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Ghoweba RE, Khowailed AA, Aboulhoda BE, Rashed LA, Selmy A. Synergistic role of resveratrol and exercise training in management of diabetic neuropathy and myopathy via SIRT1/NGF/GAP43 linkage. Tissue Cell 2023; 81:102014. [PMID: 36621294 DOI: 10.1016/j.tice.2023.102014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/10/2022] [Accepted: 01/04/2023] [Indexed: 01/07/2023]
Abstract
AIMS Oxidative stress also plays an important role in the pathogenesis of diabetic neuropathy (DN). Both resveratrol (RES) and exercise (EX) have potent anti-oxidative benefits. Low levels of nerve growth factor (NGF) and SIRT1 (a member of sirtuin family) have been reported in patients with DN. The current study has been designed to investigate the role of serum NGF and SIRT1 on DN-induced hyperalgesia and motor incoordination and to evaluate the possible protective role of RES and/or EX. MAIN METHODS A total of 40 male adult albino rats divided into five groups; control, DN, DN + RES, DN + EX, and DN + RES and EX. DN was confirmed by sensorimotor disturbance and diminished nerve conduction velocity (NCV). NGF and SIRT1 levels were measured by western blot. Calcitonin gene-related peptide (CGRP) was measured by PCR. Myofibrillar degeneration and inflammation scores were revealed via H&E microscopic analysis of the gastrocnemius muscle. Immunohistochemical evaluation of caspase3 and TNF-α was performed in the lumber segment of spinal cord and gastrocnemius muscle sections. Ultrastructural evaluation of sciatic nerve axonal degeneration has also been assessed. KEY FINDINGS DN group showed decreased SIRT1 level, decreased NGF level and correlated with CGRP level and Na+/K+ ATPase. Treatment with RES and/or EX resulted in improvement of sensorimotor disturbance. DN characterized by reduced SOD level, whereas RES and/or EX could limit oxidative damage by up-regulation Bcl2, Akt and GAP-43 and down-regulation of caspase3 and TNF-α. In conclusion, increased level of SIRT1and NGF by incorporation of RES (natural supplementation) and EX (life style modification) could improve the neuroinflammatory state in DN.
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Affiliation(s)
| | | | - Basma Emad Aboulhoda
- Department of Anatomy and Embryology, Faculty of Medicine, Cairo University, Egypt.
| | - Laila Ahmed Rashed
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Cairo University, Egypt
| | - Asmaa Selmy
- Department of Physiology, Faculty of Medicine, Cairo University, Egypt
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2
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Chen T, Wang Y, Wang YH, Hang CH. The Mfn1-βIIPKC Interaction Regulates Mitochondrial Dysfunction via Sirt3 Following Experimental Subarachnoid Hemorrhage. Transl Stroke Res 2022; 13:845-857. [PMID: 35192161 DOI: 10.1007/s12975-022-00999-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 01/21/2022] [Accepted: 02/16/2022] [Indexed: 10/19/2022]
Abstract
Neuronal injury following subarachnoid hemorrhage (SAH) has been shown to be associated with mitochondrial dysfunction and oxidative stress. βIIPKC, a subtype of protein kinase C (PKC), accumulates on the mitochondrial outer membrane and phosphorylates mitofusin 1 (Mfn1) at serine 86. Here, we investigated the role of Mfn1-βIIPKC interaction in brain damage and neurological function in both in vivo and in vitro experimental SAH models. The expression of βIIPKC protein and the interaction of Mfn1-βIIPKC were found to be increased after OxyHb treatment in primary cultured cortical neurons and were also observed in the brain following SAH in rats. Treatment with the βIIPKC inhibitor βIIV5-3 or SAMβA, a peptide that selectively antagonizes Mfn1-βIIPKC association, significantly attenuated the OxyHb-induced neuronal injury and apoptosis. These protective effects were accompanied by inhibited mitochondrial dysfunction and preserved mitochondrial biogenesis. The results of western blot showed that βIIV5-3 or SAMβA markedly increased the expression of Sirt3 and enhanced the activities of its downstream mitochondrial antioxidant enzymes in OxyHb-treated neurons. Knockdown of Sirt3 via specific targeted small interfering RNA (siRNA) partially prevented the βIIV5-3- or SAMβA-induced protection and antioxidative effects. In addition, treatment with βIIV5-3 or SAMβA in vivo was found to obviously reduce brain edema, alleviate neuroinflammation, and preserve neurological function after experimental SAH in rats. In congruent with in vitro data, the protection induced by βIIV5-3 or SAMβA was reduced by Sirt3 knockdown in vivo. In summary, our present results showed that blocking Mfn1-βIIPKC interaction protects against brain damage and mitochondrial dysfunction via Sirt3 following experimental SAH.
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Affiliation(s)
- Tao Chen
- Department of Neurosurgery, Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210000, Jiangsu, China
- Department of Neurosurgery, The 904Th Hospital of PLA, Medical School of Anhui Medical University, Wuxi, 214044, Jiangsu, China
| | - Yue Wang
- Department of Neurosurgery, The 904Th Hospital of PLA, Medical School of Anhui Medical University, Wuxi, 214044, Jiangsu, China
| | - Yu-Hai Wang
- Department of Neurosurgery, The 904Th Hospital of PLA, Medical School of Anhui Medical University, Wuxi, 214044, Jiangsu, China.
| | - Chun-Hua Hang
- Department of Neurosurgery, Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210000, Jiangsu, China.
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3
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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: 70] [Impact Index Per Article: 17.5] [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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Erfani M, Ghazi Tabatabaei Z, Sadigh-Eteghad S, Farokhi-Sisakht F, Farajdokht F, Mahmoudi J, Karimi P, Nasrolahi A. Rosa canina L. methanolic extract prevents heat stress-induced memory dysfunction in rats. Exp Physiol 2019; 104:1544-1554. [PMID: 31297904 DOI: 10.1113/ep087535] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 07/09/2019] [Indexed: 12/17/2022]
Abstract
NEW FINDINGS What is the central question of this study? Heat stress has harmful effects on the brain structure and synaptic density via induction of oxidative stress and neuroinflammation, which result in neuronal damage in the hippocampus and thereby cognitive impairments. In this study, we investigate the effect of Rosa canina treatment on cognitive function in heat stress-exposed rats and its underlying mechanisms. What is the main finding and its importance? We show that R. canina improves cognitive deficits induced by heat stress by attenuation of oxidative stress and neuroinflammation and by upregulation of synaptic proteins in the hippocampus. ABSTRACT The aim of the study was to evaluate the effects of aqueous methanolic extract of Rosa canina (RC) dried fruits on oxidative stress, inflammation, synaptic degeneration and memory dysfunction induced by heat stress (HS) in rats. Sixty adult male Wistar rats were randomly divided into five groups as follows: the control group received normal saline (NS); the HS group was exposed to heat stress (43°C) for 15 min once a day for 2 weeks; and HS+R groups were exposed to heat stress and received one of three doses (250, 500 or 1000 mg kg-1 ) of RC methanolic extract for 2 weeks. A passive avoidance test and a Y-maze test were performed to assess learning and memory. The levels of reactive oxygen species were assessed. The serum cortisol concentration and hippocampal total antioxidant capacity, superoxide dismutase and glutathione peroxidase were also detected using spectrophotometry. The protein expressions of c-Fos, heat-shock protein-70, tumour necrosis factor-α, growth-associated protein 43, post-synaptic density-95 and synaptophysin were evaluated in the hippocampal tissue. The results showed that RC significantly improved cognitive dysfunction induced by HS, which was accompanied by downregulation of tumour necrosis factor-α and upregulation of growth-associated protein 43 and synaptophysin proteins in the hippocampus of HS-exposed rats. Furthermore, RC significantly attenuated serum cortisol concentrations and upregulated heat shock protein-70 and c-Fos in the hippocampus. In addition, the administration of RC attenuated reactive oxygen species levels and enhanced antioxidant defense in the hippocampus. These findings indicate that RC attenuated the deleterious effect of HS on cognition through its antioxidant properties and by enhancing synaptic function and plasticity.
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Affiliation(s)
- Marjan Erfani
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Higher Education Institute of Rab-Rashid, Tabriz, Iran
| | | | - Saeed Sadigh-Eteghad
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Fereshteh Farajdokht
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Javad Mahmoudi
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Pouran Karimi
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ava Nasrolahi
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Biochemistry and Molecular Medicine, School of Medicine, Ilam University of Medical Sciences, Ilam, Iran
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5
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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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Flamm AG, Żerko S, Zawadzka-Kazimierczuk A, Koźmiński W, Konrat R, Coudevylle N. 1H, 15N, 13C resonance assignment of human GAP-43. BIOMOLECULAR NMR ASSIGNMENTS 2016; 10:171-174. [PMID: 26748655 PMCID: PMC4788685 DOI: 10.1007/s12104-015-9660-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/28/2015] [Indexed: 05/31/2023]
Abstract
GAP-43 is a 25 kDa neuronal intrinsically disordered protein, highly abundant in the neuronal growth cone during development and regeneration. The exact molecular function(s) of GAP-43 remains unclear but it appears to be involved in growth cone guidance and actin cytoskeleton organization. Therefore, GAP-43 seems to play an important role in neurotransmitter vesicle fusion and recycling, long-term potentiation, spatial memory formation and learning. Here we report the nearly complete assignment of recombinant human GAP-43.
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Affiliation(s)
- Andrea Gabriele Flamm
- Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Szymon Żerko
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Anna Zawadzka-Kazimierczuk
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Wiktor Koźmiński
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Robert Konrat
- Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Nicolas Coudevylle
- Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria.
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7
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Kurzbach D, Kontaxis G, Coudevylle N, Konrat R. NMR Spectroscopic Studies of the Conformational Ensembles of Intrinsically Disordered Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 870:149-85. [PMID: 26387102 DOI: 10.1007/978-3-319-20164-1_5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Intrinsically disordered proteins (IDPs) are characterized by substantial conformational flexibility and thus not amenable to conventional structural biology techniques. Given their inherent structural flexibility NMR spectroscopy offers unique opportunities for structural and dynamic studies of IDPs. The past two decades have witnessed significant development of NMR spectroscopy that couples advances in spin physics and chemistry with a broad range of applications. This chapter will summarize key advances in NMR methodology. Despite the availability of efficient (multi-dimensional) NMR experiments for signal assignment of IDPs it is discussed that NMR of larger and more complex IDPs demands spectral simplification strategies capitalizing on specific isotope-labeling strategies. Prototypical applications of isotope labeling-strategies are described. Since IDP-ligand association and dissociation processes frequently occur on time scales that are amenable to NMR spectroscopy we describe in detail the application of CPMG relaxation dispersion techniques to studies of IDP protein binding. Finally, we demonstrate that the complementary usage of NMR and EPR data provide a more comprehensive picture about the conformational states of IDPs and can be employed to analyze the conformational ensembles of IDPs.
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Affiliation(s)
- Dennis Kurzbach
- Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Georg Kontaxis
- Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Nicolas Coudevylle
- Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Robert Konrat
- Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria.
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8
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Fredrich M, Zeber AC, Hildebrandt H, Illing RB. Differential molecular profiles of astrocytes in degeneration and re-innervation after sensory deafferentation of the adult rat cochlear nucleus. Eur J Neurosci 2013; 38:2041-56. [PMID: 23581580 DOI: 10.1111/ejn.12200] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 02/22/2013] [Accepted: 02/25/2013] [Indexed: 11/30/2022]
Abstract
Ablating the cochlea causes total sensory deafferentation of the cochlear nucleus. Over the first postoperative week, degeneration of the auditory nerve and its synaptic terminals in the cochlear nucleus temporally overlaps with its re-innervation by axon collaterals of medial olivocochlear neurons. At the same time, astrocytes increase in size and density. We investigated the time courses of the expression of ezrin, polysialic acid, matrix metalloprotease-9 and matrix metalloprotease-2 within these astrocytes during the first week following cochlear ablation. All four proteins are known to participate in degeneration, regeneration, or both, following injury of the central nervous system. In a next step, stereotaxic injections of kainic acid were made into the ventral nucleus of the trapezoid body prior to cochlear ablation to destroy the neurons that re-innervate the deafferented cochlear nucleus by axon collaterals developing growth-associated protein 43 immunoreactivity. This experimental design allowed us to distinguish between molecular processes associated with degeneration and those associated with re-innervation. Under these conditions, astrocytic growth and proliferation showed an unchanged deafferentation-induced pattern. Similarly, the distribution and amount of ezrin and matrix metalloprotease-9 in astrocytes after cochlear ablation developed in the same way as under cochlear ablation alone. In sharp contrast, the astrocytic expression of polysialic acid and matrix metalloprotease-2 normally invoked by cochlear ablation collapsed when re-innervation of the cochlear nucleus was inhibited by lesioning medial olivocochlear neurons with kainic acid. In conclusion, re-innervation, including axonal growth and synaptogenesis, seems to prompt astrocytes to recompose their molecular profile, paving the way for tissue reorganisation after nerve degeneration and loss of synaptic contacts.
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Affiliation(s)
- Michaela Fredrich
- Neurobiological Research Laboratory, Department of Otorhinolaryngology, University of Freiburg, Killianst 5, Freiburg 79106, Germany.
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Cheon SH, Koo HM. Spontaneous and Forced Exercise Promotes Cognitive Function and Expression of GAP-43 and NT-3 in the Hippocampus of Aged Rats. J Phys Ther Sci 2013. [DOI: 10.1589/jpts.25.321] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
| | - Hyun-Mo Koo
- Department of Physical Therapy, Kyungsung University: 309 Suyeong-ro, Daeyeon-dong, Nam-gu, Busan, Republic of Korea
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10
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Morita S, Miyata S. Synaptic localization of growth-associated protein 43 in cultured hippocampal neurons during synaptogenesis. Cell Biochem Funct 2012; 31:400-11. [PMID: 23055398 DOI: 10.1002/cbf.2914] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 09/11/2012] [Accepted: 09/12/2012] [Indexed: 11/07/2022]
Abstract
Growth-associated protein 43 (GAP-43), a novel axonal phosphoprotein, is originally identified as a growth-cone-specific protein of developing neurons in vitro. The expression of GAP-43 is also shown to be up-regulated concomitant with increased synaptic plasticity in the brains in vivo, but how GAP-43 is concerned with synaptic plasticity is not well understood. In the present study, therefore, we aimed to elucidate subcellular localization of GAP-43 as culture development of rat hippocampal neurons. Western blotting showed that the expression of GAP-43 in the cerebral and hippocampal tissues was prominently high at postnatal days 14 and 21 or the active period of synaptogenesis. Double-labelling immunohistochemistry with an axonal marker Tau revealed that the immunoreactivity of GAP-43 was seen throughout axons of cultured hippocampal neurons but stronger at axonal puncta of developing neurons than axonal processes. Double-labelling immunohistochemistry with presynaptic terminal markers of synapsin and synaptotagmin revealed that the immunoreactivity of GAP-43 was observed mostly at weak synapsin- and synaptotagmin-positive puncta rather than strong ones. The quantitative analysis of immunofluorescent intensity showed a clear inverse correlation between GAP-43 and either synapsin or synaptotagmin expression. These data indicate that GAP-43 is highly expressed at immature growing axonal terminals and its expression is decreased along with the maturation of synaptogenesis.
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Affiliation(s)
- Shoko Morita
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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11
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Role of the growth-associated protein GAP-43 in NCAM-mediated neurite outgrowth. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 663:169-82. [PMID: 20017022 DOI: 10.1007/978-1-4419-1170-4_11] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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12
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Jutapakdeegul N, Afadlal S, Polaboon N, Phansuwan‐Pujito P, Govitrapong P. Repeated restraint stress and corticosterone injections during late pregnancy alter GAP‐43 expression in the hippocampus and prefrontal cortex of rat pups. Int J Dev Neurosci 2009; 28:83-90. [DOI: 10.1016/j.ijdevneu.2009.09.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 09/01/2009] [Accepted: 09/15/2009] [Indexed: 11/26/2022] Open
Affiliation(s)
- Nuanchan Jutapakdeegul
- Neuro‐Behavioral Biology CenterInstitute of Molecular BiosciencesMahidol UniversityNakornpathom73170Thailand
| | - Szeifoul Afadlal
- Neuro‐Behavioral Biology CenterInstitute of Molecular BiosciencesMahidol UniversityNakornpathom73170Thailand
| | - Nongnuch Polaboon
- Faculty of Allied Health SciencesChristian UniversityNakornpathom73000Thailand
| | | | - Piyarat Govitrapong
- Neuro‐Behavioral Biology CenterInstitute of Molecular BiosciencesMahidol UniversityNakornpathom73170Thailand
- Center for NeuroscienceFaculty of ScienceMahidol UniversityBangkokThailand
- Department of Pharmacology, Faculty of ScienceMahidol UniversityBangkokThailand
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Asai H, Yokoyama S, Morita S, Maeda N, Miyata S. Functional difference of receptor-type protein tyrosine phosphatase zeta/beta isoforms in neurogenesis of hippocampal neurons. Neuroscience 2009; 164:1020-30. [PMID: 19751804 DOI: 10.1016/j.neuroscience.2009.09.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 08/19/2009] [Accepted: 09/04/2009] [Indexed: 01/01/2023]
Abstract
Receptor-type protein tyrosine phosphatase zeta/beta (RPTPzeta) is a transmembrane chondroitin sulfate proteoglycan (CSPG) and has been shown to play crucial roles in controlling axonal growth and neuronal migration. The RPTPzeta has two transmembranous isoforms, shorter receptor form of RPTPzeta (sRPTPzeta) and full-length receptor form of RPTPzeta (fRPTPzeta), but no studies have been reported about functional difference of these two isoforms. In the present study, therefore, we examined whether or not two RPTPzeta isoforms have different role in controlling dendritic morphology and synaptic number in cultured hippocampal neurons using the quantitative morphometrical analysis. Confocal microscopic observation showed that the immunoreactivity of RPTPzeta was observed throughout cells such as axons, growth cones, and dendrites at the early stages of neuronal culture, while it was seen predominantly on dendrites at the late stages. Western blotting analysis revealed that fRPTPzeta was mainly expressed at the early stages of culture and both RPTPzeta isoforms were expressed at late stages of culture. The overexpression of sRPTPzeta in hippocampal neurons increased the dendritic arborization without altering the average length of dendritic branches, whereas that of fRPTPzeta decreased the dendritic arborization and increased the average length of dendritic branches. The RNA interference of fRPTPzeta expression increased the dendritic arborization without altering the average length of dendritic branches. The overexpression of fRPTPzeta decreased the density of hippocampal dendritic synapses, but that of sRPTPzeta had no effects. Pleiotrophin, a ligand for RPTPzeta to interfere the phosphatase activity, increased the density of hippocampal dendritic synapses. Thus, the present study demonstrates that two transmembranous RPTPzeta isoforms have different functions for regulating dendritogenesis and synaptogenesis.
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Affiliation(s)
- H Asai
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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14
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Nguyen L, He Q, Meiri KF. Regulation of GAP-43 at serine 41 acts as a switch to modulate both intrinsic and extrinsic behaviors of growing neurons, via altered membrane distribution. Mol Cell Neurosci 2009; 41:62-73. [PMID: 19249369 PMCID: PMC2795319 DOI: 10.1016/j.mcn.2009.01.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Revised: 12/23/2008] [Accepted: 01/27/2009] [Indexed: 10/21/2022] Open
Abstract
GAP-43 is the major neuronal substrate of protein kinase C (PKC). Its phosphorylation status dictates the severity of pathfinding errors by GAP-43 (+/-) growth cones in vivo, as well as its modulation of actin dynamics in vitro. These experiments show that stably overexpressing cDNAs mutant at its single PKC phosphorylation site at serine41 in retinoic acid treated SH-Sy5Y neuroblastoma cells regulates intrinsic and extrinsic behaviors of growing neurons. Intrinsically, only Wt and pseudophosphorylated GAP-43Ser41Asp precipitated with F-actin and potentiated F-actin - regulated filopodia formation. GAP-43Ser41Asp inhibited neurite outgrowth whereas only unphosphorylatable GAP-43Ser41Ala precipitated neurotubulin, potentiated neurotubulin accumulation in neurites and increased outgrowth. When PI3-kinase was inhibited GAP-43Ser41Asp-mediated filopodia formation was inhibited whereas GAP-43Ser41Ala-mediated neurite extension was potentiated. Extrinsically, only Wt and GAP-43Ser41Asp potentiated both homotypic adhesion and neurite outgrowth on NCAM-expressing monolayers and promoted NCAM stability. With respect to the underlying mechanism, more F-actin and NCAM colocalized with Wt and GAP-43Ser41Asp in detergent resistant membranes (DRMs) isolated from live cells and GAP-43Ser41Asp-mediated functions were insensitive to cholesterol depletion. In contrast, GAP-43Ser41Ala-mediated functions were sensitive to cholesterol depletion. Neither GAP-43Ser41Asp nor GAP-43Ser41Ala was able to protect against growth cone collapse mediated by PIP2 inhibitors. The results show that modification of GAP-43 at its PKC phosphorylation site directs its distribution to different membrane microdomains that have distinct roles in the regulation of intrinsic and extrinsic behaviors in growing neurons.
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Affiliation(s)
- Lilly Nguyen
- Department of Anatomy and Cellular Biology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
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15
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Korshunova I, Mosevitsky M. Role of the Growth-associated Protein GAP-43 in NCAM-mediated Neurite Outgrowth. Neurochem Res 2008. [DOI: 10.1007/s11064-008-9800-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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Wang P, Jeng CJ, Chien CL, Wang SM. Signaling mechanisms of daidzein-induced axonal outgrowth in hippocampal neurons. Biochem Biophys Res Commun 2008; 366:393-400. [DOI: 10.1016/j.bbrc.2007.11.147] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Accepted: 11/22/2007] [Indexed: 11/24/2022]
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Einat H, Yuan P, Szabo ST, Dogra S, Manji HK. Protein kinase C inhibition by tamoxifen antagonizes manic-like behavior in rats: implications for the development of novel therapeutics for bipolar disorder. Neuropsychobiology 2007; 55:123-31. [PMID: 17641532 DOI: 10.1159/000106054] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Accepted: 03/24/2007] [Indexed: 11/19/2022]
Abstract
RATIONALE In the context of bipolar disorder (BPD) research it was demonstrated that administration of the structurally dissimilar mood stabilizers lithium and valproate produced a striking reduction in protein kinase C (PKC) in rat brain. In a small clinical study, tamoxifen (a PKC inhibitor) had antimanic efficacy. However, both lithium and valproate exert many biochemical changes and attribution of therapeutic relevance to any molecular findings needs to be based on linking them to behavioral effects. OBJECTIVES The present study was designed to explore such relationship by studying the effects of PKC inhibition in amphetamine-induced behavioral animal models of mania and changes in GAP-43. METHODS The effects of two daily tamoxifen (1 mg/kg) i.p. injections on acute or chronic (7 injections) amphetamine (0.5 mg/kg) -induced behaviors and GAP-43 phosphorylation were tested. RESULTS The study demonstrates that tamoxifen significantly reduced amphetamine-induced hyperactivity in a large open field without affecting spontaneous activity levels and normalized amphetamine-induced increase in visits to the center of an open field (representing risk-taking behavior). Tamoxifen also attenuated amphetamine-induced phosphorylation of GAP-43, a result that is consistent with the behavioral findings. CONCLUSIONS These results support the possibility that PKC signaling may play an important role in the pathophysiology and treatment of BPD. These findings may have direct clinical implications as they offer a new avenue for attempts to develop more specific drugs for the disorder.
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Affiliation(s)
- Haim Einat
- University of Minnesota, College of Pharmacy, Duluth, MN 55812, USA.
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Liste I, García-García E, Bueno C, Martínez-Serrano A. Bcl-XL modulates the differentiation of immortalized human neural stem cells. Cell Death Differ 2007; 14:1880-92. [PMID: 17673921 DOI: 10.1038/sj.cdd.4402205] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Understanding basic processes of human neural stem cell (hNSC) biology and differentiation is crucial for the development of cell replacement therapies. Bcl-X(L) has been reported to enhance dopaminergic neuron generation from hNSCs and mouse embryonic stem cells. In this work, we wanted to study, at the cellular level, the effects that Bcl-X(L) may exert on cell death during differentiation of hNSCs, and also on cell fate decisions and differentiation. To this end, we have used both v-myc immortalized (hNS1 cell line) and non-immortalized neurosphere cultures of hNSCs. In culture, using different experimental settings, we have consistently found that Bcl-X(L) enhances neuron generation while precluding glia generation. These effects do not arise from a glia-to-neuron shift (changes in fate decisions taken by precursors) or by only cell death counteraction, but, rather, data point to Bcl-X(L) increasing proliferation of neuronal progenitors, and inhibiting the differentiation of glial precursors. In vivo, after transplantation into the aged rat striatum, Bcl-X(L) overexpressing hNS1 cells generated more neurons and less glia than the control ones, confirming the results obtained in vitro. These results indicate an action of Bcl-X(L) modulating hNSCs differentiation, and may be thus important for the future development of cell therapy strategies for the diseased mammalian brain.
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Affiliation(s)
- I Liste
- Department of Molecular Biology and Center of Molecular Biology Severo Ochoa, Autonomous University of Madrid-C.S.I.C. Campus Cantoblanco 28049, Madrid, Spain.
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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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20
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Meidinger MA, Hildebrandt-Schoenfeld H, Illing RB. Cochlear damage induces GAP-43 expression in cholinergic synapses of the cochlear nucleus in the adult rat: a light and electron microscopic study. Eur J Neurosci 2007; 23:3187-99. [PMID: 16820009 DOI: 10.1111/j.1460-9568.2006.04853.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: 02/02/2023]
Abstract
Recent studies suggest a potential for activity-dependent reconstruction in the adult mammalian brainstem that exceeds previous expectations. We found that a unilateral cochlear lesion led within 1 week to a rise of choline acetyltransferase (ChAT) immunoreactivity in the ventral cochlear nucleus of the affected side, matching the lesion-induced expression of growth-associated protein 43 (GAP-43) previously described. The rise of both ChAT and GAP-43 immunoreactivity was reflected in the average density of the staining. Moreover, the number of light-microscopically identifiable boutons increased in both stains. GAP-43-positive boutons could, by distinct ultrastructural features, regularly be identified as presynaptic endings. However, GAP-43 immunoreactivity was not only found in presynaptic endings with a classical morphology, but also in profiles that suggest morphological dynamic structures by showing filopodia, assemblages of pleomorphic vesicles, large vesicles (diameter up to 200 nm) fusing with the presynaptic plasma membrane close to synaptic contacts, small dense-core vesicles (diameter about 80 nm) and presynaptic ribosomes. Moreover, we observed perforated synapses as well as GAP-43 immunoreactivity condensed in rafts, both indicative of growing or changing neuronal connections. Classical and untypical ultrastructural profiles that contained GAP-43 also contained ChAT. We conclude that there is extensive deafness-induced GAP-43-mediated synaptic plasticity in the cochlear nucleus, and that this plasticity is predominantly, if not exclusively, based on cholinergic afferents.
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Affiliation(s)
- Markus A Meidinger
- Neurobiological Research Laboratory, Department of Otorhinolaryngology, University of Freiburg, D-79106 Freiburg, Germany
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21
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Botto L, Masserini M, Palestini P. Changes in the composition of detergent-resistant membrane domains of cultured neurons following protein kinase C activation. J Neurosci Res 2007; 85:443-50. [PMID: 17086551 DOI: 10.1002/jnr.21111] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Changes in the composition of cell fractions, and in particular of detergent-resistant membranes (DRM) isolated from cultured rat cerebellar granule cells, were taken as possible changes in lipid raft composition during a signal transduction event. After activation of protein kinase C (PKC) with phorbol esters (PMA) or glutamate, the content of PKC and of proteins highly enriched (GAP43, Fyn, and PrP(c)) or not (MARCKS) in DRM was followed. PKC activation strongly increased its association with membranes (from 2% to 75%), causing its enrichment within DRM; the substrate GAP43, enriched in DRM, remained membrane associated, but its proportion in DRM dramatically decreased (from about 40% to 2.5%), suggesting its shift from raft to nonraft membranes, possibly as a consequence of phosphorylation by PKC. The distribution of Fyn and PrP(c) (DRM-enriched) and of MARCKS (present mainly outside DRM) did not change. PKC activation was followed by an increase of GAP43 and MARCKS phosphorylation (about 7- and 8-fold, respectively). Noteworthy was that, after cell treatment with the lipid raft-disrupting drug methyl-beta-cyclodextrin, PKC activation occurred normally, followed by MARCKS phosphorylation, but GAP43 phosphorylation did not occur. Taken altogether, these data suggest that the integrity of lipid rafts is necessary for PKC to affect GAP43 and catalyze its phosphorylation.
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Affiliation(s)
- L Botto
- Department of Experimental Medicine (DIMS), Medical School, University of Milano-Bicocca, Monza, Italy
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Stupp T, Naskar R, Thanos S. Growth-associated protein-43 expression in the lens of rats and primates. Neuroreport 2007; 18:7-11. [PMID: 17259852 DOI: 10.1097/wnr.0b013e3280109e9d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Growth-associated protein-43 is a specific neuronal protein that regulates differentiation, growth and plasticity. In the present study, growth-associated protein-43 expression was studied in the lens of rats and primates (including man) at different postnatal ages by immunoblotting, immunohistochemistry and quantitative real-time polymerase chain reaction. Growth-associated protein-43 was expressed at all ages in primates and in developing, but not in adult rats. We demonstrate that the lens - a tissue that is devoid of nerves - expresses growth-associated protein-43 throughout life in primates, and in rats during development but not in adulthood. These results suggest that growth-associated protein-43 is involved in differentiation processes also outside the nervous system.
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Affiliation(s)
- Tobias Stupp
- Department of Experimental Ophthalmology, University Eye Hospital, Münster, Germany
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23
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Abstract
Accessory proteins involved in signal processing through heterotrimeric G proteins are generally defined as proteins distinct from G protein-coupled receptor (GPCR), G protein, or classical effectors that regulate the strength/efficiency/specificity of signal transfer upon receptor activation or position these entities in the right microenvironment, contributing to the formation of a functional signal transduction complex. A flurry of recent studies have implicated an additional class of accessory proteins for this system that provide signal input to heterotrimeric G proteins in the absence of a cell surface receptor, serve as alternative binding partners for G protein subunits, provide unexpected modes of G protein regulation, and have introduced additional functional roles for G proteins. This group of accessory proteins includes the recently discovered Activators of G protein Signaling (AGS) proteins identified in a functional screen for receptor-independent activators of G protein signaling as well as several proteins identified in protein interaction screens and genetic screens in model organisms. These accessory proteins may influence GDP dissociation and nucleotide exchange at the G(alpha) subunit, alter subunit interactions within heterotrimeric G(alphabetagamma) independent of nucleotide exchange, or form complexes with G(alpha) or G(betagamma) independent of the typical G(alphabetagamma) heterotrimer. AGS and related accessory proteins reveal unexpected diversity in G protein subunits as signal transducers within the cell.
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Affiliation(s)
- Motohiko Sato
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, LA 70112, 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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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: 96] [Impact Index Per Article: 5.1] [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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Schmidt JT. Activity-driven sharpening of the retinotectal projection: the search for retrograde synaptic signaling pathways. ACTA ACUST UNITED AC 2004; 59:114-33. [PMID: 15007831 DOI: 10.1002/neu.10343] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Patterned visual activity, acting via NMDA receptors, refines developing retinotectal maps by shaping individual retinal arbors. Because NMDA receptors are postsynaptic but the retinal arbors are presynaptic, there must be retrograde signals generated downstream of Ca(++) entry through NMDA receptors that direct the presynaptic retinal terminals to stabilize and grow or to withdraw. This review defines criteria for retrograde synaptic messengers, and then applies them to the leading candidates: nitric oxide (NO), brain-derived neurotrophic factor (BDNF), and arachidonic acid (AA). NO is not likely to be a general mechanism, as it operates only in selected projections of warm blooded vertebrates to speed up synaptic refinement, but is not essential. BDNF is a neurotrophin with strong growth promoting properties and complex interactions with activity both in its release and receptor signaling, but may modulate rather than mediate the retrograde signaling. AA promotes growth and stabilization of synaptic terminals by tapping into a pre-existing axonal growth-promoting pathway that is utilized by L1, NCAM, N-cadherin, and FGF and acts via PKC, GAP43, and F-actin stabilization, and it shares some overlap with BDNF pathways. The actions of both are consistent with recent demonstrations that activity-driven stabilization includes directed growth of new synaptic contacts. Certain nondiffusible factors (synapse-specific CAMs, ephrins, neurexin/neuroligin, and matrix molecules) may also play a role in activity-driven synapse stabilization. Interactions between these pathways are discussed.
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Affiliation(s)
- John T Schmidt
- Department of Biological Sciences and Center for Neuroscience Research, University at Albany-SUNY, 1400 Washington Avenue, Albany, New York 12222, USA.
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Soto I, Marie B, Baro DJ, Blanco RE. FGF-2 modulates expression and distribution of GAP-43 in frog retinal ganglion cells after optic nerve injury. J Neurosci Res 2003; 73:507-17. [PMID: 12898535 DOI: 10.1002/jnr.10673] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Basic fibroblast growth factor (bFGF or FGF-2) has been implicated as a trophic factor that promotes survival and neurite outgrowth of neurons. We found previously that application of FGF-2 to the proximal stump of the injured axon increases retinal ganglion cell (RGC) survival. We determine here the effect of FGF-2 on expression of the axonal growth-associated phosphoprotein (GAP)-43 in retinal ganglion cells and tectum of Rana pipiens during regeneration of the optic nerve. In control retinas, GAP-43 protein was found in the optic fiber layer and in optic nerve; mRNA levels were low. After axotomy, mRNA levels increased sevenfold and GAP-43 protein was significantly increased. GAP-43 was localized in retinal axons and in a subset of RGC cell bodies and dendrites. This upregulation of GAP-43 was sustained through the period in which retinal axons reconnect with their target in the tectum. FGF-2 application to the injured nerve, but not to the eyeball, increased GAP-43 mRNA in the retina but decreased GAP-43 protein levels and decreased the number of immunopositive cell bodies. In the tectum, no treatment affected GAP-43 mRNA but FGF-2 application to the axotomized optic nerve increased GAP-43 protein in regenerating retinal projections. We conclude that FGF-2 upregulates the synthesis and alters the distribution of the axonal growth-promoting protein GAP-43, suggesting that it may enhance axonal regrowth.
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Affiliation(s)
- Ileana Soto
- Department of Anatomy, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico
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Caprini M, Gomis A, Cabedo H, Planells-Cases R, Belmonte C, Viana F, Ferrer-Montiel A. GAP43 stimulates inositol trisphosphate-mediated calcium release in response to hypotonicity. EMBO J 2003; 22:3004-14. [PMID: 12805215 PMCID: PMC162146 DOI: 10.1093/emboj/cdg294] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The identification of osmo/mechanosensory proteins in mammalian sensory neurons is still elusive. We have used an expression cloning approach to screen a human dorsal root ganglion cDNA library to look for proteins that respond to hypotonicity by raising the intracellular Ca(2+) concentration ([Ca(2+)](i)). We report the unexpected identification of GAP43 (also known as neuromodulin or B50), a membrane-anchored neuronal protein implicated in axonal growth and synaptic plasticity, as an osmosensory protein that augments [Ca(2+)](i) in response to hypotonicity. Palmitoylation of GAP43 plays an important role in the protein osmosensitivity. Depletion of intracellular stores or inhibition of phospholipase C (PLC) activity abrogates hypotonicity-evoked, GAP43-mediated [Ca(2+)](i) elevations. Notably, hypotonicity promoted the selective association of GAP43 with the PLC-delta(1) isoform, and a concomitant increase in inositol-1,4,5-trisphosphate (IP(3)) formation. Collectively, these findings indicate that hypo-osmotic activation of GAP43 induces Ca(2+) release from IP(3)-sensitive intracellular stores. The osmosensitivity of GAP43 furnishes a mechanistic framework that links axon elongation with phospho inositide metabolism, spontaneous triggering of cytosolic Ca(2+) transients and the regulation of actin dynamics and motility at the growth cone in response to temporal and local mechanical forces.
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Affiliation(s)
- Marco Caprini
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, 03202 Alicante, Spain
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Park JU, Tsuchiya T. Increase in gap junctional intercellular communication by high molecular weight hyaluronic acid associated with fibroblast growth factor 2 and keratinocyte growth factor production in normal human dermal fibroblasts. TISSUE ENGINEERING 2002; 8:419-27. [PMID: 12167228 DOI: 10.1089/107632702760184682] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The effects of different molecular weights of hyaluronic acid (HA), a major component of extracellular matrix, on gap junctional intercellular communication (GJIC) in normal human dermal fibroblasts (NHDF cells) were investigated. NHDF cells were cultured for 4 days with different molecular weights of HA and then the extent of GJIC was assessed by the scrape-loading dye transfer method, using Lucifer yellow. The area of dye transfer was greater in the dishes coated with HA than in those to which HA was added. Thus, NHDF cells cultured on surfaces coated with high molecular weight (HMW) HA (MW, 800 kDa) showed greatly enhanced GJIC. Furthermore, another aim of this study was to evaluate the effects of different molecular weights of HA on the production of FGF-2 and KGF, because both are important cytokines produced by NHDF cells. When FGF-2 and KGF cultured levels of cell extracts and media were determined by ELISA, both levels were significantly enhanced when cells were grown on plates coated with HMW HA. This finding indicated that the function of gap junction channels in NHDF cells grown on plates coated with HMW HA may promote the biosynthesis of growth factors such as FGF-2 and KGF.
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Affiliation(s)
- Jeong Ung Park
- Division of Medical Devices, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
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Growth-associated protein-43 is required for commissural axon guidance in the developing vertebrate nervous system. J Neurosci 2002. [PMID: 11756507 DOI: 10.1523/jneurosci.22-01-00239.2002] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Growth-associated protein-43 (GAP-43) is a major growth cone protein whose phosphorylation by PKC in response to extracellular guidance cues can regulate F-actin behavior. Here we show that 100% of homozygote GAP-43 (-/-) mice failed to form the anterior commissure (AC), hippocampal commissure (HC), and corpus callosum (CC) in vivo. Instead, although midline fusion was normal, selective fasciculation between commissural axons was inhibited, and TAG-1-labeled axons tangled bilaterally into Probst's bundles. Moreover, their growth cones had significantly smaller lamellas and reduced levels of F-actin in vitro. Likewise, 100% of GAP-43 (+/-) mice with one disrupted allele also showed defects in HC and CC, whereas the AC was unaffected. Individual GAP-43 (+/-) mice could be assigned to two groups based on the amount that PKC phosphorylation of GAP-43 was reduced in neocortical neurons. In mice with approximately 1% phosphorylation, the HC and CC were absent, whereas in mice with approximately 10% phosphorylation, the HC and CC were smaller. Both results suggest that PKC-mediated signaling in commissural axons may be defective. However, although Probst's bundles formed consistently at the location of the glial wedge, both GAP-43 (-/-) and GAP-43 (+/+) cortical axons were still repulsed by Slit-2 in vitro, precluding failure of this deflective signal from the glial wedge as the source of the phenotype. Nonetheless, the data show that a functional threshold of GAP-43 is required for commissure formation and suggests that failure to regulate F-actin in commissural growth cones may be related to inhibited PKC phosphorylation of GAP-43.
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