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Liang YY, Liao XY, Jia JJ, Yin YZ, Zhang YH, Gao FG. K33 only mutant ubiquitin augments bone marrow-derived dendritic cell-mediated CTL priming via PI3K-Akt pathway. Immunology 2024; 172:486-499. [PMID: 38547355 DOI: 10.1111/imm.13787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 03/18/2024] [Indexed: 06/15/2024] Open
Abstract
To explore the effect of K33 only mutant ubiquitin (K33O) on bone marrow-derived dendritic cells' (BMDCs') maturity, antigen uptake capability, surface molecule expressions and BMDC-mediated CTL priming, and further investigate the role of PI3K-Akt engaged in K33O-increased BMDC maturation, antigen uptake and presentation, surface molecule expressions and BMDC-based CTL priming. BMDCs were conferred K33O and other ubiquitin mutants (K33R, K48R, K63R-mutant ubiquitin) incubation or LY294002 and wortmannin pretreatment. PI3K-Akt phosphorylation, antigen uptake, antigenic presentation and CD86/MHC class I expression in BMDC were determined by western blot or flow cytometry. BMDC-based CTL proliferation and priming were determined by in vitro mixed lymphocyte reaction (MLR), ex vivo enzyme-linked immunospot assay (Elispot) and flow cytometry with intracellular staining, respectively. The treatment with K33O effectively augmented PI3K-Akt phosphorylation, BMDCs' antigen uptake, antigenic presentation, CD86/MHC class I and CD11c expressions. MLR, Elispot and flow cytometry revealed that K33O treatment obviously enhanced CTL proliferation, CTL priming and perforin/granzyme B expression. The pretreatment with PI3K-Akt inhibitors efficiently abrogated K33O's effects on BMDC. The replenishment of K33 only mutant ubiquitin augments BMDC-mediated CTL priming in bone marrow-derived dendritic cells via PI3K-Akt signalling.
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Affiliation(s)
- Yi Yun Liang
- Department of Basic Medicine Science, School of Medicine, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Xiao Yan Liao
- Department of Basic Medicine Science, School of Medicine, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Jun Jun Jia
- Department of Basic Medicine Science, School of Medicine, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Yi Zhen Yin
- Department of Basic Medicine Science, School of Medicine, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Yue Hua Zhang
- Laboratory Animal Center, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Feng Guang Gao
- Department of Basic Medicine Science, School of Medicine, Xiamen University, Xiamen, Fujian, People's Republic of China
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2
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Mora-Zenil J, Morán J. ROS produced by NOX promote the neurite growth in a PI3K/Akt independent manner. J Neurosci Res 2024; 102:e25259. [PMID: 37840360 DOI: 10.1002/jnr.25259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 05/17/2023] [Accepted: 09/28/2023] [Indexed: 10/17/2023]
Abstract
Reactive oxygen species (ROS) function as signaling molecules in several physiologic and pathologic processes. In central nervous system, ROS are critical for differentiation, migration, polarization, and neurite growth. These actions are mediated by reversible oxidation of target proteins. On the other hand, PI3K/Akt signaling pathway is susceptible to be modulated by ROS and it has been implicated in neurite growth. In this study, we evaluated the participation of ROS in the neurite growth of cultured rat cerebellar granule neurons (CGN), as well as the possible regulation of the PI3K/Akt pathway by ROS during neurite outgrowth. For this purpose, CGN were treated with cellular or mitochondrial antioxidants, or an NOX inhibitor and neurite growth was evaluated. Moreover, to assess the participation Akt in this process, the p-Akt levels were measured in CGN treated with antioxidants or a NOX inhibitor. The effect of antioxidants on the neurite growth in the presence of a PI3K inhibitor was also measured. We found that cellular antioxidants and the NOX inhibitor decreased the neurite growth, but not the mitochondrial antioxidant. Interestingly, the antioxidants increased the p-Akt levels; however, the effect of antioxidants on neurite growth was no dependent on the Akt activity since the inhibitor of PI3K did not modify the antioxidant action on neurite growth. Our results show that the PI3K/Akt pathway participates in neurite growth and that ROS produced by NOX could function as signals in this process; however, this action is not mediated by a redox regulation of Akt activity.
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Affiliation(s)
- Janeth Mora-Zenil
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Julio Morán
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
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3
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Gu X, Jia C, Wang J. Advances in Understanding the Molecular Mechanisms of Neuronal Polarity. Mol Neurobiol 2023; 60:2851-2870. [PMID: 36738353 DOI: 10.1007/s12035-023-03242-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 01/22/2023] [Indexed: 02/05/2023]
Abstract
The establishment and maintenance of neuronal polarity are important for neural development and function. Abnormal neuronal polarity establishment commonly leads to a variety of neurodevelopmental disorders. Over the past three decades, with the continuous development and improvement of biological research methods and techniques, we have made tremendous progress in the understanding of the molecular mechanisms of neuronal polarity establishment. The activity of positive and negative feedback signals and actin waves are both essential in this process. They drive the directional transport and aggregation of key molecules of neuronal polarity, promote the spatiotemporal regulation of ordered and coordinated interactions of actin filaments and microtubules, stimulate the specialization and growth of axons, and inhibit the formation of multiple axons. In this review, we focus on recent advances in these areas, in particular the important findings about neuronal polarity in two classical models, in vitro primary hippocampal/cortical neurons and in vivo cortical pyramidal neurons, and discuss our current understanding of neuronal polarity..
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Affiliation(s)
- Xi Gu
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.
| | - Chunhong Jia
- Department of Pediatrics, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
| | - Junhao Wang
- Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
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4
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Khan TA, Guo A, Martin J, Te Chien C, Liu T, Szczurkowska J, Shelly M. Directed mechanisms for apical dendrite development during neuronal polarization. Dev Biol 2022; 490:110-116. [PMID: 35809631 DOI: 10.1016/j.ydbio.2022.07.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 06/09/2022] [Accepted: 07/01/2022] [Indexed: 12/18/2022]
Abstract
The development of the dendrite and the axon during neuronal polarization underlies the directed flow of information in the brain. Seminal studies on axon development have dominated the mechanistic analysis of neuronal polarization. These studies, many originating from examinations in cultured hippocampal and cortical neurons in vitro, have established a prevalent view that axon formation precedes and is necessary for neuronal polarization. There is also in vivo evidence supporting this view. Nevertheless, the establishment of bipolar polarity and the leading edge, and apical dendrite development in pyramidal neurons in vivo occur when axon formation is prevented. Furthermore, recent mounting evidence suggest that directed mechanisms might mediate bipolar polarity/leading process and subsequent apical dendrite development. In the presence of spatially directed extracellular cues in the developing brain, these events may operate independently of axon forming events. In this perspective we summarize evidence in support of these evolving views in neuronal polarization and highlight recent findings on dedicated mechanisms acting in apical dendrite development.
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Affiliation(s)
- Tamor A Khan
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794-5230, USA
| | - Alan Guo
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794-5230, USA
| | - Jacqueline Martin
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794-5230, USA
| | - Chia Te Chien
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794-5230, USA
| | - Tianrui Liu
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794-5230, USA
| | - Joanna Szczurkowska
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794-5230, USA
| | - Maya Shelly
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794-5230, USA.
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5
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Cassioli C, Baldari CT. Lymphocyte Polarization During Immune Synapse Assembly: Centrosomal Actin Joins the Game. Front Immunol 2022; 13:830835. [PMID: 35222415 PMCID: PMC8873515 DOI: 10.3389/fimmu.2022.830835] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/20/2022] [Indexed: 11/13/2022] Open
Abstract
Interactions among immune cells are essential for the development of adaptive immune responses. The immunological synapse (IS) provides a specialized platform for integration of signals and intercellular communication between T lymphocytes and antigen presenting cells (APCs). In the T cell the reorganization of surface molecules at the synaptic interface is initiated by T cell receptor binding to a cognate peptide-major histocompatibility complex on the APC surface and is accompanied by a polarized remodelling of the cytoskeleton and centrosome reorientation to a subsynaptic position. Although there is a general agreement on polarizing signals and mechanisms driving centrosome reorientation during IS assembly, the primary events that prepare for centrosome repositioning remain largely unexplored. It has been recently shown that in resting lymphocytes a local polymerization of filamentous actin (F-actin) at the centrosome contributes to anchoring this organelle to the nucleus. During early stages of IS formation centrosomal F-actin undergoes depletion, allowing for centrosome detachment from the nucleus and its polarization towards the synaptic membrane. We recently demonstrated that in CD4+ T cells the reduction in centrosomal F-actin relies on the activity of a centrosome-associated proteasome and implicated the ciliopathy-related Bardet-Biedl syndrome 1 protein in the dynein-dependent recruitment of the proteasome 19S regulatory subunit to the centrosome. In this short review we will feature our recent findings that collectively provide a new function for BBS proteins and the proteasome in actin dynamics, centrosome polarization and T cell activation.
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Hong JC, Fan HC, Yang PJ, Lin DW, Wu HC, Huang HC. Localized Proteolysis for the Construction of Intracellular Asymmetry in Escherichia coli. ACS Synth Biol 2021; 10:1830-1836. [PMID: 34374512 DOI: 10.1021/acssynbio.1c00200] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protein-level regulations have gained importance in building synthetic circuits, as they offer a potential advantage in the speed of operation compared to gene regulation circuits. In nature, localized protein degradation is prevalent in polarizing cellular signaling. We, therefore, set out to systematically investigate whether localized proteolysis can be employed to construct intracellular asymmetry in Escherichia coli. We demonstrate that, by inserting a cognate cleavage site between the reporter and C-terminal degron, the unstable reporter can be stabilized in the presence of the tobacco etch virus protease. Furthermore, the split protease can be functionally reconstituted by the PopZ-based polarity system to exert localized proteolysis. Selective stabilization of the unstable reporter at the PopZ pole can lead to intracellular asymmetry in E. coli. Our study provides complementary evidence to support that localized proteolysis may be a strategy for polarization in developmental cell biology. Circuits designed in this study may also help to expand the synthetic biology repository for the engineering of synthetic morphogenesis, particularly for processes that require rapid control of local protein abundance.
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Affiliation(s)
- Jui-Chung Hong
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Hao-Chun Fan
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Po-Jiun Yang
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Da-Wei Lin
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Hsuan-Chen Wu
- Department of Biochemical Science and Technology, National Taiwan University, Taipei 10617, Taiwan
| | - Hsiao-Chun Huang
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
- Department of Life Science, National Taiwan University, Taipei 10617, Taiwan
- Genome and Systems Biology Degree Program, National Taiwan University, Taipei 10617, Taiwan
- Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan
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7
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Pinto MJ, Tomé D, Almeida RD. The Ubiquitinated Axon: Local Control of Axon Development and Function by Ubiquitin. J Neurosci 2021; 41:2796-2813. [PMID: 33789876 PMCID: PMC8018891 DOI: 10.1523/jneurosci.2251-20.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 01/15/2021] [Accepted: 01/22/2021] [Indexed: 02/01/2023] Open
Abstract
Ubiquitin tagging sets protein fate. With a wide range of possible patterns and reversibility, ubiquitination can assume many shapes to meet specific demands of a particular cell across time and space. In neurons, unique cells with functionally distinct axons and dendrites harboring dynamic synapses, the ubiquitin code is exploited at the height of its power. Indeed, wide expression of ubiquitination and proteasome machinery at synapses, a diverse brain ubiquitome, and the existence of ubiquitin-related neurodevelopmental diseases support a fundamental role of ubiquitin signaling in the developing and mature brain. While special attention has been given to dendritic ubiquitin-dependent control, how axonal biology is governed by this small but versatile molecule has been considerably less discussed. Herein, we set out to explore the ubiquitin-mediated spatiotemporal control of an axon's lifetime: from its differentiation and growth through presynaptic formation, function, and pruning.
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Affiliation(s)
- Maria J Pinto
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, 3004-504, Portugal
| | - Diogo Tomé
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, 3004-504, Portugal
- Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Aveiro, 3810-193, Portugal
| | - Ramiro D Almeida
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, 3004-504, Portugal
- Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Aveiro, 3810-193, Portugal
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8
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Axonal Organelles as Molecular Platforms for Axon Growth and Regeneration after Injury. Int J Mol Sci 2021; 22:ijms22041798. [PMID: 33670312 PMCID: PMC7918155 DOI: 10.3390/ijms22041798] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023] Open
Abstract
Investigating the molecular mechanisms governing developmental axon growth has been a useful approach for identifying new strategies for boosting axon regeneration after injury, with the goal of treating debilitating conditions such as spinal cord injury and vision loss. The picture emerging is that various axonal organelles are important centers for organizing the molecular mechanisms and machinery required for growth cone development and axon extension, and these have recently been targeted to stimulate robust regeneration in the injured adult central nervous system (CNS). This review summarizes recent literature highlighting a central role for organelles such as recycling endosomes, the endoplasmic reticulum, mitochondria, lysosomes, autophagosomes and the proteasome in developmental axon growth, and describes how these organelles can be targeted to promote axon regeneration after injury to the adult CNS. This review also examines the connections between these organelles in developing and regenerating axons, and finally discusses the molecular mechanisms within the axon that are required for successful axon growth.
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9
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Wilson C, Cáceres A. New insights on epigenetic mechanisms supporting axonal development: histone marks and miRNAs. FEBS J 2020; 288:6353-6364. [PMID: 33332753 DOI: 10.1111/febs.15673] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/21/2020] [Accepted: 12/15/2020] [Indexed: 11/27/2022]
Abstract
Mechanisms supporting axon growth and the establishment of neuronal polarity have remained largely disconnected from their genetic and epigenetic fundamentals. Recently, post-transcriptional modifications of histones involved in chromatin folding and transcription, and microRNAs controlling translation have emerged as regulators of axonal specification, growth, and guidance. In this article, we review novel evidence supporting the concept that epigenetic mechanisms work at both transcriptional and post-transcriptional levels to shape axons. We also discuss the role of splicing on axonal growth, as one of the most (if not the most) powerful post-transcriptional mechanism to diversify genetic information. Overall, we think exploring the gap between epigenetics and axonal growth raises new questions and perspectives to the development of axons in physiological and pathological contexts.
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Affiliation(s)
- Carlos Wilson
- Centro de Investigación en Medicina Traslacional "Severo R Amuchástegui" (CIMETSA), Instituto Universitario Ciencias Biomédicas Córdoba (IUCBC), Córdoba, Argentina.,Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC-CONICET-UNC), Córdoba, Argentina.,Universidad Nacional de Córdoba (UNC), Argentina
| | - Alfredo Cáceres
- Centro de Investigación en Medicina Traslacional "Severo R Amuchástegui" (CIMETSA), Instituto Universitario Ciencias Biomédicas Córdoba (IUCBC), Córdoba, Argentina
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10
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Bhaskar S, Gowda J, Prasanna J, Kumar A. Does altering proteasomal activity and trafficking reduce the arborization mediated specific vulnerability of SNpc dopaminergic neurons of Parkinson's disease? Med Hypotheses 2020; 143:110062. [PMID: 32652429 DOI: 10.1016/j.mehy.2020.110062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/27/2020] [Indexed: 01/15/2023]
Abstract
Parkinson's disease (PD) is a late-onset degenerative neuronal disorder and stands second among the neurological disorders with 1% of the total world population being affected. The disease originates majorly due to compromised function of the dopaminergic (DA) neurons in the Substantia Nigra pars compacta (SNpc), but not the ventral tegmental area (VTA) region of the midbrain. The differential susceptibility for degeneration is majorly attributed to morphological, molecular, and electrophysiological heterogeneity existing in DA neurons of SNpc and VTA. Long-range axonal arborization and a higher number of synapses in SNpc DA neurons make it more vulnerable compared to VTA DA neurons. Studies have shown that a decrease in such axonal arborization places DA neurons at decreased risk in PD. The two well established underlying mechanisms are a) As arborization is an energy-demanding process, increased redistribution of mitochondria to the axonal terminals occurs to satisfy the bioenergetic requirement b) The stabilization of axon-promoting factors at the axonal tip is an essential component for enhancing the arborization process. Interfering with any of these two processes would probably alleviate the degeneration of SNpc DA neurons. To accomplish the decreased stability of arborizing factors and thereby increase the resilience of SNpc DA neurons, we hypothesize the activation of anterograde transport-dependent recruitment of proteasomes to axon terminals as one of the most favorable approaches. Understanding this putative avenue of enhancing proteasomal activity and migration to the axonal tip could provide insight into the progression of neurodegeneration in PD and possibly offer a novel therapeutic strategy.
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Affiliation(s)
- Smitha Bhaskar
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Allalsandra, Yelahanka, Bengaluru 560065, Karnataka, India
| | - Jeevan Gowda
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Allalsandra, Yelahanka, Bengaluru 560065, Karnataka, India
| | - Jyothi Prasanna
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Allalsandra, Yelahanka, Bengaluru 560065, Karnataka, India
| | - Anujith Kumar
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Allalsandra, Yelahanka, Bengaluru 560065, Karnataka, India.
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11
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Kim HR, Kim DH, An JY, Kang D, Park JW, Hwang EM, Seo EJ, Jang IH, Ha CM, Lee BJ. NELL2 Function in Axon Development of Hippocampal Neurons. Mol Cells 2020; 43:581-589. [PMID: 32597395 PMCID: PMC7332358 DOI: 10.14348/molcells.2020.0032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 05/06/2020] [Accepted: 05/24/2020] [Indexed: 02/07/2023] Open
Abstract
Neurons have multiple dendrites and single axon. This neuronal polarity is gradually established during early processes of neuronal differentiation: generation of multiple neurites (stages 1-2); differentiation (stage 3) and maturation (stages 4-5) of an axon and dendrites. In this study, we demonstrated that the neuron-specific n-glycosylated protein NELL2 is important for neuronal polarization and axon growth using cultured rat embryonic hippocampal neurons. Endogenous NELL2 expression was gradually increased in parallel with the progression of developmental stages of hippocampal neurons, and overexpression of NELL2 stimulated neuronal polarization and axon growth. In line with these results, knockdown of NELL2 expression resulted in deterioration of neuronal development, including inhibition of neuronal development progression, decreased axon growth and increased axon branching. Inhibitor against extracellular signal-regulated kinase (ERK) dramatically inhibited NELL2-induced progression of neuronal development and axon growth. These results suggest that NELL2 is an important regulator for the morphological development for neuronal polarization and axon growth.
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Affiliation(s)
- Han Rae Kim
- Department of Biological Sciences, College of Natural Sciences, University of Ulsan, Ulsan 4460, Korea
- Present address: Department of Pharmacology and Physiology, School of Medicine & Health Sciences, The George Washington University, Washington, D.C. 20037, USA
- These authors contributed equally to this work.
| | - Dong Hee Kim
- Department of Biological Sciences, College of Natural Sciences, University of Ulsan, Ulsan 4460, Korea
- These authors contributed equally to this work.
| | - Ji Young An
- Department of Biological Sciences, College of Natural Sciences, University of Ulsan, Ulsan 4460, Korea
- These authors contributed equally to this work.
| | - Dasol Kang
- Department of Biological Sciences, College of Natural Sciences, University of Ulsan, Ulsan 4460, Korea
| | - Jeong Woo Park
- Department of Biological Sciences, College of Natural Sciences, University of Ulsan, Ulsan 4460, Korea
| | - Eun Mi Hwang
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 079, Korea
| | - Eun Jin Seo
- Department of Oral Biochemistry, Dental and Life Science Institute, Pusan National University School of Dentistry, Yangsan 50612, Korea
| | - Il Ho Jang
- Department of Oral Biochemistry, Dental and Life Science Institute, Pusan National University School of Dentistry, Yangsan 50612, Korea
| | - Chang Man Ha
- Research Division and Brain Research Core Facilities of Korea Brain Research Institute, Daegu 1068, Korea,
| | - Byung Ju Lee
- Department of Biological Sciences, College of Natural Sciences, University of Ulsan, Ulsan 4460, Korea
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12
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Cespedes A, Villa M, Benito-Cuesta I, Perez-Alvarez MJ, Ordoñez L, Wandosell F. Energy-Sensing Pathways in Ischemia: The Counterbalance Between AMPK and mTORC. Curr Pharm Des 2020; 25:4763-4770. [PMID: 31820693 DOI: 10.2174/1381612825666191210152156] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 12/06/2019] [Indexed: 01/02/2023]
Abstract
Stroke is an important cause of death and disability, and it is the second leading cause of death worldwide. In humans, middle cerebral artery occlusion (MCAO) is the most common cause of ischemic stroke. The damage occurs due to the lack of nutrients and oxygen contributed by the blood flow. The present review aims to analyze to what extent the lack of each of the elements of the system leads to damage and which mechanisms are unaffected by this deficiency. We believe that the specific analysis of the effect of lack of each component could lead to the emergence of new therapeutic targets for this important brain pathology.
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Affiliation(s)
- Angel Cespedes
- Centro de Biología Molecular "Severo Ochoa". CSIC-UAM. Nicolás Cabrera 1, 28049 Madrid, Spain.,Research Group of Neurodegenerative Diseases, Department of Animal Health, Faculty of Veterinary Medicine and Zootechnics - Tolima University, Santa Helena - 730006299, Ibagué, Colombia
| | - Mario Villa
- Centro de Biología Molecular "Severo Ochoa". CSIC-UAM. Nicolás Cabrera 1, 28049 Madrid, Spain.,Departamento de Biología (Fisiología Animal). Facultad de Ciencias. Universidad Autónoma de Madrid. C/Darwin 2. 28049 Madrid, Spain
| | - Irene Benito-Cuesta
- Centro de Biología Molecular "Severo Ochoa". CSIC-UAM. Nicolás Cabrera 1, 28049 Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Maria J Perez-Alvarez
- Centro de Biología Molecular "Severo Ochoa". CSIC-UAM. Nicolás Cabrera 1, 28049 Madrid, Spain.,Departamento de Biología (Fisiología Animal). Facultad de Ciencias. Universidad Autónoma de Madrid. C/Darwin 2. 28049 Madrid, Spain
| | - Lara Ordoñez
- Centro de Biología Molecular "Severo Ochoa". CSIC-UAM. Nicolás Cabrera 1, 28049 Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Francisco Wandosell
- Centro de Biología Molecular "Severo Ochoa". CSIC-UAM. Nicolás Cabrera 1, 28049 Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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13
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Radler MR, Suber A, Spiliotis ET. Spatial control of membrane traffic in neuronal dendrites. Mol Cell Neurosci 2020; 105:103492. [PMID: 32294508 PMCID: PMC7317674 DOI: 10.1016/j.mcn.2020.103492] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 03/24/2020] [Accepted: 04/01/2020] [Indexed: 02/06/2023] Open
Abstract
Neuronal dendrites are highly branched and specialized compartments with distinct structures and secretory organelles (e.g., spines, Golgi outposts), and a unique cytoskeletal organization that includes microtubules of mixed polarity. Dendritic membranes are enriched with proteins, which specialize in the formation and function of the post-synaptic membrane of the neuronal synapse. How these proteins partition preferentially in dendrites, and how they traffic in a manner that is spatiotemporally accurate and regulated by synaptic activity are long-standing questions of neuronal cell biology. Recent studies have shed new insights into the spatial control of dendritic membrane traffic, revealing new classes of proteins (e.g., septins) and cytoskeleton-based mechanisms with dendrite-specific functions. Here, we review these advances by revisiting the fundamental mechanisms that control membrane traffic at the levels of protein sorting and motor-driven transport on microtubules and actin filaments. Overall, dendrites possess unique mechanisms for the spatial control of membrane traffic, which might have specialized and co-evolved with their highly arborized morphology.
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Affiliation(s)
- Megan R Radler
- Department of Biology, Drexel University, 3245 Chestnut St, Philadelphia, PA 19104, USA
| | - Ayana Suber
- Department of Biology, Drexel University, 3245 Chestnut St, Philadelphia, PA 19104, USA
| | - Elias T Spiliotis
- Department of Biology, Drexel University, 3245 Chestnut St, Philadelphia, PA 19104, USA.
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14
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Lucci C, Mesquita-Ribeiro R, Rathbone A, Dajas-Bailador F. Spatiotemporal regulation of GSK3β levels by miRNA-26a controls axon development in cortical neurons. Development 2020; 147:dev.180232. [PMID: 31964775 PMCID: PMC7033742 DOI: 10.1242/dev.180232] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Accepted: 12/19/2019] [Indexed: 12/17/2022]
Abstract
Both the establishment of neuronal polarity and axonal growth are crucial steps in the development of the nervous system. The local translation of mRNAs in the axon provides precise regulation of protein expression, and is now known to participate in axon development, pathfinding and synaptic formation and function. We have investigated the role of miR-26a in early stage mouse primary cortical neuron development. We show that micro-RNA-26a-5p (miR-26a) is highly expressed in neuronal cultures, and regulates both neuronal polarity and axon growth. Using compartmentalised microfluidic neuronal cultures, we identified a local role for miR-26a in the axon, where the repression of local synthesis of GSK3β controls axon development and growth. Removal of this repression in the axon triggers local translation of GSK3β protein and subsequent transport to the soma, where it can impact axonal growth. These results demonstrate how the axonal miR-26a can regulate local protein translation in the axon to facilitate retrograde communication to the soma and amplify neuronal responses, in a mechanism that influences axon development. Highlighted Article: Axonal miR-26a can regulate GSK3β translation in the axon to promote retrograde communication to the soma in a mechanism that modulates axon development.
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Affiliation(s)
- Cristiano Lucci
- School of Life Sciences, Medical School Building, University of Nottingham, NG7 2UH Nottingham, UK
| | - Raquel Mesquita-Ribeiro
- School of Life Sciences, Medical School Building, University of Nottingham, NG7 2UH Nottingham, UK
| | - Alex Rathbone
- School of Life Sciences, Medical School Building, University of Nottingham, NG7 2UH Nottingham, UK
| | - Federico Dajas-Bailador
- School of Life Sciences, Medical School Building, University of Nottingham, NG7 2UH Nottingham, UK
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15
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Ke J, Wu G, Zhang J, Li H, Gao S, Shao M, Gao Z, Sy MS, Cao Y, Yang X, Xu J, Li C. Melanoma migration is promoted by prion protein via Akt-hsp27 signaling axis. Biochem Biophys Res Commun 2019; 523:375-381. [PMID: 31870551 DOI: 10.1016/j.bbrc.2019.12.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 12/07/2019] [Indexed: 10/25/2022]
Abstract
Patients with metastatic melanoma have a poorer prognosis. Prion protein (PrP) in melanoma is known to play an important role in cancer cell migration and invasion by interacting with filamin A (FLNa), a cytolinker protein. To investigate if PrP may contribute to cancer cell mobility independent of its binding to FLNa, we knocked out PRNP in M2 melanoma cell, which lacked FLNa expression. We found that deletion of PRNP in M2 significantly reduced its motility. When PRNP was deleted, the level of Akt was decreased. As a consequence, phosphorylation of small heat shock protein (hsp27) was also reduced, which resulted in polymerization of F-actin rendering the cells less migratory. Accordingly, when PrP was re-expressed in PRNP null M2 cells, the mobility of the recurred cells was rescued, so were the expression levels of Akt and phosphorylated hsp27, resulting in a decrease in the polymerization of F-actin. These results revealed that PrP can play a FLNa independent role in cytoskeletal organization and tumor cell migration by modulating Akt-hsp27-F-actin axis.
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Affiliation(s)
- Jingru Ke
- Department of Dermatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China; Affiliated Cancer Hospital & Institute of Guangzhou Medical University, State Key Laboratory of Respiratory Diseases, 78 Hengzhigang Road, Guangzhou, 510095, China
| | - Guiru Wu
- The Joint Laboratory for Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510623, China; Wuhan Institute of Virology, Chinese Academy of Sciences, State Key Laboratory of Virology, 44 Xiao Hong Shan Zhong Qu, Wuhan, 430071, China
| | - Jie Zhang
- Affiliated Cancer Hospital & Institute of Guangzhou Medical University, State Key Laboratory of Respiratory Diseases, 78 Hengzhigang Road, Guangzhou, 510095, China; Department of Stomatology, First Affiliated Hospital, School of Medicine, Shihezi University, No. 107 North 2nd Road, Shihezi, Xinjiang, 832008, China
| | - Huan Li
- Wuhan Institute of Virology, Chinese Academy of Sciences, State Key Laboratory of Virology, 44 Xiao Hong Shan Zhong Qu, Wuhan, 430071, China
| | - Shanshan Gao
- Wuhan Institute of Virology, Chinese Academy of Sciences, State Key Laboratory of Virology, 44 Xiao Hong Shan Zhong Qu, Wuhan, 430071, China
| | - Ming Shao
- Wuhan Institute of Virology, Chinese Academy of Sciences, State Key Laboratory of Virology, 44 Xiao Hong Shan Zhong Qu, Wuhan, 430071, China
| | - Zhenxing Gao
- Affiliated Cancer Hospital & Institute of Guangzhou Medical University, State Key Laboratory of Respiratory Diseases, 78 Hengzhigang Road, Guangzhou, 510095, China
| | - Man-Sun Sy
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Yuchun Cao
- Department of Dermatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Xiaowen Yang
- Department of the First Abdominal Surgery, Jiangxi Tumor Hospital, Nanchang, Jiangxi, 330029, China.
| | - Jiang Xu
- Department of Stomatology, First Affiliated Hospital, School of Medicine, Shihezi University, No. 107 North 2nd Road, Shihezi, Xinjiang, 832008, China.
| | - Chaoyang Li
- Affiliated Cancer Hospital & Institute of Guangzhou Medical University, State Key Laboratory of Respiratory Diseases, 78 Hengzhigang Road, Guangzhou, 510095, China.
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16
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Ko HR, Jin EJ, Lee SB, Kim CK, Yun T, Cho SW, Park KW, Ahn JY. SIAH1 ubiquitin ligase mediates ubiquitination and degradation of Akt3 in neural development. J Biol Chem 2019; 294:15435-15445. [PMID: 31471318 DOI: 10.1074/jbc.ra119.009618] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/19/2019] [Indexed: 01/17/2023] Open
Abstract
Akt signaling is an important regulator of neural development, but the distinctive function of Akt isoforms in brain development presents a challenge. Here we show Siah1 as an ubiquitin ligase that preferentially interacts with Akt3 and facilitates ubiquitination and degradation of Akt3. Akt3 is enriched in the axonal shaft and branches but not growth cone tips, where Siah1 is prominently present. Depletion of Siah1 enhanced Akt3 levels in the soma and axonal tips, eliciting multiple branching. Brain-specific somatic mutation in Akt3-E17K escapes from Siah1-mediated degradation and causes improper neural development with dysmorphic neurons. Remarkably, coexpression of Siah1 with Akt3-WT restricted disorganization of neural development is caused by Akt3 overexpression, whereas forced expression of Siah1 with the Akt3-E17K mutant fails to cope with malformation of neural development. These findings demonstrate that Siah1 limits Akt3 turnover during brain development and that this event is essential for normal organization of the neural network.
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Affiliation(s)
- Hyo Rim Ko
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea.,Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Eun-Ju Jin
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea.,Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Sang Bae Lee
- Institute for Cancer Genetics, Columbia University Medical Center, New York, New York 10032
| | - Chung Kwon Kim
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea.,Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Taegwan Yun
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea.,Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Sung-Woo Cho
- Department of Biochemistry and Molecular Biology, University of Ulsan, College of Medicine, Seoul 05505, Korea
| | - Kye Won Park
- Department of Food Science and Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon 16419, Korea
| | - Jee-Yin Ahn
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea .,Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon 16419, Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul 06351, Korea
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17
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Santiago SE, Barnes AP. Neuronal Polarization Packs a One-Two Punch. Neuron 2019; 100:1007-1009. [PMID: 30521770 DOI: 10.1016/j.neuron.2018.11.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In this issue of Neuron, Ambrozkiewicz et al. (2018) define a new molecular circuit controlling neuronal polarization and migration through the transcription factor SOX9 to coordinate the production of regulators of both protein synthesis and degradation.
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Affiliation(s)
- Sarah E Santiago
- Oregon Health and Science University, Knight Cardiovascular Institute, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
| | - Anthony P Barnes
- Oregon Health and Science University, Knight Cardiovascular Institute, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
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18
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Ibañez-Vega J, Del Valle Batalla F, Saez JJ, Soza A, Yuseff MI. Proteasome Dependent Actin Remodeling Facilitates Antigen Extraction at the Immune Synapse of B Cells. Front Immunol 2019; 10:225. [PMID: 30873155 PMCID: PMC6401660 DOI: 10.3389/fimmu.2019.00225] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/28/2019] [Indexed: 12/24/2022] Open
Abstract
Engagement of the B cell receptor (BCR) with surface-tethered antigens leads to the formation of an immune synapse (IS), where cell signaling and antigen uptake are tightly coordinated. Centrosome re-orientation to the immune synapse has emerged as a critical regulatory step to guide the local recruitment and secretion of lysosomes, which can facilitate the extraction of immobilized antigens. This process is coupled to actin remodeling at the centrosome and at the immune synapse, which is crucial to promote cell polarity. How B cells balance both pools of actin cytoskeleton to achieve a polarized phenotype during the formation of an immune synapse is not fully understood. Here, we reveal that B cells rely on proteasome activity to achieve this task. The proteasome is a multi-catalytic protease that degrades cytosolic and nuclear proteins and its dysfunction is associated with diseases, such as cancer and autoimmunity. Our results show that resting B cells contain an active proteasome pool at the centrosome, which is required for efficient actin clearance at this level. As a result of proteasome inhibition, activated B cells do not deplete actin at the centrosome and are unable to separate the centrosome from the nucleus and thus display impaired polarity. Consequently, lysosome recruitment to the immune synapse, antigen extraction and presentation are severely compromised in B cells with diminished proteasome activity. Additionally, we found that proteasome inhibition leads to impaired actin remodeling at the immune synapse, where B cells display defective spreading responses and distribution of key signaling molecules at the synaptic membrane. Overall, our results reveal a new role for the proteasome in regulating the immune synapse of B cells, where the intracellular compartmentalization of proteasome activity controls cytoskeleton remodeling between the centrosome and synapse, with functional repercussions in antigen extraction and presentation.
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Affiliation(s)
- Jorge Ibañez-Vega
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Felipe Del Valle Batalla
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan José Saez
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Andrea Soza
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Facultad de Ciencias, Universidad San Sebastián, Santiago, Chile
- Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Maria-Isabel Yuseff
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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19
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Hapak SM, Rothlin CV, Ghosh S. PAR3-PAR6-atypical PKC polarity complex proteins in neuronal polarization. Cell Mol Life Sci 2018; 75:2735-2761. [PMID: 29696344 PMCID: PMC11105418 DOI: 10.1007/s00018-018-2828-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 04/03/2018] [Accepted: 04/23/2018] [Indexed: 01/01/2023]
Abstract
Polarity is a fundamental feature of cells. Protein complexes, including the PAR3-PAR6-aPKC complex, have conserved roles in establishing polarity across a number of eukaryotic cell types. In neurons, polarity is evident as distinct axonal versus dendritic domains. The PAR3, PAR6, and aPKC proteins also play important roles in neuronal polarization. During this process, either aPKC kinase activity, the assembly of the PAR3-PAR6-aPKC complex or the localization of these proteins is regulated downstream of a number of signaling pathways. In turn, the PAR3, PAR6, and aPKC proteins control various effector molecules to establish neuronal polarity. Herein, we discuss the many signaling mechanisms and effector functions that have been linked to PAR3, PAR6, and aPKC during the establishment of neuronal polarity.
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Affiliation(s)
- Sophie M Hapak
- Department of Medicine, School of Medicine, University of Minnesota, 401 East River Parkway, Minneapolis, MN, 55455, USA.
| | - Carla V Rothlin
- Department of Immunobiology, School of Medicine, Yale University, 300 Cedar Street, New Haven, CT, 06520, USA
- Department of Pharmacology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT, 06520, USA
| | - Sourav Ghosh
- Department of Neurology, School of Medicine, Yale University, 300 George Street, New Haven, CT, 06511, USA
- Department of Pharmacology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT, 06520, USA
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20
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Neuronal polarization: From spatiotemporal signaling to cytoskeletal dynamics. Mol Cell Neurosci 2017; 84:11-28. [PMID: 28363876 DOI: 10.1016/j.mcn.2017.03.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/24/2017] [Accepted: 03/26/2017] [Indexed: 12/20/2022] Open
Abstract
Neuronal polarization establishes distinct molecular structures to generate a single axon and multiple dendrites. Studies over the past years indicate that this efficient separation is brought about by a network of feedback loops. Axonal growth seems to play a major role in fueling those feedback loops and thereby stabilizing neuronal polarity. Indeed, various effectors involved in feedback loops are pivotal for axonal growth by ultimately acting on the actin and microtubule cytoskeleton. These effectors have key roles in interconnecting actin and microtubule dynamics - a mechanism crucial to commanding the growth of axons. We propose a model connecting signaling with cytoskeletal dynamics and neurite growth to better describe the underlying processes involved in neuronal polarization. We will discuss the current views on feedback loops and highlight the current limits of our understanding.
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21
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Ko HR, Kwon IS, Hwang I, Jin EJ, Shin JH, Brennan-Minnella AM, Swanson R, Cho SW, Lee KH, Ahn JY. Akt1-Inhibitor of DNA binding2 is essential for growth cone formation and axon growth and promotes central nervous system axon regeneration. eLife 2016; 5. [PMID: 27938661 PMCID: PMC5153247 DOI: 10.7554/elife.20799] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 11/28/2016] [Indexed: 02/02/2023] Open
Abstract
Mechanistic studies of axon growth during development are beneficial to the search for neuron-intrinsic regulators of axon regeneration. Here, we discovered that, in the developing neuron from rat, Akt signaling regulates axon growth and growth cone formation through phosphorylation of serine 14 (S14) on Inhibitor of DNA binding 2 (Id2). This enhances Id2 protein stability by means of escape from proteasomal degradation, and steers its localization to the growth cone, where Id2 interacts with radixin that is critical for growth cone formation. Knockdown of Id2, or abrogation of Id2 phosphorylation at S14, greatly impairs axon growth and the architecture of growth cone. Intriguingly, reinstatement of Akt/Id2 signaling after injury in mouse hippocampal slices redeemed growth promoting ability, leading to obvious axon regeneration. Our results suggest that Akt/Id2 signaling is a key module for growth cone formation and axon growth, and its augmentation plays a potential role in CNS axonal regeneration. DOI:http://dx.doi.org/10.7554/eLife.20799.001
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Affiliation(s)
- Hyo Rim Ko
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Il-Sun Kwon
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Inwoo Hwang
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Eun-Ju Jin
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Joo-Ho Shin
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Angela M Brennan-Minnella
- The Department of Neurology, University of California, San Francisco Medical Center, San Francisco, United States
| | - Raymond Swanson
- The Department of Neurology, University of California, San Francisco Medical Center, San Francisco, United States
| | - Sung-Woo Cho
- Department of Biochemistry and Molecular Biology, University of Ulsan, College of Medicine, Seoul, Republic of Korea
| | - Kyung-Hoon Lee
- Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Department of Anatomy, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Jee-Yin Ahn
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
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22
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Diez H, Benitez MJ, Fernandez S, Torres-Aleman I, Garrido JJ, Wandosell F. Class I PI3-kinase or Akt inhibition do not impair axonal polarization, but slow down axonal elongation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2574-2583. [DOI: 10.1016/j.bbamcr.2016.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 07/05/2016] [Accepted: 07/08/2016] [Indexed: 11/17/2022]
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23
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Zhang D, Zhang Y, Ye M, Ding Y, Tang Z, Li M, Zhou Y, Wang C. Interference with Akt signaling pathway contributes curcumin-induced adipocyte insulin resistance. Mol Cell Endocrinol 2016; 429:1-9. [PMID: 27113027 DOI: 10.1016/j.mce.2016.04.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 03/28/2016] [Accepted: 04/21/2016] [Indexed: 11/16/2022]
Abstract
Previous study has shown that curcumin directly or indirectly suppresses insulin signaling in 3T3-L1 adipocytes. However, the underlying mechanism remains unclear. Here we experimentally demonstrate that curcumin inhibited the ubiquitin-proteasome system (UPS) function, activated autophagy, and reduced protein levels of protein kinase B (Akt) in a dose- and time-dependent manner in 3T3-L1 adipocytes, accompanied with attenuation of insulin-stimulated Akt phosphorylation, plasma membrane translocation of glucose transporter type 4 (GLUT4), and glucose uptake. These in vitro inhibitory effects of curcumin on Akt protein expression and insulin action were reversed by pharmacological and genetic inhibition of autophagy but not by inhibition of the UPS and caspases. In addition, Akt reduction in adipose tissues of mice treated with curcumin could be recovered by administration of autophagy inhibitor bafilomycin A1 (BFA). This new finding provides a novel mechanism by which curcumin induces insulin resistance in adipocytes.
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Affiliation(s)
- Deling Zhang
- Department of Pathology & Pathophysiology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Yemin Zhang
- Department of Pathology & Pathophysiology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Mao Ye
- Department of Endocrinology, The Central Hospital of Enshi Autonomous Prefecture, Enshi 445000, China
| | - Youming Ding
- Department of Hepatobiliary & Laparascopic Surgery, Wuhan University Renmin Hospital, Wuhan 430060, China
| | - Zhao Tang
- Department of Pathology & Pathophysiology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Mingxin Li
- Department of Pathology & Pathophysiology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Yu Zhou
- Department of Hepatobiliary & Laparascopic Surgery, Wuhan University Renmin Hospital, Wuhan 430060, China
| | - Changhua Wang
- Department of Pathology & Pathophysiology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China.
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24
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Hsu MT, Guo CL, Liou AY, Chang TY, Ng MC, Florea BI, Overkleeft HS, Wu YL, Liao JC, Cheng PL. Stage-Dependent Axon Transport of Proteasomes Contributes to Axon Development. Dev Cell 2016; 35:418-31. [PMID: 26609957 DOI: 10.1016/j.devcel.2015.10.018] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 09/22/2015] [Accepted: 10/22/2015] [Indexed: 01/26/2023]
Abstract
Axon extension at the growing tip requires elevated local protein supply, with a capability sustainable over long axons in varying environments. The exact mechanisms, however, remain elusive. Here we report that axon-promoting factors elicited a retrograde transport-dependent removal of proteasomes from nascent axon terminals, thereby increasing protein stability at axon tips. Such an effect occurred through phosphorylation of a dynein-interacting proteasome adaptor protein Ecm29. During the transition from immature neurites to nascent axons in cultured hippocampal neurons, live-cell imaging revealed a significant increase of the retrograde axonal transport of fluorescently labeled 20S proteasomes. This retrograde proteasome transport depended on neuron stage and increased with axon lengths. Blockade of retrograde transport caused accumulation of proteasomes, reduction of axon growth, and attenuation of growth-associated Par6 at the axon tip of newly polarized neurons. Our results delineate a regulatory mechanism that controls proteasome abundance via preferential transport required for axon development in newborn neurons.
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Affiliation(s)
- Meng-Tsung Hsu
- Institute of Molecular Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Chin-Lin Guo
- Institute of Physics, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Angela Y Liou
- Institute of Molecular Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Ting-Ya Chang
- Institute of Molecular Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Ming-Chong Ng
- Institute of Molecular Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Bogdan I Florea
- Leiden Institute of Chemistry, Leiden University, Rapenburg 70, 2311 EZ Leiden, the Netherlands
| | - Herman S Overkleeft
- Leiden Institute of Chemistry, Leiden University, Rapenburg 70, 2311 EZ Leiden, the Netherlands
| | - Yen-Lin Wu
- Institute of Molecular Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Jung-Chi Liao
- Institute of Atomic and Molecular Sciences, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Pei-Lin Cheng
- Institute of Molecular Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan.
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25
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Guan F, Ding Y, Zhang Y, Zhou Y, Li M, Wang C. Curcumin Suppresses Proliferation and Migration of MDA-MB-231 Breast Cancer Cells through Autophagy-Dependent Akt Degradation. PLoS One 2016; 11:e0146553. [PMID: 26752181 PMCID: PMC4708990 DOI: 10.1371/journal.pone.0146553] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 12/19/2015] [Indexed: 12/25/2022] Open
Abstract
Previous studies have evidenced that the anticancer potential of curcumin (diferuloylmethane), a main yellow bioactive compound from plant turmeric was mediated by interfering with PI3K/Akt signaling. However, the underlying molecular mechanism is still poorly understood. This study experimentally revealed that curcumin treatment reduced Akt protein expression in a dose- and time-dependent manner in MDA-MB-231 breast cancer cells, along with an activation of autophagy and suppression of ubiquitin-proteasome system (UPS) function. The curcumin-reduced Akt expression, cell proliferation, and migration were prevented by genetic and pharmacological inhibition of autophagy but not by UPS inhibition. Additionally, inactivation of AMPK by its specific inhibitor compound C or by target shRNA-mediated silencing attenuated curcumin-activated autophagy. Thus, these results indicate that curcumin-stimulated AMPK activity induces activation of the autophagy-lysosomal protein degradation pathway leading to Akt degradation and the subsequent suppression of proliferation and migration in breast cancer cell.
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Affiliation(s)
- Feng Guan
- Department of Pathophysiology, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, China
| | - Youming Ding
- Department of Hepatobiliary & Laparascopic Surgery, Wuhan University Renmin Hospital, Wuhan, 430060, China
| | - Yemin Zhang
- Department of Pathophysiology, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, China
| | - Yu Zhou
- Department of Hepatobiliary & Laparascopic Surgery, Wuhan University Renmin Hospital, Wuhan, 430060, China
| | - Mingxin Li
- Department of Pathophysiology, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, China
| | - Changhua Wang
- Department of Pathophysiology, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, China
- * E-mail:
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26
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Lalli G. Regulation of neuronal polarity. Exp Cell Res 2014; 328:267-75. [PMID: 25107381 DOI: 10.1016/j.yexcr.2014.07.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/24/2014] [Accepted: 07/26/2014] [Indexed: 12/28/2022]
Abstract
The distinctive polarized morphology of neuronal cells is essential for the proper wiring of the nervous system. The rodent hippocampal neuron culture established about three decades ago has provided an amenable in vitro system to uncover the molecular mechanisms underlying neuronal polarization, a process relying on highly regulated cytoskeletal dynamics, membrane traffic and localized protein degradation. More recent research in vivo has highlighted the importance of the extracellular environment and cell-cell interactions in neuronal polarity. Here, I will review some key signaling pathways regulating neuronal polarization and provide some insights on the complexity of this process gained from in vivo studies.
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Affiliation(s)
- Giovanna Lalli
- Wolfson Centre for Age-Related Diseases, King׳s College London, Guy׳s Campus, London SE1 1UL, UK.
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27
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Naoki H, Ishii S. Mathematical modeling of neuronal polarization during development. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 123:127-41. [PMID: 24560143 DOI: 10.1016/b978-0-12-397897-4.00003-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
During development of the brain, morphogenesis of neurons is dynamically organized from a simple rounded shape to a highly polarized morphology consisting of soma, one axon, and dendrites, which is a basis for establishing the unidirectional transfer of electric signals between neurons. The mechanism of such polarization is thought to be "local activation-global inhibition"; however, globally diffusing inhibitor molecules have not been identified. In this chapter, we present a theoretical modeling approach of such neuronal development. We first summarize biological research on neuronal polarization and then develop a biophysical model. Through mathematical analysis, principles of local activation-global inhibition are illustrated based on active transport, protein degradation, and neurite growth, but not on globally diffusing inhibitor.
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Affiliation(s)
- Honda Naoki
- Imaging Platform for Spatio-Temporal Information, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | - Shin Ishii
- Graduate School of Informatics, Kyoto University, Uji, Kyoto, Japan
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28
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Benitez MJ, Sanchez-Ponce D, Garrido JJ, Wandosell F. Hsp90 activity is necessary to acquire a proper neuronal polarization. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:245-52. [PMID: 24286867 DOI: 10.1016/j.bbamcr.2013.11.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 10/29/2013] [Accepted: 11/18/2013] [Indexed: 11/18/2022]
Abstract
Chaperones are critical for the folding and regulation of a wide array of cellular proteins. Heat Shock Proteins (Hsps) are the most representative group of chaperones. Hsp90 represents up to 1-2% of soluble protein. Although the Hsp90 role is being studied in neurodegenerative diseases, its role in neuronal differentiation remains mostly unknown. Since neuronal polarity mechanisms depend on local stability and degradation, we asked whether Hsp90 could be a regulator of axonal polarity and growth. Thus, we studied the role of Hsp90 activity in a well established model of cultured hippocampal neurons using an Hsp90 specific inhibitor, 17-AAG. Our present data shows that Hsp90 inhibition at different developmental stages disturbs neuronal polarity formation or axonal elongation. Hsp90 inhibition during the first 3h in culture promotes multiple axon morphology, while this inhibition after 3h slows down axonal elongation. Hsp90 inhibition was accompanied by decreased Akt and GSK3 expression, as well as, a reduced Akt activity. In parallel, we detected an alteration of kinesin-1 subcellular distribution. Moreover, these effects were seconded by changes in Hsp70/Hsc70 subcellular localization that seem to compensate the lack of Hsp90 activity. In conclusion, our data strongly suggests that Hsp90 activity is necessary to control the expression, activity or location of specific kinases and motor proteins during the axon specification and axon elongation processes. Even more, our data demonstrate the existence of a "time-window" for axon specification in this model of cultured neurons after which the inhibition of Hsp90 only affects axonal elongation mechanisms.
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Affiliation(s)
- M J Benitez
- Centro de Biología Molecular "Severo Ochoa", CSIC-UAM, Univ. Autonoma de Madrid, 28049 Madrid, Spain; Dpto Química Física Aplicada, Univ. Autónoma de Madrid, 28049 Madrid, Spain
| | - D Sanchez-Ponce
- Instituto Cajal, CSIC, Department of Molecular, Cellular and Developmental Neurobiology, Madrid 28002, Spain
| | - J J Garrido
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Instituto Cajal, CSIC, Department of Molecular, Cellular and Developmental Neurobiology, Madrid 28002, Spain.
| | - F Wandosell
- Centro de Biología Molecular "Severo Ochoa", CSIC-UAM, Univ. Autonoma de Madrid, 28049 Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
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29
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Dajas-Bailador F, Bantounas I, Jones EV, Whitmarsh AJ. Regulation of axon growth by the JIP1-AKT axis. J Cell Sci 2013; 127:230-9. [PMID: 24198394 DOI: 10.1242/jcs.137208] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The polarisation of developing neurons to form axons and dendrites is required for the establishment of neuronal connections leading to proper brain function. The protein kinase AKT and the MAP kinase scaffold protein JNK-interacting protein-1 (JIP1) are important regulators of axon formation. Here we report that JIP1 and AKT colocalise in axonal growth cones of cortical neurons and collaborate to promote axon growth. The loss of AKT protein from the growth cone results in the degradation of JIP1 by the proteasome, and the loss of JIP1 promotes a similar fate for AKT. Reduced protein levels of both JIP1 and AKT in the growth cone can be induced by glutamate and this coincides with reduced axon growth, which can be rescued by a stabilized mutant of JIP1 that rescues AKT protein levels. Taken together, our data reveal a collaborative relationship between JIP1 and AKT that is required for axon growth and can be regulated by changes in neuronal activity.
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Affiliation(s)
- Federico Dajas-Bailador
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
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30
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Alan JK, Struckhoff EC, Lundquist EA. Multiple cytoskeletal pathways and PI3K signaling mediate CDC-42-induced neuronal protrusion in C. elegans. Small GTPases 2013; 4:208-20. [PMID: 24149939 PMCID: PMC4011816 DOI: 10.4161/sgtp.26602] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 09/23/2013] [Accepted: 09/25/2013] [Indexed: 12/30/2022] Open
Abstract
Rho GTPases are key regulators of cellular protrusion and are involved in many developmental events including axon guidance during nervous system development. Rho GTPase pathways display functional redundancy in developmental events, including axon guidance. Therefore, their roles can often be masked when using simple loss-of-function genetic approaches. As a complement to loss-of-function genetics, we constructed a constitutively activated CDC-42(G12V) expressed in C. elegans neurons. CDC-42(G12V) drove the formation of ectopic lamellipodial and filopodial protrusions in the PDE neurons, which resembled protrusions normally found on migrating growth cones of axons. We then used a candidate gene approach to identify molecules that mediate CDC-42(G12V)-induced ectopic protrusions by determining if loss of function of the genes could suppress CDC-42(G12V). Using this approach, we identified 3 cytoskeletal pathways previously implicated in axon guidance, the Arp2/3 complex, UNC-115/abLIM, and UNC-43/Ena. We also identified the Nck-interacting kinase MIG-15/NIK and p21-activated kinases (PAKs), also implicated in axon guidance. Finally, PI3K signaling was required, specifically the Rictor/mTORC2 branch but not the mTORC1 branch that has been implicated in other aspects of PI3K signaling including stress and aging. Our results indicate that multiple pathways can mediate CDC-42-induced neuronal protrusions that might be relevant to growth cone protrusions during axon pathfinding. Each of these pathways involves Rac GTPases, which might serve to integrate the pathways and coordinate the multiple CDC-42 pathways. These pathways might be relevant to developmental events such as axon pathfinding as well as disease states such as metastatic melanoma.
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Affiliation(s)
| | - Eric C Struckhoff
- Department of Molecular Biosciences; University of Kansas; Lawrence, KS USA
| | - Erik A Lundquist
- Department of Molecular Biosciences; University of Kansas; Lawrence, KS USA
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31
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Hammond VE, Gunnersen JM, Goh CP, Low LH, Hyakumura T, Tang MM, Britto JM, Putz U, Howitt JA, Tan SS. Ndfip1 is required for the development of pyramidal neuron dendrites and spines in the neocortex. ACTA ACUST UNITED AC 2013; 24:3289-300. [PMID: 23897647 DOI: 10.1093/cercor/bht191] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Ubiquitin ligases of the Nedd4 family are important for axon and dendrite development, but little is known about their adaptor, Nedd4 family-interacting protein 1 (Ndfip1), that is responsible for their enzymatic activation. To study the function of Ndfip1 in cortical development, we generated a conditional knock-out (conditional KO) in neurons. The Ndfip1 conditional KO mice were viable; however, cortical neurons in the adult brain exhibited atrophic characteristics, including stunted dendritic arbors, blebbing of dendrites, and fewer dendritic spines. In electron micrographs, these neurons appeared shrunken with compacted somata and involutions of the nuclear membrane. In culture, Ndfip1 KO neurons exhibited exuberant sprouting suggesting loss of developmental control. Biochemical analysis of postsynaptic density (PSD) fractions from Ndfip1 KO cortical and hippocampal neurons showed that the postsynaptic proteins (Arc and PSD-95) were reduced compared with wild-type controls. In addition, the PI3 kinase/Akt signaling pathway was altered. These results indicate that Ndfip1, through its Nedd4 effectors, is important for the development of dendrites and dendritic spines in the cortex.
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Affiliation(s)
| | - Jenny M Gunnersen
- Florey Institute of Neuroscience and Mental Health and Department of Anatomy and Neuroscience, The University of Melbourne, Victoria 3010, Australia
| | - Choo-Peng Goh
- Florey Institute of Neuroscience and Mental Health and
| | - Ley-Hian Low
- Florey Institute of Neuroscience and Mental Health and
| | | | | | | | - Ulrich Putz
- Florey Institute of Neuroscience and Mental Health and
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32
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Role of phosphatidylinositol 3,4,5-trisphosphate in cell signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 991:105-39. [PMID: 23775693 DOI: 10.1007/978-94-007-6331-9_7] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Many lipids present in cellular membranes are phosphorylated as part of signaling cascades and participate in the recruitment, localization, and activation of downstream protein effectors. Phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P3) is one of the most important second messengers and is capable of interacting with a variety of proteins through specific PtdIns(3,4,5)P3 binding domains. Localization and activation of these effector proteins controls a myriad of cellular functions including cell survival, proliferation, cytoskeletal rearrangement, and gene expression. Aberrations in the production and metabolism of PtdIns(3,4,5)P3 have been implicated in many human diseases including cancer, diabetes, inflammation, and heart disease. This chapter provides an overview of the role of PtdIns(3,4,5)P3 in cellular regulation and the implications of PtdIns(3,4,5)P3 dysregulation in human diseases. Additionally, recent attempts at targeting PtdIns(3,4,5)P3 signaling via small molecule inhibitors are summarized.
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33
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Markwardt ML, Nkobena A, Ding SY, Rizzo MA. Association with nitric oxide synthase on insulin secretory granules regulates glucokinase protein levels. Mol Endocrinol 2012; 26:1617-29. [PMID: 22771492 PMCID: PMC3434526 DOI: 10.1210/me.2012-1183] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 06/19/2012] [Indexed: 11/19/2022] Open
Abstract
Glucokinase (GCK) association with insulin-secretory granules is controlled by interaction with nitric oxide synthase (NOS) and is reversed by GCK S-nitrosylation. Nonetheless, the function of GCK sequestration on secretory granules is unknown. Here we report that the S-nitrosylation blocking V367M mutation prevents GCK accumulation on secretory granules by inhibiting association with NOS. Expression of this mutant is reduced compared with a second S-nitrosylation blocking GCK mutant (C371S) that accumulates to secretory granules and is expressed at levels greater than wild type. Even so, the rate of degradation for wild type and mutant GCK proteins were not significantly different from one another, and neither mutation disrupted the ability of GCK to be ubiquitinated. Furthermore, gene silencing of NOS reduced endogenous GCK content but did not affect β-actin content. Treatment of GCK(C371S) expressing cells with short interfering RNA specific for NOS also blocked accumulation of this protein to secretory granules and reduced expression levels to that of GCK(V367M). Conversely, cotransfection of catalytically inactive NOS increased GCK-mCherry levels. Expression of GCK(C371S) in βTC3 cells enhanced glucose metabolism compared with untransfected cells and cells expressing wild type GCK, even though this mutant has slightly reduced enzymatic activity in vitro. Finally, molecular dynamics simulations revealed that V367M induces conformational changes in GCK that are similar to S-nitrosylated GCK, thereby suggesting a mechanism for V367M-inhibition of NOS association. Our findings suggest that sequestration of GCK on secretory granules regulates cellular GCK protein content, and thus cellular GCK activity, by acting as a storage pool for GCK proteins.
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Affiliation(s)
- Michele L Markwardt
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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34
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Wang X, Ye B. Transcriptional regulators that differentially control dendrite and axon development. FRONTIERS IN BIOLOGY 2012; 7:292-296. [PMID: 39219713 PMCID: PMC11364217 DOI: 10.1007/s11515-012-1234-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Neurons are the basic units establishing connectivity in the nervous system. As a signature feature, neurons form polarized structures: dendrites and axons, which integrate either sensory stimuli or inputs from upstream neurons and send outputs to target cells, respectively. The separation of dendritic and axonal compartments is achieved in two steps during development: 1) dendrite and axon specification: how neurites are initially specified as dendrites and axons; and 2) dendrite and axon commitment: how dendrites and axons are committed to distinct compartmental fates and architectures. In order to understand neural circuit assembly and to correct erroneous dendrite or axon growth in a compartment-specific manner, it is essential to understand the regulatory mechanisms underlying dendrite and axon commitment. Compared to extensive studies on dendrite and axon specification, little is known about the molecular mechanisms exclusively dedicated to dendrite or axon commitment. Recent studies have uncovered the requirement of transcriptional regulation in this process. Here, we review the studies on transcriptional regulators: Dar1, p300-SnoN, NeuroD, which have been shown to separate dendrite- and axon-specific growth of the same neuron type after compartmental fates are specified.
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Affiliation(s)
- Xin Wang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Bing Ye
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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35
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Affiliation(s)
- Pei-lin Cheng
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan;
| | - Mu-ming Poo
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California, 94720, USA;
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36
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Diez H, Garrido JJ, Wandosell F. Specific roles of Akt iso forms in apoptosis and axon growth regulation in neurons. PLoS One 2012; 7:e32715. [PMID: 22509246 PMCID: PMC3324480 DOI: 10.1371/journal.pone.0032715] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 01/30/2012] [Indexed: 01/31/2023] Open
Abstract
Akt is a member of the AGC kinase family and consists of three isoforms. As one of the major regulators of the class I PI3 kinase pathway, it has a key role in the control of cell metabolism, growth, and survival. Although it has been extensively studied in the nervous system, we have only a faint knowledge of the specific role of each isoform in differentiated neurons. Here, we have used both cortical and hippocampal neuronal cultures to analyse their function. We characterized the expression and function of Akt isoforms, and some of their substrates along different stages of neuronal development using a specific shRNA approach to elucidate the involvement of each isoform in neuron viability, axon development, and cell signalling. Our results suggest that three Akt isoforms show substantial compensation in many processes. However, the disruption of Akt2 and Akt3 significantly reduced neuron viability and axon length. These changes correlated with a tendency to increase in active caspase 3 and a decrease in the phosphorylation of some elements of the mTORC1 pathway. Indeed, the decrease of Akt2 and more evident the inhibition of Akt3 reduced the expression and phosphorylation of S6. All these data indicate that Akt2 and Akt3 specifically regulate some aspects of apoptosis and cell growth in cultured neurons and may contribute to the understanding of mechanisms of neuron death and pathologies that show deregulated growth.
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Affiliation(s)
- Hector Diez
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) and Centro de Biología Molecular “Severo Ochoa", CSIC-UAM, Univ. Autonoma de Madrid, Madrid, Spain
| | - Juan Jose Garrido
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) and Centro de Biología Molecular “Severo Ochoa", CSIC-UAM, Univ. Autonoma de Madrid, Madrid, Spain
- Laboratory of Neuronal Polarity, Department of Molecular, Cellular and Developmental Neurobiology, Instituto Cajal, CSIC, Madrid, Spain
| | - Francisco Wandosell
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) and Centro de Biología Molecular “Severo Ochoa", CSIC-UAM, Univ. Autonoma de Madrid, Madrid, Spain
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37
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Abstract
The serine/threonine kinase Akt functions in multiple cellular processes, including cell survival and tumor development. Studies of the mechanisms that negatively regulate Akt have focused on dephosphorylation-mediated inactivation. In this study, we identified a negative regulator of Akt, MULAN, which possesses both a RING finger domain and E3 ubiquitin ligase activity. Akt was found to directly interact with MULAN and to be ubiquitinated by MULAN in vitro and in vivo. Other molecular assays demonstrated that phosphorylated Akt is a substantive target for both interaction with MULAN and ubiquitination by MULAN. The results of the functional studies suggest that the degradation of Akt by MULAN suppresses cell proliferation and viability. These data provide insight into the Akt ubiquitination signaling network.
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Ye T, Fu AK, Ip NY. Cyclin-Dependent Kinase 5 in Axon Growth and Regeneration. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2012. [DOI: 10.1016/b978-0-12-398309-1.00006-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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39
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Kim YT, Hur EM, Snider WD, Zhou FQ. Role of GSK3 Signaling in Neuronal Morphogenesis. Front Mol Neurosci 2011; 4:48. [PMID: 22131966 PMCID: PMC3222852 DOI: 10.3389/fnmol.2011.00048] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 11/06/2011] [Indexed: 01/28/2023] Open
Abstract
Glycogen synthase kinase 3 (GSK3) is emerging as a key regulator of several aspects of neuronal morphogenesis including neuronal polarization, axon growth, and axon branching. Multiple signaling pathways have been identified that control neuronal polarization, including PI3K, Rho-GTPases, Par3/6, TSC–mTOR, and PKA–LKB1. However, how these pathways are coordinated is not clear. As GSK3 signaling exhibits crosstalk with each of these pathways it has the potential to integrate these polarity signals in the control neuronal polarization. After neurons establish polarity, GSK3 acts as an important signaling mediator in the regulation of axon extension and axon branching by transducing upstream signaling to reorganization of the axonal cytoskeleton, especially microtubules. Here we review the roles of GSK3 signaling in neuronal morphogenesis and discuss the underlying molecular mechanisms.
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Affiliation(s)
- Yun Tai Kim
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine Baltimore, MD, USA
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40
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ZNRF1 promotes Wallerian degeneration by degrading AKT to induce GSK3B-dependent CRMP2 phosphorylation. Nat Cell Biol 2011; 13:1415-23. [PMID: 22057101 DOI: 10.1038/ncb2373] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 10/05/2011] [Indexed: 02/07/2023]
Abstract
Wallerian degeneration is observed in many neurological disorders, and it is therefore important to elucidate the axonal degeneration mechanism to prevent, and further develop treatment for, such diseases. The ubiquitin-proteasome system (UPS) has been implicated in Wallerian degeneration, but the underlying molecular mechanism remains unclear. Here we show that ZNRF1, an E3 ligase, promotes Wallerian degeneration by targeting AKT to degrade through the UPS. AKT phosphorylates glycogen synthase kinase-3β (GSK3B), and thereby inactivates it in axons. AKT overexpression significantly delays axonal degeneration. Overexpression of the active (non-phosphorylated) form of GSK3B induces CRMP2 phosphorylation, which is required for the microtubule reorganization observed in the degenerating axon. The inhibition of GSK3B and the overexpression of non-phosphorylated CRMP2 both protected axons from Wallerian degeneration. These findings indicate that the ZNRF1-AKT-GSK3B-CRMP2 pathway plays an important role in controlling Wallerian degeneration.
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41
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Kim SY, Lee JH, Huh JW, Ro JY, Oh YM, Lee SD, An S, Lee YS. Cigarette smoke induces Akt protein degradation by the ubiquitin-proteasome system. J Biol Chem 2011; 286:31932-43. [PMID: 21778238 PMCID: PMC3173210 DOI: 10.1074/jbc.m111.267633] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 07/13/2011] [Indexed: 11/06/2022] Open
Abstract
Emphysema is one of the characteristic features of chronic obstructive pulmonary disease, which is caused mainly by cigarette smoking. Recent data have suggested that apoptosis and cell cycle arrest may contribute to the development of emphysema. In this study, we addressed the question of whether and how cigarette smoke affected Akt, which plays a critical role in cell survival and proliferation. In normal human lung fibroblasts, cigarette smoke extract (CSE) caused cell death, accompanying degradation of total and phosphorylated Akt (p-Akt), which was inhibited by MG132. CSE exposure resulted in preferential ubiquitination of the active Akt (myristoylated), rather than the inactive (T308A/S473A double mutant) Akt. Consistent with cytotoxicity, CSE induced a progressive decrease of phosphorylated human homolog of mouse double minute homolog 2 (p-HDM2) and phosphorylated apoptosis signal regulating kinase 1 (p-ASK1) with concomitant elevation of p53, p21, and phosphorylated p38 MAPK. Forced expression of the active Akt reduced both CSE-induced cytotoxicity and alteration in HDM2/p53/p21 and ASK1/p38 MAPK, compared with the inactive Akt. Of note, CSE induced expression of the tetratrico-peptide repeat domain 3 (TTC3), known as a ubiquitin ligase for active Akt. TTC3 siRNAs suppressed not only CSE-induced Akt degradation but also CSE-induced cytotoxicity. Accordingly, rat lungs exposed to cigarette smoke for 3 months showed elevated TTC3 expression and reduced Akt and p-Akt. Taken together, these data suggest that cigarette smoke induces cytotoxicity, partly through Akt degradation via the ubiquitin-proteasome system, in which TTC3 acts as a ubiquitin ligase for active Akt.
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Affiliation(s)
- Sun-Yong Kim
- From the Division of Pharmacology, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute, Suwon 440-746
| | - Ji-Hyun Lee
- the Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, College of Medicine, Pochon CHA University, Seongnam 463-712
| | - Jin Won Huh
- the Department of Pulmonary and Critical Care Medicine, Asthma Center, and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, and
| | - Jai Youl Ro
- From the Division of Pharmacology, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute, Suwon 440-746
| | - Yeon-Mock Oh
- the Department of Pulmonary and Critical Care Medicine, Asthma Center, and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, and
| | - Sang-Do Lee
- the Department of Pulmonary and Critical Care Medicine, Asthma Center, and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, and
| | - Sungkwan An
- the Functional Genoproteome Research Centre, Konkuk University, Seoul 143-701, Republic of Korea
| | - Yun-Song Lee
- From the Division of Pharmacology, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute, Suwon 440-746
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Abstract
A hallmark of neurons is their ability to polarize with dendrite and axon specification to allow the proper flow of information through the nervous system. Over the past decade, extensive research has been performed in an attempt to understand the molecular and cellular machinery mediating this neuronal polarization process. It has become evident that many of the critical regulators involved in establishing neuronal polarity are evolutionarily conserved proteins that had previously been implicated in controlling the polarization of other cell types. At the forefront of this research are the partition defective (Par) proteins. In this review,we will provide a commentary on the progress of work regarding the central importance of Parproteins in the establishment of neuronal polarity.
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Affiliation(s)
- Ryan Insolera
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
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43
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Rehni AK, Singh TG, Behl N, Arora S. Possible involvement of ubiquitin proteasome system and other proteases in acute and delayed aspects of ischemic preconditioning of brain in mice. Biol Pharm Bull 2011; 33:1953-7. [PMID: 21139232 DOI: 10.1248/bpb.33.1953] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study has been designed to investigate the potential role of ubiquitin proteasome system and other proteases in acute as well as delayed aspects of ischemic preconditioning induced reversal of ischemia-reperfusion injury in mouse brain. Bilateral carotid artery occlusion of 17 min followed by reperfusion for 24 h was employed in present study to produce ischemia and reperfusion induced cerebral injury in mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Memory was evaluated using elevated plus-maze test. Rota rod test was employed to assess motor incoordination. Bilateral carotid artery occlusion followed by reperfusion produced cerebral infarction and impaired memory and motor co-ordination. Three preceding episodes of bilateral carotid artery occlusion for 1 min and reperfusion of 1 min (ischemic preconditioning) both immediately before (for acute preconditioning) and 24 h before (for delayed preconditioning) global cerebral ischemia prevented markedly ischemia-reperfusion-induced cerebral injury as measured in terms of infarct size, loss of memory and motor coordination. Z-Leu-Leu-Phe-Chinese hamster ovary (CHO) (2 mg/kg, intraperitoneally (i.p.)), an inhibitor of ubiquitin proteasome system and other proteases attenuated the neuroprotective effect of both the acute as well as delayed ischemic preconditioning. It is concluded that the neuroprotective effect of both the acute as well as delayed phases of ischemic preconditioning may be due to the activation of ubiquitin proteasome system and other proteases.
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44
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Zhang L, Sun S, Zhou J, Liu J, Lv JH, Yu XQ, Li C, Gong L, Yan Q, Deng M, Xiao L, Ma H, Liu JP, Peng YL, Wang D, Liao GP, Zou LJ, Liu WB, Xiao YM, Li DWC. Knockdown of Akt1 promotes Akt2 upregulation and resistance to oxidative-stress-induced apoptosis through control of multiple signaling pathways. Antioxid Redox Signal 2011; 15:1-17. [PMID: 21303257 PMCID: PMC3110099 DOI: 10.1089/ars.2010.3560] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The Akt signaling pathway plays a key role in promoting the survival of various types of cells from stress-induced apoptosis, and different members of the Akt family display distinct physiological roles. Previous studies have shown that in response to UV irradiation, Akt2 is sensitized to counteract the induced apoptosis. However, in response to oxidative stress such as hydrogen peroxide, it remains to be elucidated what member of the Akt family would be activated to initiate the signaling cascades leading to resistance of the induced apoptosis. In the present study, we present the first evidence that knockdown of Akt1 enhances cell survival under exposure to 50 μM H(2)O(2). This survival is derived from selective upregulation and activation of Akt2 but not Akt3, which initiates 3 major signaling cascades. First, murine double minute 2 (MDM2) is hyperphosphorylated, which promotes p53 degradation and attenuates its Ser-15 phosphorylation, significantly attenuating Bcl-2 homologous antagonist killer (Bak) upregulation. Second, Akt2 activation inactivates glycogen synthase kinase 3 beta (GSK-3β) to promote stability of myeloid leukemia cell differentiation protein 1 (MCL-1). Finally, Akt2 activation promotes phosphorylation of FOXO3A toward cytosolic export and thus downregulates Bim expression. Overexpression of Bim enhances H(2)O(2)-induced apoptosis. Together, our results demonstrate that among the Akt family members, Akt2 is an essential kinase in counteracting oxidative-stress-induced apoptosis through multiple signaling pathways.
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Affiliation(s)
- Lan Zhang
- University of Nebraska Medical Center, Omaha, 68198-5870, USA
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Litterman N, Ikeuchi Y, Gallardo G, O'Connell BC, Sowa ME, Gygi SP, Harper JW, Bonni A. An OBSL1-Cul7Fbxw8 ubiquitin ligase signaling mechanism regulates Golgi morphology and dendrite patterning. PLoS Biol 2011; 9:e1001060. [PMID: 21572988 PMCID: PMC3091842 DOI: 10.1371/journal.pbio.1001060] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 03/25/2011] [Indexed: 12/22/2022] Open
Abstract
The elaboration of dendrites in neurons requires secretory trafficking through the Golgi apparatus, but the mechanisms that govern Golgi function in neuronal morphogenesis in the brain have remained largely unexplored. Here, we report that the E3 ubiquitin ligase Cul7Fbxw8 localizes to the Golgi complex in mammalian brain neurons. Inhibition of Cul7Fbxw8 by independent approaches including Fbxw8 knockdown reveals that Cul7Fbxw8 is selectively required for the growth and elaboration of dendrites but not axons in primary neurons and in the developing rat cerebellum in vivo. Inhibition of Cul7Fbxw8 also dramatically impairs the morphology of the Golgi complex, leading to deficient secretory trafficking in neurons. Using an immunoprecipitation/mass spectrometry screening approach, we also uncover the cytoskeletal adaptor protein OBSL1 as a critical regulator of Cul7Fbxw8 in Golgi morphogenesis and dendrite elaboration. OBSL1 forms a physical complex with the scaffold protein Cul7 and thereby localizes Cul7 at the Golgi apparatus. Accordingly, OBSL1 is required for the morphogenesis of the Golgi apparatus and the elaboration of dendrites. Finally, we identify the Golgi protein Grasp65 as a novel and physiologically relevant substrate of Cul7Fbxw8 in the control of Golgi and dendrite morphogenesis in neurons. Collectively, these findings define a novel OBSL1-regulated Cul7Fbxw8 ubiquitin signaling mechanism that orchestrates the morphogenesis of the Golgi apparatus and patterning of dendrites, with fundamental implications for our understanding of brain development. The growth and elaboration of dendrites is an essential step in the establishment of neuronal circuits in the brain. Because dendrites house the receptive components of neurotransmission and actively integrate synaptic inputs, variations in dendrite architecture have important consequences for information processing. The development of dendrites relies on secretory trafficking through the Golgi apparatus. In this study, we have identified an E3 ubiquitin ligase, Cul7Fbxw8, that localizes to the Golgi apparatus in neurons. E3 ubiquitin ligases regulate the abundance of target proteins by directing ubiquitin-dependent proteolysis of specific targets. We have found that Cul7Fbxw8 operates at the Golgi apparatus to control Golgi integrity and dendrite patterning. We have also identified the cytoskeletal adaptor protein OBSL1 as an important regulator of Cul7Fbxw8 function in neurons. OBSL1 promotes the function of Cul7Fbxw8 by localizing Cul7 at the Golgi apparatus. Finally, we have found that Cul7Fbxw8 induces the ubiquitination and degradation of the Golgi protein Grasp65 to control Golgi morphology and dendrite elaboration. We conclude that the signaling cascade from OBSL1 to Cul7Fbxw8 to Grasp65 is an important means of regulating Golgi morphology and consequently the shape and size of dendrite arbors in neurons.
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Affiliation(s)
- Nadia Litterman
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yoshiho Ikeuchi
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Gilbert Gallardo
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Brenda C. O'Connell
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mathew E. Sowa
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Steven P. Gygi
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - J. Wade Harper
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Azad Bonni
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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Namba T, Nakamuta S, Funahashi Y, Kaibuchi K. The role of selective transport in neuronal polarization. Dev Neurobiol 2011; 71:445-57. [DOI: 10.1002/dneu.20876] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Naoki H, Nakamuta S, Kaibuchi K, Ishii S. Flexible search for single-axon morphology during neuronal spontaneous polarization. PLoS One 2011; 6:e19034. [PMID: 21559492 PMCID: PMC3084731 DOI: 10.1371/journal.pone.0019034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 03/15/2011] [Indexed: 11/21/2022] Open
Abstract
Polarization, a disruption of symmetry in cellular morphology, occurs spontaneously, even in symmetrical extracellular conditions. This process is regulated by intracellular chemical reactions and the active transport of proteins and it is accompanied by cellular morphological changes. To elucidate the general principles underlying polarization, we focused on developing neurons. Neuronal polarity is stably established; a neuron initially has several neurites of similar length, but only one elongates and is selected to develop into an axon. Polarization is flexibly controlled; when multiple neurites are selected, the selection is eventually reduced to yield a single axon. What is the system by which morphological information is decoded differently based on the presence of a single or multiple axons? How are stability and flexibility achieved? To answer these questions, we constructed a biophysical model with the active transport of proteins that regulate neurite growth. Our mathematical analysis and computer simulation revealed that, as neurites elongate, transported factors accumulate in the growth cone but are degraded during retrograde diffusion to the soma. Such a system effectively works as local activation-global inhibition mechanism, resulting in both stability and flexibility. Our model shows good accordance with a number of experimental observations.
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Affiliation(s)
- Honda Naoki
- Graduate School of Informatics, Kyoto University, Uji, Kyoto, Japan.
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Grabbe C, Husnjak K, Dikic I. The spatial and temporal organization of ubiquitin networks. Nat Rev Mol Cell Biol 2011; 12:295-307. [PMID: 21448225 DOI: 10.1038/nrm3099] [Citation(s) in RCA: 279] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In the past decade, the diversity of signals generated by the ubiquitin system has emerged as a dominant regulator of biological processes and propagation of information in the eukaryotic cell. A wealth of information has been gained about the crucial role of spatial and temporal regulation of ubiquitin species of different lengths and linkages in the nuclear factor-κB (NF-κB) pathway, endocytic trafficking, protein degradation and DNA repair. This spatiotemporal regulation is achieved through sophisticated mechanisms of compartmentalization and sequential series of ubiquitylation events and signal decoding, which control diverse biological processes not only in the cell but also during the development of tissues and entire organisms.
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Affiliation(s)
- Caroline Grabbe
- Department of Molecular Biology, Umeå University, Umeå, Sweden
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Cheng PL, Lu H, Shelly M, Gao H, Poo MM. Phosphorylation of E3 ligase Smurf1 switches its substrate preference in support of axon development. Neuron 2011; 69:231-43. [PMID: 21262463 DOI: 10.1016/j.neuron.2010.12.021] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2010] [Indexed: 12/19/2022]
Abstract
Ubiquitin E3 ligases serve for ubiquitination of specific substrates, and its ligase efficacy is regulated by interacting proteins or substrate modifications. Whether and how the ligases themselves are modified by cellular signaling is unclear. Here we report that protein kinase A (PKA)-dependent phosphorylation of Smad Ubiquitin Regulatory Factor 1 (Smurf1) can switch its substrate preference between two proteins of opposing actions on axon development. Extracellular factors that promote axon formation elevated Smurf1 phosphorylation at a PKA site Thr³⁰⁶, and preventing this phosphorylation reduced axon formation in cultured hippocampal neurons and impaired polarization of cortical neurons in vivo. Thr³⁰⁶-phosphorylation changed the relative affinities of Smurf1 for its substrates, leading to reduced degradation of polarity protein Par6 and increased degradation of growth-inhibiting RhoA. Thus, PKA-dependent phosphorylation of the E3 ligase could switch its substrate preference, contributing to selective protein degradation required for localized cellular function.
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Affiliation(s)
- Pei-lin Cheng
- Division of Neurobiology, Department of Molecular and Cell Biology, and Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720, USA
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50
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Abstract
The assembly of functional neuronal networks in the developing animal relies on the polarization of neurons, i.e., the formation of a single axon and multiple dendrites. Breaking the symmetry of neurons depends on cytoskeletal rearrangements. In particular, axon specification requires local dynamic instability of actin and stabilization of microtubules. The polarized cytoskeleton also provides the basis for selective trafficking and retention of cellular components in the future somatodendritic or axonal compartments. Hence, these mechanisms are not only essential to achieve neuronal polarization, but also to maintain it. Different extracellular and intracellular signals converge on the regulation of the cytoskeleton. Most notably, Rho GTPases, PI3K, Ena/VASP, cofilin and SAD kinases are major intracellular regulators of neuronal polarity. Analyzing polarity signals under physiological conditions will provide a better understanding of how neurons can be induced to repolarize under pathological conditions, i.e., to regenerate their axons after central nervous system (CNS) injury.
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Affiliation(s)
- Sabina Tahirovic
- Max Planck Institute of Neurobiology, Axonal Growth and Regeneration, Am Klopferspitz 18, 82152 Martinsried, Germany
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