology of diseases affecting all areas of physiology including cancer, diabetes, and heart disease-it was discovered, and initially characterized, in the brain. PKC plays a key role in controlling the balance between cell survival and cell death. Its loss of function is generally associated with cancer, whereas its enhanced activity is associated with neurodegeneration. This review presents an overview of signaling by diacylglycerol (DG)-dependent PKC isozymes in the brain, and focuses on the role of the Ca2+-sensitive conventional PKC isozymes in neurodegeneration.
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Affiliation(s)
- Julia A. Callender
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0721, U.S.A
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093-0721, U.S.A
| | - Alexandra C. Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0721, U.S.A
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8
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Caprara GA, Morabito C, Perni S, Navarra R, Guarnieri S, Mariggiò MA. Evidence for Altered Ca 2+ Handling in Growth Associated Protein 43-Knockout Skeletal Muscle. Front Physiol 2016; 7:493. [PMID: 27833566 PMCID: PMC5080375 DOI: 10.3389/fphys.2016.00493] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/11/2016] [Indexed: 11/13/2022] Open
Abstract
Neuronal growth-associated protein 43 (GAP43) has crucial roles in the nervous system, and during development, regeneration after injury, and learning and memory. GAP43 is expressed in mouse skeletal muscle fibers and satellite cells, with suggested its involvement in intracellular Ca2+ handling. However, the physiological role of GAP43 in muscle remains unknown. Using a GAP43-knockout (GAP43-/-) mouse, we have defined the role of GAP43 in skeletal muscle. GAP43-/- mice showed low survival beyond weaning, reduced adult body weight, decreased muscle strength, and changed myofiber ultrastructure, with no significant differences in the expression of markers of satellite cell and myotube progression through the myogenic program. Thus, GAP43 expression is involved in timing of muscle maturation in-vivo. Intracellular Ca2+ measurements in-vitro in myotubes revealed GAP43 involvement in Ca2+ handling. In the absence of GAP43 expression, the spontaneous Ca2+ variations had greater amplitudes and higher frequency. In GAP43-/- myotubes, also the intracellular Ca2+ variations induced by the activation of dihydropyridine and ryanodine Ca2+ channels, resulted modified. These evidences suggested dysregulation of Ca2+ homeostasis. The emerging hypothesis indicates that GAP43 interacts with calmodulin to indirectly modulate the activities of dihydropyridine and ryanodine Ca2+ channels. This thus influences intracellular Ca2+ dynamics and its related intracellular patterns, from functional excitation-contraction coupling, to cell metabolism, and gene expression.
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Affiliation(s)
- Giusy A Caprara
- Laboratory of Functional Biotechnology, Center of Sciences on Aging and Translational Medicine (CeSI-MeT), Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
| | - Caterina Morabito
- Laboratory of Functional Biotechnology, Center of Sciences on Aging and Translational Medicine (CeSI-MeT), Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
| | - Stefano Perni
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA
| | - Riccardo Navarra
- Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
| | - Simone Guarnieri
- Laboratory of Functional Biotechnology, Center of Sciences on Aging and Translational Medicine (CeSI-MeT), Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
| | - Maria A Mariggiò
- Laboratory of Functional Biotechnology, Center of Sciences on Aging and Translational Medicine (CeSI-MeT), Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
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9
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Forsova OS, Zakharov VV. High-order oligomers of intrinsically disordered brain proteins BASP1 and GAP-43 preserve the structural disorder. FEBS J 2016; 283:1550-69. [PMID: 26918762 DOI: 10.1111/febs.13692] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/26/2016] [Accepted: 02/23/2016] [Indexed: 11/30/2022]
Abstract
Brain acid-soluble protein-1 (BASP1) and growth-associated protein-43 (GAP-43) are presynaptic membrane proteins participating in axon guidance, neuroregeneration and synaptic plasticity. They are presumed to sequester phosphatidylinositol-4,5-bisphosphate (PIP2 ) in lipid rafts. Previously we have shown that the proteins form heterogeneously sized oligomers in the presence of anionic phospholipids or SDS at submicellar concentration. BASP1 and GAP-43 are intrinsically disordered proteins (IDPs). In light of this, we investigated the structure of their oligomers. Using partial cross-linking of the oligomers with glutaraldehyde, the aggregation numbers of BASP1 and GAP-43 were estimated as 10-14 and 6-7 monomer subunits, respectively. The cross-linking pattern indicated that the subunits are circularly arranged. The circular dichroism (CD) spectra of the monomers were characteristic of coil-like IDPs showing unordered structure with a high population of polyproline-II conformation. The oligomerization was accompanied by a minor CD spectral change attributable to formation of a small amount of α-helix. The number of residues in the α-helical conformation was estimated as 13 in BASP1 and 18 in GAP-43. However, the overall structure of the oligomers remained disordered, indicating a high degree of 'fuzziness'. This was confirmed by measuring the hydrodynamic dimensions of the oligomers using polyacrylamide gradient gel electrophoresis and size-exclusion chromatography, and by assaying their sensitivity to proteolytic digestion. There is evidence that the observed α-helical folding occurs within the basic effector domains, which are presumably tethered together via anionic molecules of SDS or PIP2 . We conclude that BASP1 and GAP-43 oligomers preserve a mostly disordered structure, which may be of great importance for their function in PIP2 signaling pathway.
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Affiliation(s)
- Oksana S Forsova
- Molecular and Radiation Biophysics Division, B. P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre 'Kurchatov Institute', Gatchina, Russia.,Laboratory of Natural Polymers, Institute of Macromolecular Compounds, Russian Academy of Sciences, St Petersburg, Russia
| | - Vladislav V Zakharov
- Molecular and Radiation Biophysics Division, B. P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre 'Kurchatov Institute', Gatchina, Russia.,Laboratory of Natural Polymers, Institute of Macromolecular Compounds, Russian Academy of Sciences, St Petersburg, Russia.,Department of Biophysics, Institute of Physics, Nanotechnology and Telecommunications, Peter the Great St Petersburg Polytechnic University, Russia
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10
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De Moliner K, Wolfson ML, Perrone-Bizzozero N, Adamo AM. GAP-43 slows down cell cycle progression via sequences in its 3'UTR. Arch Biochem Biophys 2015; 571:66-75. [PMID: 25721498 DOI: 10.1016/j.abb.2015.02.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 01/30/2015] [Accepted: 02/18/2015] [Indexed: 12/26/2022]
Abstract
Growth-associated protein 43 (GAP-43) is a neuronal phosphoprotein associated with initial axonal outgrowth and synaptic remodeling and recent work also suggests its involvement in cell cycle control. The complex expression of GAP-43 features transcriptional and posttranscriptional components. However, in some conditions, GAP-43 gene expression is controlled primarily by the interaction of stabilizing or destabilizing RNA-binding proteins (RBPs) with adenine and uridine (AU)-rich instability elements (AREs) in its 3'UTR. Like GAP-43, many proteins involved in cell proliferation are encoded by ARE-containing mRNAs, some of which codify cell-cycle-regulating proteins including cyclin D1. Considering that GAP-43 and cyclin D1 mRNA stabilization may depend on similar RBPs, this study evaluated the participation of GAP-43 in cell cycle control and its underlying mechanisms, particularly the possible role of its 3'UTR, using GAP-43-transfected NIH-3T3 fibroblasts. Our results show an arrest in cell cycle progression in the G0/G1 phase. This arrest may be mediated by the competition of GAP-43 3'UTR with cyclin D1 3'UTR for the binding of Hu proteins such as HuR, which may lead to a decrease in cyclin D1 expression. These results might lead to therapeutic applications involving the use of sequences in the B region of GAP-43 3'UTR to slow down cell cycle progression.
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Affiliation(s)
- Karina De Moliner
- Department of Biological Chemistry, IQUIFIB (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Junín 956, C1113AAD Buenos Aires, Argentina
| | - Manuel Luis Wolfson
- Department of Biological Chemistry, IQUIFIB (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Junín 956, C1113AAD Buenos Aires, Argentina
| | - Nora Perrone-Bizzozero
- Department of Neurosciences and Psychiatry, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | - Ana M Adamo
- Department of Biological Chemistry, IQUIFIB (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Junín 956, C1113AAD Buenos Aires, Argentina.
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11
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Hoffman L, Chandrasekar A, Wang X, Putkey JA, Waxham MN. Neurogranin alters the structure and calcium binding properties of calmodulin. J Biol Chem 2014; 289:14644-55. [PMID: 24713697 DOI: 10.1074/jbc.m114.560656] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Neurogranin (Ng) is a member of the IQ motif class of calmodulin (CaM)-binding proteins, and interactions with CaM are its only known biological function. In this report we demonstrate that the binding affinity of Ng for CaM is weakened by Ca(2+) but to a lesser extent (2-3-fold) than that previously suggested from qualitative observations. We also show that Ng induced a >10-fold decrease in the affinity of Ca(2+) binding to the C-terminal domain of CaM with an associated increase in the Ca(2+) dissociation rate. We also discovered a modest, but potentially important, increase in the cooperativity in Ca(2+) binding to the C-lobe of CaM in the presence of Ng, thus sharpening the threshold for the C-domain to become Ca(2+)-saturated. Domain mapping using synthetic peptides indicated that the IQ motif of Ng is a poor mimetic of the intact protein and that the acidic sequence just N-terminal to the IQ motif plays an important role in reproducing Ng-mediated decreases in the Ca(2+) binding affinity of CaM. Using NMR, full-length Ng was shown to make contacts largely with residues in the C-domain of CaM, although contacts were also detected in residues in the N-terminal domain. Together, our results can be consolidated into a model where Ng contacts residues in the N- and C-lobes of both apo- and Ca(2+)-bound CaM and that although Ca(2+) binding weakens Ng interactions with CaM, the most dramatic biochemical effect is the impact of Ng on Ca(2+) binding to the C-terminal lobe of CaM.
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Affiliation(s)
| | | | - Xu Wang
- Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, Texas 77030
| | - John A Putkey
- Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, Texas 77030
| | - M Neal Waxham
- From the Departments of Neurobiology and Anatomy and
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12
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Kumar V, Chichili VPR, Tang X, Sivaraman J. A novel trans conformation of ligand-free calmodulin. PLoS One 2013; 8:e54834. [PMID: 23382982 PMCID: PMC3558517 DOI: 10.1371/journal.pone.0054834] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 12/19/2012] [Indexed: 11/24/2022] Open
Abstract
Calmodulin (CaM) is a highly conserved eukaryotic protein that binds specifically to more than 100 target proteins in response to calcium (Ca2+) signal. CaM adopts a considerable degree of structural plasticity to accomplish this physiological role; however, the nature and extent of this plasticity remain to be fully understood. Here, we report the crystal structure of a novel trans conformation of ligand-free CaM where the relative disposition of two lobes of CaM is different, a conformation to-date not reported. While no major structural changes were observed in the independent N- and C-lobes as compared with previously reported structures of Ca2+/CaM, the central helix was tilted by ∼90° at Arg75. This is the first crystal structure of CaM to show a drastic conformational change in the central helix, and reveals one of several possible conformations of CaM to engage with its binding partner.
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Affiliation(s)
- Veerendra Kumar
- Department of Biological Sciences, National University of Singapore, Republic of Singapore, Republic of Singapore
| | | | - Xuhua Tang
- Department of Biological Sciences, National University of Singapore, Republic of Singapore, Republic of Singapore
| | - J. Sivaraman
- Department of Biological Sciences, National University of Singapore, Republic of Singapore, Republic of Singapore
- * E-mail:
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13
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Guarnieri S, Morabito C, Paolini C, Boncompagni S, Pilla R, Fanò-Illic G, Mariggiò MA. Growth associated protein 43 is expressed in skeletal muscle fibers and is localized in proximity of mitochondria and calcium release units. PLoS One 2013; 8:e53267. [PMID: 23308181 PMCID: PMC3538766 DOI: 10.1371/journal.pone.0053267] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 11/27/2012] [Indexed: 11/26/2022] Open
Abstract
The neuronal Growth Associated Protein 43 (GAP43), also known as B-50 or neuromodulin, is involved in mechanisms controlling pathfinding and branching of neurons during development and regeneration. For many years this protein was classified as neuron-specific, but recent evidences suggest that a) GAP43 is expressed in the nervous system not only in neurons, but also in glial cells, and b) probably it is present also in other tissues. In particular, its expression was revealed in muscles from patients affected by various myopathies, indicating that GAP43 can no-longer considered only as a neuron-specific molecule. We have investigated the expression and subcellular localization of GAP43 in mouse satellite cells, myotubes, and adult muscle (extensor digitorum longus or EDL) using Western blotting, immuno-fluorescence combined to confocal microscopy and electron microscopy. Our in vitro results indicated that GAP43 is indeed expressed in both myoblasts and differentiating myotubes, and its cellular localization changes dramatically during maturation: in myoblasts the localization appeared to be mostly nuclear, whereas with differentiation the protein started to display a sarcomeric-like pattern. In adult fibers, GAP43 expression was evident with the protein labeling forming (in longitudinal views) a double cross striation reminiscent of the staining pattern of other organelles, such as calcium release units (CRUs) and mitochondria. Double immuno-staining and experiments done in EDL muscles fixed at different sarcomere lengths, allowed us to determine the localization, from the sarcomere Z-line, of GAP43 positive foci, falling between that of CRUs and of mitochondria. Staining of cross sections added a detail to the puzzle: GAP43 labeling formed a reticular pattern surrounding individual myofibrils, but excluding contractile elements. This work leads the way to further investigation about the possible physiological and structural role of GAP43 protein in adult fiber function and disease.
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Affiliation(s)
- Simone Guarnieri
- Department of Neuroscience and Imaging (DNI), University G. d’Annunzio, Chieti, Italy
- Center for Research on Ageing (CeSI), University G. d’Annunzio, Chieti, Italy
- Interuniversitary Institute of Myology (IIM), University G. d’Annunzio, Chieti, Italy
| | - Caterina Morabito
- Department of Neuroscience and Imaging (DNI), University G. d’Annunzio, Chieti, Italy
- Center for Research on Ageing (CeSI), University G. d’Annunzio, Chieti, Italy
- Interuniversitary Institute of Myology (IIM), University G. d’Annunzio, Chieti, Italy
| | - Cecilia Paolini
- Department of Neuroscience and Imaging (DNI), University G. d’Annunzio, Chieti, Italy
- Center for Research on Ageing (CeSI), University G. d’Annunzio, Chieti, Italy
- Interuniversitary Institute of Myology (IIM), University G. d’Annunzio, Chieti, Italy
| | - Simona Boncompagni
- Department of Neuroscience and Imaging (DNI), University G. d’Annunzio, Chieti, Italy
- Center for Research on Ageing (CeSI), University G. d’Annunzio, Chieti, Italy
- Interuniversitary Institute of Myology (IIM), University G. d’Annunzio, Chieti, Italy
| | - Raffaele Pilla
- Center for Research on Ageing (CeSI), University G. d’Annunzio, Chieti, Italy
- Interuniversitary Institute of Myology (IIM), University G. d’Annunzio, Chieti, Italy
| | - Giorgio Fanò-Illic
- Department of Neuroscience and Imaging (DNI), University G. d’Annunzio, Chieti, Italy
- Center for Research on Ageing (CeSI), University G. d’Annunzio, Chieti, Italy
- Interuniversitary Institute of Myology (IIM), University G. d’Annunzio, Chieti, Italy
| | - Maria A. Mariggiò
- Department of Neuroscience and Imaging (DNI), University G. d’Annunzio, Chieti, Italy
- Center for Research on Ageing (CeSI), University G. d’Annunzio, Chieti, Italy
- Interuniversitary Institute of Myology (IIM), University G. d’Annunzio, Chieti, Italy
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Wang X, Xiong LW, El Ayadi A, Boehning D, Putkey JA. The calmodulin regulator protein, PEP-19, sensitizes ATP-induced Ca2+ release. J Biol Chem 2012. [PMID: 23204517 DOI: 10.1074/jbc.m112.411314] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
PEP-19 is a small, intrinsically disordered protein that binds to the C-domain of calmodulin (CaM) via an IQ motif and tunes its Ca(2+) binding properties via an acidic sequence. We show here that the acidic sequence of PEP-19 has intrinsic Ca(2+) binding activity, which may modulate Ca(2+) binding to CaM by stabilizing an initial Ca(2+)-CaM complex or by electrostatically steering Ca(2+) to and from CaM. Because PEP-19 is expressed in cells that exhibit highly active Ca(2+) dynamics, we tested the hypothesis that it influences ligand-dependent Ca(2+) release. We show that PEP-19 increases the sensitivity of HeLa cells to ATP-induced Ca(2+) release to greatly increase the percentage of cells responding to sub-saturating doses of ATP and increases the frequency of Ca(2+) oscillations. Mutations in the acidic sequence of PEP-19 that inhibit or prevent it from modulating Ca(2+) binding to CaM greatly inhibit its effect on ATP-induced Ca(2+) release. Thus, this cellular effect of PEP-19 does not depend simply on binding to CaM via the IQ motif but requires its acidic metal binding domain. Tuning the activities of Ca(2+) mobilization pathways places PEP-19 at the top of CaM signaling cascades, with great potential to exert broad effects on downstream CaM targets, thus expanding the biological significance of this small regulator of CaM signaling.
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Affiliation(s)
- Xu Wang
- Department of Biochemistry and Molecular Biology and Structural Biology Imaging Center, University of Texas Medical School, Houston, Texas 77030, USA
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15
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Baumgärtel K, Mansuy IM. Neural functions of calcineurin in synaptic plasticity and memory. Learn Mem 2012; 19:375-84. [PMID: 22904368 DOI: 10.1101/lm.027201.112] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Major brain functions depend on neuronal processes that favor the plasticity of neuronal circuits while at the same time maintaining their stability. The mechanisms that regulate brain plasticity are complex and engage multiple cascades of molecular components that modulate synaptic efficacy. Protein kinases (PKs) and phosphatases (PPs) are among the most important of these components that act as positive and negative regulators of neuronal signaling and plasticity, respectively. In these cascades, the PP protein phosphatase 2B or calcineurin (CaN) is of particular interest because it is the only Ca(2+)-activated PP in the brain and a major regulator of key proteins essential for synaptic transmission and neuronal excitability. This review describes the primary properties of CaN and illustrates its functions and modes of action by focusing on several representative targets, in particular glutamate receptors, striatal enriched protein phosphatase (STEP), and neuromodulin (GAP43), and their functional significance for synaptic plasticity and memory.
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Affiliation(s)
- Karsten Baumgärtel
- Dorris Neuroscience Center, Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037-1000, USA
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Morgan MAJ, Morgan JI. Pcp4l1 contains an auto-inhibitory element that prevents its IQ motif from binding to calmodulin. J Neurochem 2012; 121:843-51. [PMID: 22458599 DOI: 10.1111/j.1471-4159.2012.07745.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Purkinje cell protein 4-like 1 (Pcp4l1) is a small neuronal IQ motif protein closely related to the calmodulin-binding protein Pcp4/PEP-19. PEP-19 interacts with calmodulin via its IQ motif to inhibit calmodulin-dependent enzymes and we hypothesized Pcp4l1 would have similar properties. Surprisingly, full-length Pcp4l1 does not interact with calmodulin in yeast two-hybrid or pulldown experiments yet a synthetic peptide constituting only the IQ motif of Pcp4l1 binds calmodulin and inhibits calmodulin-dependent kinase II. A nine-residue glutamic acid-rich sequence in Pcp4l1 confers these unexpected properties. This element lies outside the IQ motif and its deletion or exchange with the homologous region of PEP-19 restores calmodulin binding. Conversion of a single isoleucine (Ile36) within this motif to phenylalanine, the residue present in PEP-19, imparts calmodulin binding onto Pcp4l1. Moreover, only aromatic amino acid substitutions at position 36 in Pcp4l1 allow binding. Thus, despite their sequence similarities PEP-19 and Pcp4l1 have distinct properties with the latter harboring an element that can functionally suppress an IQ motif. We speculate Pcp4l1 may be a latent calmodulin inhibitor regulated by post-translational modification and/or co-factor interactions.
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Affiliation(s)
- Marc A J Morgan
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
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Jang DJ, Ban B, Lee JA. Characterization of novel calmodulin binding domains within IQ motifs of IQGAP1. Mol Cells 2011; 32:511-8. [PMID: 22080369 PMCID: PMC3887683 DOI: 10.1007/s10059-011-0109-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Revised: 09/22/2011] [Accepted: 09/22/2011] [Indexed: 12/11/2022] Open
Abstract
IQ motif-containing GTPase-activating protein 1 (IQGAP1), which is a well-known calmodulin (CaM) binding protein, is involved in a wide range of cellular processes including cell proliferation, tumorigenesis, adhesion, and migration. Interaction of IQGAP1 with CaM is important for its cellular functions. Although each IQ domain of IQGAP1 for CaM binding has been characterized in a Ca(2+)-dependent or -independent manner, it was not clear which IQ motifs are physiologically relevant for CaM binding in the cells. In this study, we performed immunoprecipitation using 3xFLAGhCaM in mammalian cell lines to characterize the domains of IQGAP1 that are key for CaM binding under physiological conditions. Interestingly, using this method, we identified two novel domains, IQ(2.7-3) and IQ(3.5-4.4), within IQGAP1 that were involved in Ca(2+)-independent or -dependent CaM binding, respectively. Mutant analysis clearly showed that the hydrophobic regions within IQ(2.7-3) were mainly involved in apoCaM binding, while the basic amino acids and hydrophobic region of IQ(3.5-4.4) were required for Ca(2+)/CaM binding. Finally, we showed that IQ(2.7-3) was the main apoCaM binding domain and both IQ(2.7-3) and IQ(3.5-4.4) were required for Ca(2+)/CaM binding within IQ(1-2-3-4). Thus, we identified and characterized novel direct CaM binding motifs essential for IQGAP1. This finding indicates that IQGAP1 plays a dynamic role via direct interactions with CaM in a Ca(2+)-dependent or -independent manner.
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Affiliation(s)
- Deok-Jin Jang
- Department of Applied Biology, College of Ecology and Environment, Kyungpook National University, Daegu 742-711, Korea
- These authors contributed equally to this work
| | - Byungkwan Ban
- Department of Biotechnology, College of Life Science and Nano Technology, Hannam University, Daejeon 305-811, Korea
- These authors contributed equally to this work
| | - Jin-A Lee
- Department of Biotechnology, College of Life Science and Nano Technology, Hannam University, Daejeon 305-811, Korea
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Szeltner Z, Morawski M, Juhász T, Szamosi I, Liliom K, Csizmók V, Tölgyesi F, Polgár L. GAP43 shows partial co-localisation but no strong physical interaction with prolyl oligopeptidase. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1804:2162-76. [PMID: 20869470 DOI: 10.1016/j.bbapap.2010.09.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 09/08/2010] [Accepted: 09/15/2010] [Indexed: 11/13/2022]
Abstract
It has recently been proposed that prolyl oligopeptidase (POP), the cytosolic serine peptidase with neurological implications, binds GAP43 (Growth-Associated Protein 43) and is implicated in neuronal growth cone formation, axon guidance and synaptic plasticity. We investigated the interaction between GAP43 and POP with various biophysical and biochemical methods in vitro and studied the co-localisation of the two proteins in differentiated HeLa cells. GAP43 and POP showed partial co-localisation in the cell body as well as in the potential growth cone structures. We could not detect significant binding between the recombinantly expressed POP and GAP43 using gel filtration, CD, ITC and BIACORE studies, pull-down experiments, glutaraldehyde cross-linking and limited proteolysis. However, glutaraldehyde cross-linking suggested a weak and transient interaction between the proteins. Both POP and GAP43 interacted with artificial lipids in our in vitro model system, but the presence of lipids did not evoke binding between them. In native polyacrylamide gel electrophoresis, GAP43 interacted with one of the three forms of a polyhistidine-tagged prolyl oligopeptidase. The interaction of the two proteins was also evident in ELISA and we have observed co-precipitation of the two proteins during co-incubation at higher concentrations. Our results indicate that there is no strong and direct interaction between POP and GAP43 at physiological conditions.
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Affiliation(s)
- Zoltán Szeltner
- Institute of Enzymology, BRC, Hungarian Academy of Sciences, Budapest, H-1113, Karolina út 29, Hungary.
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19
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Is the lifetime of light-stimulated cGMP phosphodiesterase regulated by recoverin through its regulation of rhodopsin phosphorylation? Behav Brain Sci 2010. [DOI: 10.1017/s0140525x00039522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Oligomeric structure of brain abundant proteins GAP-43 and BASP1. J Struct Biol 2010; 170:470-83. [PMID: 20109554 DOI: 10.1016/j.jsb.2010.01.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 12/21/2009] [Accepted: 01/20/2010] [Indexed: 11/19/2022]
Abstract
Brain abundant proteins GAP-43 and BASP1 participate in the regulation of actin cytoskeleton dynamics in neuronal axon terminals. The proposed mechanism suggests that the proteins sequester phosphatidylinositol-4,5-diphosphate (PIP(2)) in the inner leaflet of the plasma membrane. We found that model anionic phospholipid membranes in the form of liposomes induce rapid oligomerization of GAP-43 and BASP1 proteins. Multiply charged phosphoinositides produced the most potent effect. Anionic detergent sodium dodecyl sulfate (SDS) at submicellar concentration stimulated formation of similar oligomers in solution. BASP1, but not GAP-43, also formed oligomers at sufficiently high concentration in the absence of lipids and SDS. Electron microscopy study demonstrated that the oligomers have disk-shaped or annular structure of 10-30nm in diameter. BASP1 also formed higher aggregates of linear rod-like structure, with average length of about 100nm. In outward appearance, the oligomers and linear aggregates are reminiscent of oligomers and protofibrils of amyloid proteins. Both the synthetic N-terminal peptide GAP-43(1-40) and the brain-derived fragment GAP-43-3 preserved the ability to oligomerize under the action of acidic phospholipids and SDS. On the contrary, BASP1 fragment truncated by the short N-terminal myristoylated peptide was unable to form oligomers. GAP-43 and BASP1 oligomerization can be regulated by calmodulin, which disrupts the oligomers and displaces the proteins from the membrane. We suggest that in vivo, the role of membrane-bound GAP-43 and BASP1 oligomers consists in accumulation of PIP(2) in functional clusters, which become accessible for other PIP(2)-binding proteins after dissociation of the oligomers.
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Tanner DC, Qiu S, Bolognani F, Partridge LD, Weeber EJ, Perrone-Bizzozero NI. Alterations in mossy fiber physiology and GAP-43 expression and function in transgenic mice overexpressing HuD. Hippocampus 2008; 18:814-23. [PMID: 18493953 DOI: 10.1002/hipo.20442] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
HuD is a neuronal RNA-binding protein associated with the stabilization of mRNAs for GAP-43 and other neuronal proteins that are important for nervous system development and learning and memory mechanisms. To better understand the function of this protein, we generated transgenic mice expressing human HuD (HuD-Tg) in adult forebrain neurons. We have previously shown that expression of HuD in adult dentate granule cells results in an abnormal accumulation of GAP-43 mRNA via posttranscriptional mechanisms. Here we show that this mRNA accumulation leads to the ectopic expression of GAP-43 protein in mossy fibers. Electrophysiological analyses of the mossy fiber to CA3 synapse of HuD-Tg mice revealed increases in paired-pulse facilitation (PPF) at short interpulse intervals and no change in long-term potentiation (LTP). Presynaptic calcium transients at the same synapses exhibited faster time constants of decay, suggesting a decrease in the endogenous Ca(2+) buffer capacity of mossy fiber terminals of HuD-Tg mice. Under resting conditions, GAP-43 binds very tightly to calmodulin sequestering it and then releasing it upon PKC-dependent phosphorylation. Therefore, subsequent studies examined the extent of GAP-43 phosphorylation and its association to calmodulin. We found that despite the increased GAP-43 expression in HuD-Tg mice, the levels of PKC-phosphorylated GAP-43 were decreased in these animals. Furthermore, in agreement with the increased proportion of nonphosphorylated GAP-43, HuD-Tg mice showed increased binding of calmodulin to this protein. These results suggest that a significant amount of calmodulin may be trapped in an inactive state, unable to bind free calcium, and activate downstream signaling pathways. In conclusion, we propose that an unregulated expression of HuD disrupts mossy fiber physiology in adult mice in part by altering the expression and phosphorylation of GAP-43 and the amount of free calmodulin available at the synaptic terminal.
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Affiliation(s)
- Daniel C Tanner
- Department of Neurosciences, University of New Mexico HSC, Albuquerque, New Mexico 87106, USA
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Ishida H, Borman MA, Ostrander J, Vogel HJ, MacDonald JA. Solution structure of the calponin homology (CH) domain from the smoothelin-like 1 protein: a unique apocalmodulin-binding mode and the possible role of the C-terminal type-2 CH-domain in smooth muscle relaxation. J Biol Chem 2008; 283:20569-78. [PMID: 18477568 DOI: 10.1074/jbc.m800627200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The SMTNL1 protein contains a single type-2 calponin homology (CH) domain at its C terminus that shares sequence identity with the smoothelin family of smooth muscle-specific proteins. In contrast to the smoothelins, SMTNL1 does not associate with F-actin in vitro, and its specific role in smooth muscle remains unclear. In addition, the biological function of the C-terminal CH-domains found in the smoothelin proteins is also poorly understood. In this work, we have therefore determined the solution structure of the CH-domain of mouse SMTNL1 (SMTNL1-CH; residues 346-459). The secondary structure and the overall fold for the C-terminal type-2 CH-domain is very similar to that of other CH-domains. However, two clusters of basic residues form a unique surface structure that is characteristic of SMTNL1-CH. Moreover, the protein has an extended C-terminal alpha-helix, which contains a calmodulin (CaM)-binding IQ-motif, that is also a distinct feature of the smoothelins. We have characterized the binding of apo-CaM to SMTNL1-CH through its IQ-motif by isothermal titration calorimetry and NMR chemical shift perturbation studies. In addition, we have used the HADDOCK protein-protein docking approach to construct a model for the complex of apo-CaM and SMTNL1-CH. The model revealed a close interaction of SMTNL1-CH with the two Ca(2+) binding loop regions of the C-terminal domain of apo-CaM; this mode of apo-CaM binding is distinct from previously reported interactions of apo-CaM with IQ-motifs. Finally, we comment on the putative role of the CH-domain in the biological function of SMTNL1.
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Affiliation(s)
- Hiroaki Ishida
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
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Malgaroli A, Malinow R, Schulman H, Tsien RW. Persistent signalling and changes in presynaptic function in long-term potentiation. CIBA FOUNDATION SYMPOSIUM 2007; 164:176-91; discussion 192-6. [PMID: 1327679 DOI: 10.1002/9780470514207.ch12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Long-term potentiation (LTP) is an example of a persistent change in synaptic function in the mammalian brain, thought to be essential for learning and memory. At the synapse between hippocampal CA3 and CA1 neurons LTP is induced by a Ca2+ influx through glutamate receptors of the NMDA (N-methyl-D-aspartate) type (see Collingridge et al 1992, this volume). How does a rise in [Ca2+]i lead to enhancement of synaptic function? We have tested the popular hypothesis that Ca2+ acts via a Ca(2+)-dependent protein kinase. We found that long-lasting synaptic enhancement was prevented by prior intracellular injection of potent and selective inhibitory peptide blockers of either protein kinase C (PKC) or Ca2+/calmodulin-dependent protein kinase II (CaMKII), such as PKC(19-31) or CaMKII(273-302), but not by control peptides. Evidently, activity of both PKC and CaMKII is somehow necessary for the postsynaptic induction of LTP. To determine if these kinases are also involved in the expression of LTP, we impaled cells with microelectrodes containing protein kinase inhibitors after LTP had already been induced. Strikingly, established LTP was not suppressed by a combination of PKC and CaMKII blocking peptides, or by intracellular postsynaptic H-7. However, established LTP remained sensitive to bath application of H-7. Thus, the persistent signal may be a persistent kinase, but if so, the kinase cannot be accessed within the postsynaptic cell. Evidence for a presynaptic locus of expression comes from our studies of quantal synaptic transmission under whole-cell voltage clamp. We find changes in synaptic variability expected to result from enhanced presynaptic transmitter release, but little or no increase in quantal size. Furthermore, miniature synaptic currents in hippocampal cultures are increased in frequency but not amplitude as a result of a glutamate-driven postsynaptic induction. The combination of postsynaptic induction and presynaptic expression necessitates a retrograde signal from the postsynaptic cell to the presynaptic terminal.
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Affiliation(s)
- A Malgaroli
- Department of Molecular and Cellular Physiology, Stanford University Medical Center, CA 94305-5425
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Zakharov VV, Mosevitsky MI. M-calpain-mediated cleavage of GAP-43 near Ser41 is negatively regulated by protein kinase C, calmodulin and calpain-inhibiting fragment GAP-43-3. J Neurochem 2007; 101:1539-51. [PMID: 17326767 DOI: 10.1111/j.1471-4159.2007.04452.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Neuronal protein GAP-43 performs multiple functions in axon guidance, synaptic plasticity and regulation of neuronal death and survival. However, the molecular mechanisms of its action in these processes are poorly understood. We have shown that in axon terminals GAP-43 is a substrate for calcium-activated cysteine protease m-calpain, which participates in repulsion of axonal growth cones and induction of neuronal death. In pre-synaptic terminals in vivo, in synaptosomes, and in vitro, m-calpain cleaved GAP-43 in a small region near Ser41, on either side of this residue. In contrast, micro-calpain cleaved GAP-43 in vitro at several other sites, besides Ser41. Phosphorylation of Ser41 by protein kinase C or GAP-43 binding to calmodulin strongly suppressed GAP-43 proteolysis by m-calpain. A GAP-43 fragment, lacking about forty N-terminal residues (named GAP-43-3), was produced by m-calpain-mediated cleavage of GAP-43 and inhibited m-calpain, but not micro-calpain. This fragment prevented complete cleavage of intact GAP-43 by m-calpain as a negative feedback. GAP-43-3 also blocked m-calpain activity against casein, a model calpain substrate. This implies that GAP-43-3, which is present in axon terminals in high amount, can play important role in regulation of m-calpain activity in neurons. We suggest that GAP-43-3 and another (N-terminal) GAP-43 fragment produced by m-calpain participate in modulation of neuronal response to repulsive and apoptotic signals.
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Affiliation(s)
- Vladislav V Zakharov
- Division of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute of Russian Academy of Sciences, Gatchina, Leningrad District, Russia.
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Dickerson JB, Morgan MA, Mishra A, Slaughter CA, Morgan JI, Zheng J. The influence of phosphorylation on the activity and structure of the neuronal IQ motif protein, PEP-19. Brain Res 2006; 1092:16-27. [PMID: 16740252 DOI: 10.1016/j.brainres.2006.03.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2006] [Revised: 03/02/2006] [Accepted: 03/06/2006] [Indexed: 11/24/2022]
Abstract
PEP-19 is a 7.6 kDa neuronally expressed polypeptide that contains a single calmodulin-binding IQ motif. The calmodulin-binding activity of several neuronal IQ motif proteins is regulated by phosphorylation of a conserved serine. We propose that the serine residue within the IQ motif of PEP-19 is phosphorylated, and that phosphorylation modifies the activity of PEP-19. Camstatin, a functionally active 25-residue fragment of PEP-19's IQ motif, binds calmodulin and inhibits neuronal nitric oxide synthase. A truncated camstatin-in which the IQ motif serine is the only phosphorylatable residue-was screened against 42 different kinases. Truncated camstatin is selectively phosphorylated by four isoforms of protein kinase C. Furthermore, treatment of full-length PEP-19 with PKCgamma catalyzes phosphorylation of the same serine residue. Fluorescent anisotropy shows that phosphorylation of camstatin inhibits its binding to calmodulin. NMR solution structures indicate that both camstatin and phospho-camstatin exist in similar dynamic turn-like conformations. This suggests that camstatin's greater affinity for calmodulin is due not to a change in the conformation of the phospho-peptide, but rather, to a disruption of hydrophobic interactions between phospho-camstatin and calmodulin caused by the presence of the hydrophilic phosphate group. The H(alpha) chemical shifts and the circular dichroism spectra of the camstatins are consistent with those of "nascent helices". We submit that PEP-19 is a PKC substrate, and that the phosphorylation state of PEP-19 may play a role in the modulation of calmodulin-dependent signaling.
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Affiliation(s)
- J Bradley Dickerson
- Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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Zakharov VV, Bogdanova MN, Mosevitsky MI. Specific Proteolysis of Neuronal Protein GAP-43 by Calpain: Characterization, Regulation, and Physiological Role. BIOCHEMISTRY (MOSCOW) 2005; 70:897-907. [PMID: 16212546 DOI: 10.1007/s10541-005-0200-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The mechanism of specific proteolysis of the neuronal protein GAP-43 in axonal terminals has been investigated. In synaptic terminals in vivo and in synaptosomes in vitro GAP-43 is cleaved only at the single peptide bond formed by Ser41; this is within the main effector domain of GAP-43. Proteolysis at this site involves the cysteine calcium-dependent neutral protease calpain. The following experimental evidences support this conclusion: 1) calcium-dependent proteolysis of GAP-43 in synaptosomes is insensitive to selective inhibitor of micro-calpain (PD151746), but it is completely blocked by micro- and m-calpain inhibitor PD150606; 2) GAP-43 proteolysis in the calcium ionophore A23187-treated synaptosomes is activated by millimolar concentration of calcium ions; 3) the pattern of fragmentation of purified GAP-43 by m-calpain (but not by micro-calpain) is identical to that observed in synaptic terminals in vivo. GAP-43 phosphorylated at Ser41 by protein kinase C (PKC) is resistant to the cleavage by calpain. In addition, calmodulin binding to GAP-43 decreases the rate of calpain-mediated GAP-43 proteolysis. Our results indicate that m-calpain-mediated GAP-43 proteolysis regulated by PKC and calmodulin is of physiological relevance, particularly in axonal growth cone guidance. We suggest that the function of the N-terminal fragment of GAP-43 (residues 1-40) formed during cleavage by m-calpain consists in activation of neuronal heterotrimeric GTP-binding protein G(o); this results in growth cone turning in response to repulsive signals.
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Affiliation(s)
- V V Zakharov
- Molecular and Radiation Biophysics Division, Petersburg Nuclear Physics Institute, Russian Academy of Sciences, Gatchina, Leningrad Region, 188300, Russia.
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De Moliner KL, Wolfson ML, Perrone Bizzozero N, Adamo AM. Growth-associated protein-43 is degraded via the ubiquitin-proteasome system. J Neurosci Res 2005; 79:652-60. [PMID: 15668958 DOI: 10.1002/jnr.20388] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Growth-associated protein-43 (GAP-43) is a phosphoprotein whose expression in neurons is related to the initial establishment and remodeling of neural connections. GAP-43 gene expression is known to be regulated at both the transcriptional and the postranscriptional levels. However, very little is known about the cellular mechanism involved in the degradation of this protein. Ubiquitin (Ub) is well known for its role in targeting cytoplasmic proteins for degradation by the 26S proteasome. The ubiquitin-proteasome system (UPS) consists of a conserved cascade of three enzymatic components that attach Ub covalently to various substrates and control the degradation of protein involved in several important cellular processes. In this study, we investigated the degradation of GAP-43 in transfected NIH 3T3 cells and neuronal cultures. We found that the proteasome inhibitors, lactacystin and MG132 increased the cellular GAP-43 level, leading to the accumulation of polyubiquitinated forms of this protein in transfected cells and that the Ub-proteasome pathway is also involved in the turnover of this protein in neurons. We conclude based on our findings that GAP-43 is a substrate of the UPS.
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Affiliation(s)
- K L De Moliner
- Departamento de Química Biológica, IQUIFIB, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
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34
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Mosevitsky MI. Nerve Ending “Signal” Proteins GAP‐43, MARCKS, and BASP1. INTERNATIONAL REVIEW OF CYTOLOGY 2005; 245:245-325. [PMID: 16125549 DOI: 10.1016/s0074-7696(05)45007-x] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Mechanisms of growth cone pathfinding in the course of neuronal net formation as well as mechanisms of learning and memory have been under intense investigation for the past 20 years, but many aspects of these phenomena remain unresolved and even mysterious. "Signal" proteins accumulated mainly in the axon endings (growth cones and the presynaptic area of synapses) participate in the main brain processes. These proteins are similar in several essential structural and functional properties. The most prominent similarities are N-terminal fatty acylation and the presence of an "effector domain" (ED) that dynamically binds to the plasma membrane, to calmodulin, and to actin fibrils. Reversible phosphorylation of ED by protein kinase C modulates these interactions. However, together with similarities, there are significant differences among the proteins, such as different conditions (Ca2+ contents) for calmodulin binding and different modes of interaction with the actin cytoskeleton. In light of these facts, we consider GAP-43, MARCKS, and BASP1 both separately and in conjunction. Special attention is devoted to a discussion of apparent inconsistencies in results and opinions of different authors concerning specific questions about the structure of proteins and their interactions.
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Affiliation(s)
- Mark I Mosevitsky
- Division of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute, Russian Academy of Sciences, 188300 Gatchina Leningrad District, Russian Federation
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35
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Denny JB. Growth-associated protein of 43 kDa (GAP-43) is cleaved nonprocessively by the 20S proteasome. ACTA ACUST UNITED AC 2004; 271:2480-93. [PMID: 15182364 DOI: 10.1111/j.1432-1033.2004.04179.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Purified, nonubiquitinated growth-associated protein of 43 kDa (GAP-43) was attacked by purified reticulocyte 20S proteasome but not by the 26S proteasome. Cleavage yielded 12 N-terminally labelled GAP-43 fragments that could be resolved by SDS/PAGE. Inhibitor experiments suggested that proteasome beta1 activity yielded the resolved bands and that proteasomebeta5 activity generated nonresolvable fragments. Processive degradation, yielding only nonresolvable fragments, therefore did not occur. Most of the resolved fragments co-migrated with fragments formed in the reticulocyte lysate translation mixture used for GAP-43 synthesis, which suggested that the fragments were also produced in the translation mixture by the endogenous reticulocyte lysate proteasome. Consistent with this idea, the addition of proteasome inhibitors to translation mixtures blocked fragment production. Ubiquitinated GAP-43 appeared to be the source of the fragments in the presence of ATP, and nonubiquitinated GAP-43 the source in the absence of ATP. The results therefore suggest that the lack of processing seen with the 20S proteasome is not an artefact arising from the way in which the 20S proteasome was purified. In one purification protocol, the GAP-43 fragments formed in translation mixtures co-purified with full-length GAP-43. These fragments were digested to nonresolvable products upon addition of purified 20S proteasome. Addition of calmodulin or G-actin blocked the consumption of both full-length GAP-43 and the co-purified GAP-43 fragments. This showed that the resolved fragments can re-enter the proteasome and be cleaved to nonresolvable products, indicating that the lack of processivity is not a result of their resistance to further proteasome attack. The difficult step therefore appears to be the transfer of the large fragments within the proteasome from the beta1 to the beta5 activity for further attack.
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Affiliation(s)
- John B Denny
- Department of Ophthalmology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
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36
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Wong MX, Harbour SN, Wee JL, Lau LM, Andrews RK, Jackson DE. Proteolytic cleavage of platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) is regulated by a calmodulin-binding motif. FEBS Lett 2004; 568:70-8. [PMID: 15196923 DOI: 10.1016/j.febslet.2004.04.094] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2004] [Revised: 04/25/2004] [Accepted: 04/30/2004] [Indexed: 01/23/2023]
Abstract
Homophilic engagement of platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) induces 'outside-in' signal transduction that results in phosphorylation events and recruitment and activation of signalling molecules. The formation of signalling scaffolds with PECAM-1 are important signalling events that modulate platelet secretion, aggregation and platelet thrombus formation. In this study, we describe a novel interaction between PECAM-1 and cytosolic calmodulin (CaM) in platelets. Reciprocal co-immunoprecipitation studies revealed that cytosolic CaM is constitutively associated with PECAM-1 in resting, thrombin activated and aggregated human platelets. Our studies demonstrate that CaM directly interacts with a PECAM-1 peptide (594-604) C595A containing the sequences (594)KAFYLRKAKAK(604). This CaM:PECAM-1 interaction has a threefold higher affinity than CaM:GPVI interaction. It is potentiated by the addition of calcium ions, and dissociated by the CaM inhibitor, trifluoperazine. Treatment of platelets with CaM inhibitors triggers cleavage of PECAM-1 in a time- and dose-dependent manner. Furthermore, this membrane proximal portion of PECAM-1 is conserved across mammalian species and the helical representation of basic/hydrophobic residues reveals a charge distribution analogous to other CaM-binding motifs in other proteins. Taken together, these results suggest that this highly charged cluster of amino acids in the PECAM-1 cytoplasmic domain directly interacts with CaM and this novel interaction appears to regulate cleavage of PECAM-1.
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Affiliation(s)
- Mae-Xhum Wong
- Kronheimer Building, Austin Research Institute, Austin Hospital, Heidelberg, Vic., Australia
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37
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Li Q, Stuenkel EL. Calcium negatively modulates calmodulin interaction with IQGAP1. Biochem Biophys Res Commun 2004; 317:787-95. [PMID: 15081409 DOI: 10.1016/j.bbrc.2004.03.119] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2004] [Indexed: 10/26/2022]
Abstract
IQGAP1 regulates cytoskeletal dynamics through interactions with the Rho family GTPases Rac1 and Cdc42, F-actin, and beta-catenin. Calmodulin interaction with IQ motifs of IQGAP1 negatively influences these IQGAP1 interactions. Although, calmodulin interacts with IQGAP1 in the absence of Ca(2+) and was suggested to exhibit reduced binding when Ca(2+) bound, recent reports show substantially greater binding when Ca(2+) is present. Binding evaluations have primarily relied on IQGAP1 interaction with calmodulin conjugated to Sepharose 4B. In this study we evaluated the Ca(2+)-dependence of calmodulin interaction with native IQGAP1 using a series of independent biochemical approaches. We found the apparent binding of calmodulin to IQGAP1 was Ca(2+)-independent, being between 5- and 20-fold greater in the absence than in the presence of Ca(2+). In addition, calmodulin interaction with IQGAP1 was negatively regulated by buffer [Ca(2+)] (IC(50)=3.4x10(-7)M). Regulation was specific to Ca(2+), as Ba(2+) was approximately 400-fold less effective than Ca(2+) at modulating the interaction. Moreover, testing of calmodulin mutants demonstrated that apocalmodulin tightly binds IQGAP1 and that the N- and C-terminal pair of EF hands are important for Ca(2+) sensitivity. These data indicate that calmodulin may disassemble from IQGAP1 to facilitate IQGAP1 interaction with effectors of cytoskeletal reorganization during conditions of cell activation that promote increased cytosolic [Ca(2+)].
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Affiliation(s)
- Quanwen Li
- Department of Molecular and Integrative Physiology, 7807 Medical Sciences II Bldg., The University of Michigan, Ann Arbor, MI 48109-0622, USA
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38
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Casoli T, Stefano GD, Fattoretti P, Solazzi M, Delfino A, Biagini G, Bertoni-Freddari C. GAP-43 mRNA detection by in situ hybridization, direct and indirect in situ RT-PCR in hippocampal and cerebellar tissue sections of adult rat brain. Micron 2004; 34:415-22. [PMID: 14680928 DOI: 10.1016/s0968-4328(03)00038-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2003] [Indexed: 10/27/2022]
Abstract
The growth-associated protein GAP-43 is a presynaptic membrane phosphoprotein that is expressed at high levels during development and axonal growth. To evaluate the cellular distribution of GAP-43 mRNA in the hippocampus and cerebellum of adult rats we applied in situ hybridization (ISH) as well as direct and indirect in situ RT-PCR using biotin as a reporter molecule. ISH resulted in a positive signal in most cerebellar granular cells and in 30% of hippocampal CA3 neurons. Direct in situ RT-PCR yielded cells with strong signals in every region investigated, with elevated background levels most likely related to incorporation of labeled nucleotides into non-specific amplicons through internal priming and DNA repair activity. Indirect in situ RT-PCR turned out to be the best approach for detecting GAP-43 mRNA positive cells. Cerebellar cells exhibiting a positive signal for GAP-43 mRNA were of the granular cell type (98%). Hippocampal neurons with a positive reaction for GAP-43 mRNA included all the neuron groups analyzed, namely CA1 (99%) and CA3 pyramidal cells (94%) and dentate gyrus granule cells (92%). Dentate gyrus granule cells have not tested positive for GAP-43 mRNA detection by molecular morphology analysis. These data show that in normal rats GAP-43 mRNA is present in different cell populations of hippocampal formation, supporting the role of this protein in the ongoing processes of synaptic plasticity.
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Affiliation(s)
- Tiziana Casoli
- Neurobiology of Aging Center, N. Masera INRCA Research Department, Via Birarelli 8, Ancona 60121, Italy.
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39
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Llovera M, de Pablo Y, Egea J, Encinas M, Peiró S, Martín-Zanca D, Rocamora N, Comella JX. Trk is a calmodulin-binding protein: implications for receptor processing. J Neurochem 2003; 88:422-33. [PMID: 14690530 DOI: 10.1046/j.1471-4159.2003.02178.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The tyrosine kinase receptors for the neurotrophins (Trk) are a family of transmembrane receptors that regulate the differentiation and survival of different neuronal populations. Neurotrophin binding to Trk leads to the activation of several signalling pathways including a rapid, but moderate, increase in intracellular calcium levels. We have previously described the role of calcium and its sensor protein, calmodulin, in Trk-activated intracellular pathways. Here we demonstrate that calmodulin is able to precipitate TrkA from PC12 cell lysates. Using recombinant GST-fusion proteins containing the complete intracellular domain of TrkA, or fragments of this region, we show that calmodulin binds directly to the C-terminal domain of TrkA in a Ca2+-dependent manner. We have also co-immunoprecipitated endogenous Trk and calmodulin in primary cultures of cortical neurones. Moreover, we provide evidence that calmodulin is involved in the regulation of TrkA processing in PC12 cells. Calmodulin inhibition results in the generation of a TrkA-derived p41 fragment from the cytosolic portion of the protein. This fragment is autophosphorylated in tyrosines and can recruit PLCgamma and Shc adaptor proteins. These results suggest that calmodulin binding to Trk may be important for the regulation of Trk intracellular localization and cleavage.
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Affiliation(s)
- Marta Llovera
- Grup de Neurobiologia Molecular, Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina, Universitat de Lleida, Lleida, Spain
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40
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Matsubara M, Titani K, Taniguchi H, Hayashi N. Direct Involvement of Protein Myristoylation in Myristoylated Alanine-rich C Kinase Substrate (MARCKS)-Calmodulin Interaction. J Biol Chem 2003; 278:48898-902. [PMID: 14506265 DOI: 10.1074/jbc.m305488200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
MARCKS, a major in vivo substrate of protein kinase C, interacts with plasma membranes in a phosphorylation-, myristoylation-, and calmodulin-dependent manner. Although we have previously observed that myristoylated and non-myristoylated MARCKS proteins behave differently during calmodulin-agarose chromatography, the role of protein myristoylation in the MARCKS-calmodulin interaction remained to be elucidated. Here we demonstrate that the myristoyl moiety together with the N-terminal protein domain is directly involved in the MARCKS-calmodulin interaction. Both myristoylated and non-myristoylated recombinant MARCKS bound to calmodulin-agarose at low ionic strengths, but only the former retained the affinity at high ionic strengths. A quantitative analysis obtained with dansyl (5-dimethylaminonaphthalene-1-sulfonyl)-calmodulin showed that myristoylated MARCKS has an affinity higher than the non-myristoylated protein. Furthermore, a synthetic peptide based on the N-terminal sequence was found to bind calmodulin only when it was myristoylated. Only the N-terminal peptide but not the canonical calmodulin-binding domain showed the ionic strength-independent calmodulin binding. A mutation study suggested that the importance of the positive charge in the N-terminal protein domain in the binding.
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Affiliation(s)
- Mamoru Matsubara
- Division of Biomedical Polymer Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan
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41
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Putkey JA, Kleerekoper Q, Gaertner TR, Waxham MN. A new role for IQ motif proteins in regulating calmodulin function. J Biol Chem 2003; 278:49667-70. [PMID: 14551202 DOI: 10.1074/jbc.c300372200] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
IQ motifs are found in diverse families of calmodulin (CaM)-binding proteins. Some of these, like PEP-19 and RC3, are highly abundant in neuronal tissues, but being devoid of catalytic activity, their biological roles are not understood. We hypothesized that these IQ motif proteins might have unique effects on the Ca2+ binding properties of CaM, since they bind to CaM in the presence or absence of Ca2+. Here we show that PEP-19 accelerates by 40 to 50-fold both the slow association and dissociation of Ca2+ from the C-domain of free CaM, and we identify the sites of interaction between CaM and PEP-19 using NMR. Importantly, we demonstrate that PEP-19 can also increase the rate of dissociation of Ca2+ from CaM when bound to intact CaM-dependent protein kinase II. Thus, PEP-19, and presumably similar members of the IQ family of proteins, has the potential to alter the Ca2+-binding dynamics of free CaM and CaM that is bound to other target proteins. Since Ca2+ binding to the C-domain of CaM is the rate-limiting step for activation of CaM-dependent enzymes, the data reveal a new concept of importance in understanding the temporal dynamics of Ca2+-dependent cell signaling.
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Affiliation(s)
- John A Putkey
- Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston, Texas 77030, USA.
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42
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Mori M, Konno T, Morii T, Nagayama K, Imoto K. Regulatory interaction of sodium channel IQ-motif with calmodulin C-terminal lobe. Biochem Biophys Res Commun 2003; 307:290-6. [PMID: 12859953 DOI: 10.1016/s0006-291x(03)01183-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
An increasing number of ion channels have been found to be regulated by the direct binding of calmodulin (CaM), but its structural features are mostly unknown. Previously, we identified the Ca(2+)-dependent and -independent interactions of CaM to the voltage-gated sodium channel via an IQ-motif sequence. In this study we used the trypsin-digested CaM fragments (TR(1)C and TR(2)C) to analyze the binding of Ca(2+)-CaM or Ca(2+)-free (apo) CaM with a sodium channel-derived IQ-motif peptide (NaIQ). Circular dichroic spectra showed that NaIQ peptide enhanced alpha-helicity of the CaM C-terminal lobe, but not that of the CaM N-terminal lobe in the absence of Ca(2+), whereas NaIQ enhanced the alpha-helicity of both the N- and C-terminal lobes in the presence of Ca(2+). Furthermore, the competitive binding experiment demonstrated that Ca(2+)-dependent CaM binding of target peptides (MLCKp or melittin) with CaM was markedly suppressed by NaIQ. The results suggest that IQ-motif sequences contribute to prevent target proteins from activation at low Ca(2+) concentrations and may explain a regulatory mechanism why highly Ca(2+)-sensitive target proteins are not activated in the cytoplasm.
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Affiliation(s)
- Masayuki Mori
- Department of Information Physiology, National Institute for Physiological Sciences, Okazaki, Japan
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43
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Li Z, Sacks DB. Elucidation of the interaction of calmodulin with the IQ motifs of IQGAP1. J Biol Chem 2003; 278:4347-52. [PMID: 12446675 DOI: 10.1074/jbc.m208579200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Calmodulin regulates the function of numerous proteins by binding to short regions on the target molecule. IQ motifs, which are found in over 100 human proteins, appear in tandem repeats and bind calmodulin in the absence of Ca(2+). One of these IQ-containing proteins, IQGAP1, interacts with several targets, including Cdc42, beta-catenin, E-cadherin, and actin, in a calmodulin-regulated manner. To elucidate the molecular mechanism by which apocalmodulin and Ca(2+)/calmodulin differentially regulate IQGAP1, a series of constructs of IQGAP1 with selected point mutations of the four tandem IQ motifs were generated. Mutating the basic charged arginine residues in all four IQ motifs abrogated binding of IQGAP1 to apocalmodulin, but had no effect on its interaction with Ca(2+)/calmodulin. Analysis of IQGAP1 constructs with point mutations in single, double, or triple IQ motifs revealed that apocalmodulin bound only to IQ3 and IQ4. By contrast to the arginine mutant constructs, mutation of selected hydrophobic residues in the IQ motifs produced an IQGAP1 protein incapable of binding either apocalmodulin or Ca(2+)/calmodulin. These results, which differ from the conventional model of Ca(2+)-independent binding of calmodulin to IQ motifs, provide insight into the complexity of the molecular interactions between calmodulin and IQ motifs.
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Affiliation(s)
- Zhigang Li
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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44
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Martin SR, Bayley PM. Regulatory implications of a novel mode of interaction of calmodulin with a double IQ-motif target sequence from murine dilute myosin V. Protein Sci 2002; 11:2909-23. [PMID: 12441389 PMCID: PMC2373755 DOI: 10.1110/ps.0210402] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2002] [Revised: 07/17/2002] [Accepted: 09/04/2002] [Indexed: 10/27/2022]
Abstract
Apo-Calmodulin acts as the light chain for unconventional myosin V, and treatment with Ca(2+) can cause dissociation of calmodulin from the 6IQ region of the myosin heavy chain. The effects of Ca(2+) on the stoichiometry and affinity of interactions of calmodulin and its two domains with two myosin-V peptides (IQ3 and IQ4) have therefore been quantified in vitro, using fluorescence and near- and far-UV CD. The results with separate domains show their differential affinity in interactions with the IQ motif, with the apo-N domain interacting surprisingly weakly. Contrary to expectations, the effect of Ca(2+) on the interactions of either peptide with either isolated domain is to increase affinity, reducing the K(d) at physiological ionic strengths by >200-fold to approximately 75 nM for the N domain, and approximately 10-fold to approximately 15 nM for the C domain. Under suitable conditions, intact (holo- or apo-) calmodulin can bind up to two IQ-target sequences. Interactions of apo- and holo-calmodulin with the double-length, concatenated sequence (IQ34) can result in complex stoichiometries. Strikingly, holo-calmodulin forms a high-affinity 1:1 complex with IQ34 in a novel mode of interaction, as a "bridged" structure wherein two calmodulin domains interact with adjacent IQ motifs. This apparently imposes a steric requirement for the alpha-helical target sequence to be discontinuous, possibly in the central region, and a model structure is illustrated. Such a mode of interaction could account for the Ca(2+)-dependent regulation of myosin V in vitro motility, by changing the structure of the regulatory complex, and paradoxically causing calmodulin dissociation through a change in stoichiometry, rather than a Ca(2+)-dependent reduction in affinity.
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Affiliation(s)
- Stephen R Martin
- Division of Physical Biochemistry, National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
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45
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Liang X, Lu Y, Neubert TA, Resh MD. Mass spectrometric analysis of GAP-43/neuromodulin reveals the presence of a variety of fatty acylated species. J Biol Chem 2002; 277:33032-40. [PMID: 12105219 DOI: 10.1074/jbc.m204607200] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
GAP-43 (neuromodulin) is a protein kinase C substrate that is abundant in developing and regenerating neurons. Thioester-linked palmitoylation at two cysteines near the GAP-43 N terminus has been implicated in directing membrane binding. Here, we use mass spectrometry to examine the stoichiometry of palmitoylation and the molecular identity of the fatty acid(s) attached to GAP-43 in vivo. GAP-43 expressed in either PC12 or COS-1 cells was acetylated at the N-terminal methionine. Approximately 35% of the N-terminal GAP-43 peptides were also modified by palmitate and/or stearate on Cys residues. Interestingly, a variety of acylated species was detected, in which one of the Cys residues was acylated by either palmitate or stearate, or both Cys residues were acylated by palmitates or stearates or a combination of palmitate and stearate. Depalmitoylation of membrane-bound GAP-43 did not release the protein from the membrane, implying that additional forces function to maintain membrane binding. Indeed, mutation of four basic residues within the N-terminal domain of GAP-43 dramatically reduced membrane localization of GAP-43 without affecting palmitoylation. These data reveal the heterogeneous nature of S-acylation in vivo and illustrate the power of mass spectrometry for identification of key regulatory protein modifications.
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Affiliation(s)
- Xiquan Liang
- Cell Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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46
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Morton AJ, Buss TN. Accelerated Differentiation in Response to Retinoic Acid After Retrovirally Mediated Gene Transfer of GAP-43 into Mouse Neuroblastoma Cells. Eur J Neurosci 2002; 4:910-916. [PMID: 12106426 DOI: 10.1111/j.1460-9568.1992.tb00117.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although substantial evidence exists for the involvement of growth-associated protein-43 (GAP-43) in neuronal development and regeneration, the precise role of this protein in neurite outgrowth is currently debated. To investigate the role of GAP-43 in the initiation of neurite outgrowth, we transfected a full-length cDNA coding for GAP-43 into a mouse neuroblastoma cell line (Neuro-2a) which can be differentiated to a neuronal phenotype using retinoic acid (RA). We show that the consequent overexpression of GAP-43 results in a change in the basic morphology of these cells, but is not in itself sufficient to induce the extension of neurites. However, overexpression of GAP-43 results in a marked acceleration of neurite formation in response to RA. We propose that while GAP-43 does not trigger the initiation of neurite extension, its expression is rate-limiting for neurite outgrowth in response to differentiation agents such as RA.
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Affiliation(s)
- A. Jennifer Morton
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QJ, UK
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47
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Sobiesiak-Mirska J, Nałecz KA. Palmitoylcarnitine modulates interaction protein kinase C delta-GAP-43. Biochem Biophys Res Commun 2002; 294:823-8. [PMID: 12061781 DOI: 10.1016/s0006-291x(02)00559-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Palmitoylcarnitine, reported previously to promote neuronal differentiation, was observed to affect distribution of protein kinase C (PKC) isoforms in neuroblastoma NB-2a cells, leading to retardation in cytoplasm of high molecular weight species of PKCbeta and delta. Growth cone protein-GAP-43, a PKC substrate, was co-immunoprecipitated with all the conventional and novel PKCs: palmitoylcarnitine, however, decreased its amount exclusively in the complex with PKCdelta. Administration of palmitoylcarnitine, although did not change the subcellular distribution of GAP-43, decreased its phosphorylation, which could regulate other signal transduction pathways (calmodulin and G(0)-dependent).
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Hulo S, Alberi S, Laux T, Muller D, Caroni P. A point mutant of GAP-43 induces enhanced short-term and long-term hippocampal plasticity. Eur J Neurosci 2002; 15:1976-82. [PMID: 12099903 DOI: 10.1046/j.1460-9568.2002.02026.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The growth-associated protein GAP-43 (or neuromodulin or B-50) plays a critical role during development in mechanisms of axonal growth and formation of synaptic networks. At later times, GAP-43 has also been implicated in the regulation of synaptic transmission and properties of plasticity such as long-term potentiation. In a molecular approach, we have analyzed transgenic mice overexpressing different mutated forms of GAP-43 or deficient in GAP-43 to investigate the role of the molecule in short-term and long-term plasticity. We report that overexpression of a mutated form of GAP-43 that mimics constitutively phosphorylated GAP-43 results in an enhancement of long-term potentiation in CA1 hippocampal slices. This effect is specific, because LTP was affected neither in transgenic mice overexpressing mutated forms of non-phosphorylatable GAP-43 nor in GAP-43 deficient mice. The increased LTP observed in transgenic mice expressing a constitutively phosphorylated GAP-43 was associated with an increased paired-pulse facilitation as well as an increased summation of responses during high frequency bursts. These results indicate that, while GAP-43 is not necessary for LTP induction, its phosphorylation may regulate presynaptic properties, thereby affecting synaptic plasticity and the induction of LTP.
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Affiliation(s)
- S Hulo
- Neuropharmacology, Centre Médical Universitaire, rue M. Servet 1, 1211 Geneva 4, Switzerland
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Mons N, Enderlin V, Jaffard R, Higueret P. Selective age-related changes in the PKC-sensitive, calmodulin-binding protein, neurogranin, in the mouse brain. J Neurochem 2001; 79:859-67. [PMID: 11723178 DOI: 10.1046/j.1471-4159.2001.00646.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Brain ageing is associated with a dysregulation of intracellular calcium (Ca(2+)) homeostasis which leads to deficits in Ca(2+)-dependent signalling pathways and altered neuronal functions. Given the crucial role of neurogranin/RC3 (Ng) in the post-synaptic regulation of Ca(2+) and calmodulin levels, age-dependent changes in the levels of Ng mRNA and protein expression were analysed in 3, 12, 24 and 31-month-old mouse brains. Ageing produced significant decreases in Ng mRNA expression in the dorsal hippocampal subfields, retrosplenial and primary motor cortices, whereas no reliable changes were seen in any other cortical regions examined. Western blot indicated that Ng protein expression was also down-regulated in the ageing mouse brain. Analysis of Ng immunoreactivity in both hippocampal CA1 and retrosplenial areas indicated that Ng protein in aged mice decreased predominantly in the dendritic segments of pyramidal neurones. These data suggest that age-related changes of post-synaptic Ng in selected brain areas, and particularly in hippocampus, may contribute to altered Ca(2+)/calmodulin-signalling pathways and to region-specific impairments of synaptic plasticity and cognitive decline.
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Affiliation(s)
- N Mons
- Laboratoire de Neurosciences Cognitives UMR CNRS 5106, Université de Bordeaux, Talence, France.
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Li J, Huang FL, Huang KP. Glutathiolation of proteins by glutathione disulfide S-oxide derived from S-nitrosoglutathione. Modifications of rat brain neurogranin/RC3 and neuromodulin/GAP-43. J Biol Chem 2001; 276:3098-105. [PMID: 11060308 DOI: 10.1074/jbc.m008260200] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
S-Nitrosoglutathione (GSNO) undergoes spontaneous degradation that generates several nitrogen-containing compounds and oxidized glutathione derivatives. We identified glutathione sulfonic acid, glutathione disulfide S-oxide (GS(O)SG), glutathione disulfide S-dioxide, and GSSG as the major decomposition products of GSNO. Each of these compounds and GSNO were tested for their efficacies to modify rat brain neurogranin/RC3 (Ng) and neuromodulin/GAP-43 (Nm). Among them, GS(O)SG was found to be the most potent in causing glutathiolation of both proteins; four glutathiones were incorporated into the four Cys residues of Ng, and two were incorporated into the two Cys residues of Nm. Ng and Nm are two in vivo substrates of protein kinase C; their phosphorylations by protein kinase C attenuate the binding affinities of both proteins for calmodulin. When compared with their respective unmodified forms, the glutathiolated Ng was a poorer substrate and glutathiolated Nm a better substrate for protein kinase C. Glutathiolation of these two proteins caused no change in their binding affinities for calmodulin. Treatment of [(35)S]cysteine-labeled rat brain slices with xanthine/xanthine oxidase or a combination of xanthine/xanthine oxidase with sodium nitroprusside resulted in an increase in cellular level of GS(O)SG. These treatments, as well as those by other oxidants, all resulted in an increase in thiolation of proteins; among them, thiolation of Ng was positively identified by immunoprecipitation. These results show that GS(O)SG is one of the most potent glutathiolating agents generated upon oxidative stress.
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Affiliation(s)
- J Li
- Section on Metabolic Regulation, Endocrinology and Reproduction Research Branch, NICHD, National Institutes of Health, Bethesda, Maryland 20892-4510, USA
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