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An P, Xu W, Luo J, Luo Y. Expanding TOR Complex 2 Signaling: Emerging Regulators and New Connections. Front Cell Dev Biol 2021; 9:713806. [PMID: 34395443 PMCID: PMC8363310 DOI: 10.3389/fcell.2021.713806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 07/15/2021] [Indexed: 12/16/2022] Open
Abstract
Almost three decades after its seminal discovery, our understanding of the remarkable TOR pathway continues to expand. As a TOR complex, TORC2 lies at the nexus of many signaling pathways and directs a diverse array of fundamental processes such as cell survival, proliferation, and metabolism by integrating environmental and intracellular cues. The dysregulation of TORC2 activity disrupts cellular homeostasis and leads to many pathophysiological conditions. With continued efforts at mapping the signaling landscape, the pace of discovery in TORC2 regulation has been accelerated in recent years. Consequently, emerging evidence has expanded the repertoire of upstream regulators and has revealed unexpected diversity in the modes of TORC2 regulation. Multiple environmental cues and plasma membrane proteins that fine-tune TORC2 activity are unfolding. Furthermore, TORC2 signaling is intricately intertwined with other major signaling pathways. Therefore, feedback and crosstalk regulation also extensively modulate TORC2. In this context, we provide a comprehensive overview of revolutionary concepts regarding emerging regulators of TORC2 and discuss evidence of feedback and crosstalk regulation that shed new light on TORC2 biology.
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Affiliation(s)
- Peng An
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, China
| | - Wenyi Xu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, China
| | - Junjie Luo
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, China
| | - Yongting Luo
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, China
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2
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Nam JK, Kim AR, Choi SH, Kim JH, Choi KJ, Cho S, Lee JW, Cho HJ, Kwon YW, Cho J, Kim KS, Kim J, Lee HJ, Lee TS, Bae S, Hong HJ, Lee YJ. An antibody against L1 cell adhesion molecule inhibits cardiotoxicity by regulating persistent DNA damage. Nat Commun 2021; 12:3279. [PMID: 34078883 PMCID: PMC8172563 DOI: 10.1038/s41467-021-23478-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 05/03/2021] [Indexed: 02/04/2023] Open
Abstract
Targeting the molecular pathways underlying the cardiotoxicity associated with thoracic irradiation and doxorubicin (Dox) could reduce the morbidity and mortality associated with these anticancer treatments. Here, we find that vascular endothelial cells (ECs) with persistent DNA damage induced by irradiation and Dox treatment exhibit a fibrotic phenotype (endothelial-mesenchymal transition, EndMT) correlating with the colocalization of L1CAM and persistent DNA damage foci. We demonstrate that treatment with the anti-L1CAM antibody Ab417 decreases L1CAM overexpression and nuclear translocation and persistent DNA damage foci. We show that in whole-heart-irradiated mice, EC-specific p53 deletion increases vascular fibrosis and the colocalization of L1CAM and DNA damage foci, while Ab417 attenuates these effects. We also demonstrate that Ab417 prevents cardiac dysfunction-related decrease in fractional shortening and prolongs survival after whole-heart irradiation or Dox treatment. We show that cardiomyopathy patient-derived cardiovascular ECs with persistent DNA damage show upregulated L1CAM and EndMT, indicating clinical applicability of Ab417. We conclude that controlling vascular DNA damage by inhibiting nuclear L1CAM translocation might effectively prevent anticancer therapy-associated cardiotoxicity.
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Affiliation(s)
- Jae-Kyung Nam
- grid.415464.60000 0000 9489 1588Division of Radiation Biomedical Research, Korea Institute of Radiological & Medical Sciences, Seoul, Korea ,grid.222754.40000 0001 0840 2678Laboratory of Biochemistry, Division of Life Sciences, Korea University, Seoul, Korea
| | - A-Ram Kim
- grid.415464.60000 0000 9489 1588Division of Radiation Biomedical Research, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
| | - Seo-Hyun Choi
- grid.415464.60000 0000 9489 1588Division of Radiation Biomedical Research, Korea Institute of Radiological & Medical Sciences, Seoul, Korea ,grid.51462.340000 0001 2171 9952Department of Surgery, Memorial Sloan Kettering Cancer Center, NY, USA
| | - Ji-Hee Kim
- grid.415464.60000 0000 9489 1588Division of Radiation Biomedical Research, Korea Institute of Radiological & Medical Sciences, Seoul, Korea ,grid.222754.40000 0001 0840 2678Laboratory of Biochemistry, Division of Life Sciences, Korea University, Seoul, Korea
| | - Kyu Jin Choi
- grid.415464.60000 0000 9489 1588Division of Radiation Biomedical Research, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
| | - Seulki Cho
- grid.412010.60000 0001 0707 9039Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, Korea
| | - Jae Won Lee
- grid.412484.f0000 0001 0302 820XBiomedical Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Hyun-Jai Cho
- grid.412484.f0000 0001 0302 820XBiomedical Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Yoo-Wook Kwon
- grid.412484.f0000 0001 0302 820XCardiovascular Center & Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
| | - Jaeho Cho
- grid.15444.300000 0004 0470 5454Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea
| | - Kwang Seok Kim
- grid.415464.60000 0000 9489 1588Division of Radiation Biomedical Research, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
| | - Joon Kim
- grid.222754.40000 0001 0840 2678Laboratory of Biochemistry, Division of Life Sciences, Korea University, Seoul, Korea
| | - Hae-June Lee
- grid.415464.60000 0000 9489 1588Division of Radiation Biomedical Research, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
| | - Tae Sup Lee
- grid.415464.60000 0000 9489 1588Division of RI Convergence Research, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
| | - Sangwoo Bae
- grid.415464.60000 0000 9489 1588Division of Radiation Biomedical Research, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
| | - Hyo Jeong Hong
- grid.412010.60000 0001 0707 9039Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, Korea ,grid.482586.5Scripps Korea Antibody Institute, Chuncheon, Korea
| | - Yoon-Jin Lee
- grid.415464.60000 0000 9489 1588Division of Radiation Biomedical Research, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
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3
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The Life of a Trailing Spouse. J Neurosci 2021; 41:3-10. [PMID: 33408132 DOI: 10.1523/jneurosci.2874-20.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 11/22/2020] [Accepted: 11/24/2020] [Indexed: 11/21/2022] Open
Abstract
In 1981, I published a paper in the first issue of the Journal of Neuroscience with my postdoctoral mentor, Alan Pearlman. It reported a quantitative analysis of the receptive field properties of neurons in reeler mouse visual cortex and the surprising conclusion that although the neuronal somas were strikingly malpositioned, their receptive fields were unchanged. This suggested that in mouse cortex at least, neuronal circuits have very robust systems in place to ensure the proper formation of connections. This had the unintended consequence of transforming me from an electrophysiologist into a cellular and molecular neuroscientist who studied cell adhesion molecules and the molecular mechanisms they use to regulate axon growth. It took me a surprisingly long time to appreciate that your science is driven by the people around you and by the technologies that are locally available. As a professional puzzler, I like all different kinds of puzzles, but the most fun puzzles involve playing with other puzzlers. This is my story of learning how to find like-minded puzzlers to solve riddles about axon growth and regeneration.
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4
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ERM Proteins at the Crossroad of Leukocyte Polarization, Migration and Intercellular Adhesion. Int J Mol Sci 2020; 21:ijms21041502. [PMID: 32098334 PMCID: PMC7073024 DOI: 10.3390/ijms21041502] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 12/12/2022] Open
Abstract
Ezrin, radixin and moesin proteins (ERMs) are plasma membrane (PM) organizers that link the actin cytoskeleton to the cytoplasmic tail of transmembrane proteins, many of which are adhesion receptors, in order to regulate the formation of F-actin-based structures (e.g., microspikes and microvilli). ERMs also effect transmission of signals from the PM into the cell, an action mainly exerted through the compartmentalized activation of the small Rho GTPases Rho, Rac and Cdc42. Ezrin and moesin are the ERMs more highly expressed in leukocytes, and although they do not always share functions, both are mainly regulated through phosphatidylinositol 4,5-bisphosphate (PIP2) binding to the N-terminal band 4.1 protein-ERM (FERM) domain and phosphorylation of a conserved Thr in the C-terminal ERM association domain (C-ERMAD), exerting their functions through a wide assortment of mechanisms. In this review we will discuss some of these mechanisms, focusing on how they regulate polarization and migration in leukocytes, and formation of actin-based cellular structures like the phagocytic cup-endosome and the immune synapse in macrophages/neutrophils and lymphocytes, respectively, which represent essential aspects of the effector immune response.
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5
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Cengiz T, Türkboyları S, Gençler OS, Anlar Ö. The roles of galectin-3 and galectin-4 in the idiopatic Parkinson disease and its progression. Clin Neurol Neurosurg 2019; 184:105373. [PMID: 31147178 DOI: 10.1016/j.clineuro.2019.105373] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 05/07/2019] [Accepted: 05/21/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVES Idiopathic Parkinson's Disease is a neurodegenerative disease caused by the loss of cells that secrete dopamine in the basal ganglia. Galectins are multipotent, evolutionarily conserved, cell surface glycoconjugated and crosslinked carbohydrate-binding proteins. The roles of these proteins in the diagnosis of the disease have been investigated. PATIENT AND METHODS Patients who were diagnosed with idiopathic Parkinson's disease were classified as early (stage 1-2) and advanced stage (stage 3-5) according to the Hoehn-Yahr classification. In addition, voluntary cases without parkinson disease constituted the control group. Serum samples of consecutive Parkinson patients and age and gender matched healthy controls were used to measure serum galectin-3 and serum galectin-4 levels. The levels were compared between Parkinson's patients and control groups and early and advanced stage Parkinson's groups. RESULTS Thirty age and gender-matched healthy controls and 60 parkinson patients were enrolled in the study. Serum galectin-3 levels were lower in controls compared with patients (892.9 (168.2-2416.3) vs. 2271.8 (375.9-9673.4), respectively, P < 0.01). Serum galectin-3 levels were related to Hoehn-Yahr stages and (r: 0.691, P < 0.001). The early stage group (20 patients) had lower serum galectin-4 levels compared with advanced stages (40 patients) (197.97 ± 46.42 vs. 334.263 ± 37, respectively, P < 0.01). Serum galectin-4 levels were also lower in controls compared with patients 185.1 (116.2-313.3) vs. 282.3 (156.9-984.8), respectively, P < 0.01. ROC analysis showed that serum galectin-3 and galectin-4 were statistically significant in the identification of Parkinson disease and advanced stages. The results were significant for galectin-3 (AUC: 0.89, SE: 0.034, P < 0.001 and CI: 0.823-0.958; P < 0.001) and for galectin-4 (AUC: 0.758, SE: 0.05, P < 0.001). CONCLUSION Serum galectin-3 and galectin-4 may be potential noninvasive markers for the identification of Parkinson disease and advanced stages.
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Affiliation(s)
- Tuğba Cengiz
- Atatürk Training and Research Hospital, Department of Neurology, 06800, Bilkent, Ankara, Turkey.
| | - Saadet Türkboyları
- Dr. A.Y. Ankara Oncology Training and Research Hospital, Department of Neurology, 06520, Bilkent, Ankara, Turkey
| | - Onur Serdar Gençler
- Medical Park Hospital, Department of Neurology, 06370 Batıkent, Ankara, Turkey
| | - Ömer Anlar
- Yıldırım Beyazıt University Faculty of Medicine, Department of Neurology, 06800, Bilkent, Ankara, Turkey
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Kakad PP, Penserga T, Davis BP, Henry B, Boerner J, Riso A, Pielage J, Godenschwege TA. An ankyrin-binding motif regulates nuclear levels of L1-type neuroglian and expression of the oncogene Myc in Drosophila neurons. J Biol Chem 2018; 293:17442-17453. [PMID: 30257867 DOI: 10.1074/jbc.ra118.004240] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/18/2018] [Indexed: 12/26/2022] Open
Abstract
L1 cell adhesion molecule (L1CAM) is well-known for its importance in nervous system development and cancer progression. In addition to its role as a plasma membrane protein in cytoskeletal organization, recent in vitro studies have revealed that both transmembrane and cytosolic fragments of proteolytically cleaved vertebrate L1CAM translocate to the nucleus. In vitro studies indicate that nuclear L1CAM affects genes with functions in DNA post-replication repair, cell cycle control, and cell migration and differentiation, but its in vivo role and how its nuclear levels are regulated is less well-understood. Here, we report that mutations in the conserved ankyrin-binding domain affect nuclear levels of the sole Drosophila homolog neuroglian (Nrg) and that it also has a noncanonical role in regulating transcript levels of the oncogene Myc in the adult nervous system. We further show that altered nuclear levels of Nrg correlate with altered transcript levels of Myc in neurons, similar to what has been reported for human glioblastoma stem cells. However, whereas previous in vitro studies suggest that increased nuclear levels of L1CAM promote tumor cell survival, we found here that elevated levels of nuclear Nrg in neurons are associated with increased sensitivity to oxidative stress and reduced life span of adult animals. We therefore conclude that these findings are of potential relevance to the management of neurodegenerative diseases associated with oxidative stress and cancer.
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Affiliation(s)
| | | | | | | | | | - Anna Riso
- the Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, Florida 33458 and
| | - Jan Pielage
- the Department of Biology, Division of Zoology/Neurobiology, University of Kaiserslautern, Kaiserslautern 67653, Germany
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7
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Ma L, Liu YP, Geng CZ, Xing LX, Zhang XH. Low-dose epirubicin inhibits ezrin-mediated metastatic behavior of breast cancer cells. TUMORI JOURNAL 2018; 97:400-5. [DOI: 10.1177/030089161109700324] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aims and background Overexpression of ezrin contributes to the progression and invasiveness of several human cancers; however, its role in breast cancer metastasis has not been investigated in detail. Methods Ezrin expression in tissue samples from patients with invasive ductal carcinoma of the breast was detected by immunohistochemistry. Ezrin expression in a breast cancer cell line was evaluated using Western blot and RT-PCR. Results Elevated expression of ezrin was associated with lymph node metastasis and poor prognosis in patients with invasive ductal carcinoma. Ezrin expression was related to the invasiveness of breast cancer cells in vitro. Low-dose epirubicin inhibited the migration of breast cancer cells in a concentration-dependent manner without promoting cytotoxicity in vitro and decreased the expression of ezrin in a concentration-dependent manner. Conclusions Low-dose epirubicin may be antimetastatic without promoting cytotoxic effects and could serve as a target for the development of therapeutics for breast carcinoma.
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Affiliation(s)
- Li Ma
- Breast Center, Institute of the Fourth Hospital of Hebei Medical University, Shijiazhuang
| | - Yue-Ping Liu
- Department of Pathology, Institute of the Fourth Hospital of Hebei Medical University, Shijiazhuang
| | - Cui-Zhi Geng
- Breast Center, Institute of the Fourth Hospital of Hebei Medical University, Shijiazhuang
| | - Ling-Xiao Xing
- Department of Pathological Laboratory, Institute of Basic Medical Science, Hebei Medical University, Shijiazhuang, PR China
| | - Xiang-Hong Zhang
- Department of Pathological Laboratory, Institute of Basic Medical Science, Hebei Medical University, Shijiazhuang, PR China
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8
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Freymuth PS, Fitzsimons HL. The ERM protein Moesin is essential for neuronal morphogenesis and long-term memory in Drosophila. Mol Brain 2017; 10:41. [PMID: 28851405 PMCID: PMC5576258 DOI: 10.1186/s13041-017-0322-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 08/23/2017] [Indexed: 11/10/2022] Open
Abstract
Moesin is a cytoskeletal adaptor protein that plays an important role in modification of the actin cytoskeleton. Rearrangement of the actin cytoskeleton drives both neuronal morphogenesis and the structural changes in neurons that are required for long-term memory formation. Moesin has been identified as a candidate memory gene in Drosophila, however, whether it is required for memory formation has not been evaluated. Here, we investigate the role of Moesin in neuronal morphogenesis and in short- and long-term memory formation in the courtship suppression assay, a model of associative memory. We found that both knockdown and overexpression of Moesin led to defects in axon growth and guidance as well as dendritic arborization. Moreover, reduction of Moesin expression or expression of a constitutively active phosphomimetic in the adult Drosophila brain had no effect on short term memory, but prevented long-term memory formation, an effect that was independent of its role in development. These results indicate a critical role for Moesin in both neuronal morphogenesis and long-term memory formation.
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Affiliation(s)
- Patrick S Freymuth
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Helen L Fitzsimons
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
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9
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Cornejo VH, Luarte A, Couve A. Global and local mechanisms sustain axonal proteostasis of transmembrane proteins. Traffic 2017; 18:255-266. [PMID: 28220989 DOI: 10.1111/tra.12472] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 02/02/2017] [Accepted: 02/16/2017] [Indexed: 12/22/2022]
Abstract
The control of neuronal protein homeostasis or proteostasis is tightly regulated both spatially and temporally, assuring accurate and integrated responses to external or intrinsic stimuli. Local or autonomous responses in dendritic and axonal compartments are crucial to sustain function during development, physiology and in response to damage or disease. Axons are responsible for generating and propagating electrical impulses in neurons, and the establishment and maintenance of their molecular composition are subject to extreme constraints exerted by length and size. Proteins that require the secretory pathway, such as receptors, transporters, ion channels or cell adhesion molecules, are fundamental for axonal function, but whether axons regulate their abundance autonomously and how they achieve this is not clear. Evidence supports the role of three complementary mechanisms to maintain proteostasis of these axonal proteins, namely vesicular transport, local translation and trafficking and transfer from supporting cells. Here, we review these mechanisms, their molecular machineries and contribution to neuronal function. We also examine the signaling pathways involved in local translation and their role during development and nerve injury. We discuss the relative contributions of a transport-controlled proteome directed by the soma (global regulation) versus a local-controlled proteome based on local translation or cell transfer (local regulation).
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Affiliation(s)
- Víctor Hugo Cornejo
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
| | - Alejandro Luarte
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
| | - Andrés Couve
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
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10
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Inhibition of N1-Src kinase by a specific SH3 peptide ligand reveals a role for N1-Src in neurite elongation by L1-CAM. Sci Rep 2017; 7:43106. [PMID: 28220894 PMCID: PMC5318895 DOI: 10.1038/srep43106] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 01/19/2017] [Indexed: 11/09/2022] Open
Abstract
In the mammalian brain the ubiquitous tyrosine kinase, C-Src, undergoes splicing to insert short sequences in the SH3 domain to yield N1- and N2-Src. We and others have previously shown that the N-Srcs have altered substrate specificity and kinase activity compared to C-Src. However, the exact functions of the N-Srcs are unknown and it is likely that N-Src signalling events have been misattributed to C-Src because they cannot be distinguished by conventional Src inhibitors that target the kinase domain. By screening a peptide phage display library, we discovered a novel ligand (PDN1) that targets the unique SH3 domain of N1-Src and inhibits N1-Src in cells. In cultured neurons, PDN1 fused to a fluorescent protein inhibited neurite outgrowth, an effect that was mimicked by shRNA targeting the N1-Src microexon. PDN1 also inhibited L1-CAM-dependent neurite elongation in cerebellar granule neurons, a pathway previously shown to be disrupted in Src−/− mice. PDN1 therefore represents a novel tool for distinguishing the functions of N1-Src and C-Src in neurons and is a starting point for the development of a small molecule inhibitor of N1-Src.
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11
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Higuero AM, Díez-Revuelta N, Abad-Rodríguez J. The sugar code in neuronal physiology. Histochem Cell Biol 2016; 147:257-267. [PMID: 27999993 DOI: 10.1007/s00418-016-1519-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2016] [Indexed: 10/20/2022]
Abstract
Carbohydrate-related interactions are necessary for the correct development and function of the nervous system. As we illustrate with several examples, those interactions are controlled by carbohydrate-modifying enzymes and by carbohydrate-binding proteins that regulate a plethora of complex axonal processes. Among others, glycan-related proteins as sialidase Neu3 or galectins-1, -3, and -4 play central roles in the determination of axonal fate, axon growth, guidance and regeneration, as well as in polarized axonal glycoprotein transport. In addition, myelination is also highly dependent on glycans, and the stabilization of myelin architecture requires the interaction of the myelin-associated glycoprotein (siglec-4) with gangliosides in the axonal membrane. The roles of glycans in neuroscience are far from being completely understood, though the cases presented here underscore the importance and potential of carbohydrates to establish with precision key molecular mechanisms of the physiology of the nervous system. New specific applications in diagnosis as well as the definition of new molecular targets to treat neurological diseases related to lectins and/or glycans are envisioned in the future.
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Affiliation(s)
- Alonso M Higuero
- Membrane Biology and Axonal Repair Laboratory, National Hospital for Paraplegics (SESCAM), Finca La Peraleda s/n, 45071, Toledo, Spain
| | - Natalia Díez-Revuelta
- Membrane Biology and Axonal Repair Laboratory, National Hospital for Paraplegics (SESCAM), Finca La Peraleda s/n, 45071, Toledo, Spain
| | - José Abad-Rodríguez
- Membrane Biology and Axonal Repair Laboratory, National Hospital for Paraplegics (SESCAM), Finca La Peraleda s/n, 45071, Toledo, Spain.
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Abstract
Galectin-4, a tandem repeat member of the β-galactoside-binding proteins, possesses two carbohydrate-recognition domains (CRD) in a single peptide chain. This lectin is mostly expressed in epithelial cells of the intestinal tract and secreted to the extracellular. The two domains have 40% similarity in amino acid sequence, but distinctly binding to various ligands. Just because the two domains bind to different ligands simultaneously, galectin-4 can be a crosslinker and crucial regulator in a large number of biological processes. Recent evidence shows that galectin-4 plays an important role in lipid raft stabilization, protein apical trafficking, cell adhesion, wound healing, intestinal inflammation, tumor progression, etc. This article reviews the physiological and pathological features of galectin-4 and its important role in such processes.
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13
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Leshchyns'ka I, Sytnyk V. Reciprocal Interactions between Cell Adhesion Molecules of the Immunoglobulin Superfamily and the Cytoskeleton in Neurons. Front Cell Dev Biol 2016; 4:9. [PMID: 26909348 PMCID: PMC4754453 DOI: 10.3389/fcell.2016.00009] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 02/01/2016] [Indexed: 12/04/2022] Open
Abstract
Cell adhesion molecules of the immunoglobulin superfamily (IgSF) including the neural cell adhesion molecule (NCAM) and members of the L1 family of neuronal cell adhesion molecules play important functions in the developing nervous system by regulating formation, growth and branching of neurites, and establishment of the synaptic contacts between neurons. In the mature brain, members of IgSF regulate synapse composition, function, and plasticity required for learning and memory. The intracellular domains of IgSF cell adhesion molecules interact with the components of the cytoskeleton including the submembrane actin-spectrin meshwork, actin microfilaments, and microtubules. In this review, we summarize current data indicating that interactions between IgSF cell adhesion molecules and the cytoskeleton are reciprocal, and that while IgSF cell adhesion molecules regulate the assembly of the cytoskeleton, the cytoskeleton plays an important role in regulation of the functions of IgSF cell adhesion molecules. Reciprocal interactions between NCAM and L1 family members and the cytoskeleton and their role in neuronal differentiation and synapse formation are discussed in detail.
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Affiliation(s)
- Iryna Leshchyns'ka
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales Sydney, NSW, Australia
| | - Vladimir Sytnyk
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales Sydney, NSW, Australia
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14
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Antoine-Bertrand J, Fu M, Lamarche-Vane N. Direct measurement of oscillatory RhoA activity in embryonic cortical neurons stimulated with the axon guidance cue netrin-1 using fluorescence resonance energy transfer. Biol Cell 2016; 108:115-26. [PMID: 26787017 DOI: 10.1111/boc.201500077] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 01/15/2016] [Indexed: 12/27/2022]
Abstract
BACKGROUND INFORMATION Rho GTPases play an essential role during the development of the nervous system. They induce cytoskeletal rearrangements that are critical for the regulation of axon outgrowth and guidance. It is generally accepted that Rac1 and Cdc42 are positive regulators of axon outgrowth and guidance, whereas RhoA is a negative regulator. However, spatiotemporal control of their activity can modify the function of Rho GTPases during axonal morphogenesis. Signalling downstream of the axon guidance cue netrin-1 and its receptor deleted in colorectal cancer (DCC) triggers the activation of Rac1 and the inhibition of RhoA to promote axon outgrowth. However, our previous work also suggests that netrin-1/DCC signalling can activate RhoA in a time- and region-specific manner. RESULTS Here, we visualised RhoA activation in response to netrin-1 in live embryonic cortical neurons using fluorescence resonance energy transfer. RhoA activity oscillated in unstimulated neurons and netrin-1 increased the amplitude of the oscillations in growth cones after 5 min of stimulation. Within this period of time, netrin-1 transiently increased RhoA activity and modulated the pattern of RhoA oscillations. We found that the timing of netrin-1-induced RhoA activation was different in whole neurons, cell bodies and growth cones. CONCLUSIONS We conclude that netrin-1 modulates the spatiotemporal activation of RhoA in embryonic cortical neurons. SIGNIFICANCE This study demonstrates for the first time the short-term localised activation of RhoA in neuronal growth cones by the axon guidance cue netrin-1.
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Affiliation(s)
- Judith Antoine-Bertrand
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada.,Cancer Research Program, Research Institute of the McGill University Health Centre (RI-MUHC), Montreal, Quebec, Canada
| | - Min Fu
- Cancer Research Program, Research Institute of the McGill University Health Centre (RI-MUHC), Montreal, Quebec, Canada
| | - Nathalie Lamarche-Vane
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada.,Cancer Research Program, Research Institute of the McGill University Health Centre (RI-MUHC), Montreal, Quebec, Canada
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15
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Cell Adhesion Molecules and Ubiquitination-Functions and Significance. BIOLOGY 2015; 5:biology5010001. [PMID: 26703751 PMCID: PMC4810158 DOI: 10.3390/biology5010001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/02/2015] [Accepted: 12/15/2015] [Indexed: 12/11/2022]
Abstract
Cell adhesion molecules of the immunoglobulin (Ig) superfamily represent the biggest group of cell adhesion molecules. They have been analyzed since approximately 40 years ago and most of them have been shown to play a role in tumor progression and in the nervous system. All members of the Ig superfamily are intensively posttranslationally modified. However, many aspects of their cellular functions are not yet known. Since a few years ago it is known that some of the Ig superfamily members are modified by ubiquitin. Ubiquitination has classically been described as a proteasomal degradation signal but during the last years it became obvious that it can regulate many other processes including internalization of cell surface molecules and lysosomal sorting. The purpose of this review is to summarize the current knowledge about the ubiquitination of cell adhesion molecules of the Ig superfamily and to discuss its potential physiological roles in tumorigenesis and in the nervous system.
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Flores-Benitez D, Knust E. Crumbs is an essential regulator of cytoskeletal dynamics and cell-cell adhesion during dorsal closure in Drosophila. eLife 2015; 4. [PMID: 26544546 PMCID: PMC4718732 DOI: 10.7554/elife.07398] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 11/06/2015] [Indexed: 12/12/2022] Open
Abstract
The evolutionarily conserved Crumbs protein is required for epithelial polarity and morphogenesis. Here we identify a novel role of Crumbs as a negative regulator of actomyosin dynamics during dorsal closure in the Drosophila embryo. Embryos carrying a mutation in the FERM (protein 4.1/ezrin/radixin/moesin) domain-binding motif of Crumbs die due to an overactive actomyosin network associated with disrupted adherens junctions. This phenotype is restricted to the amnioserosa and does not affect other embryonic epithelia. This function of Crumbs requires DMoesin, the Rho1-GTPase, class-I p21-activated kinases and the Arp2/3 complex. Data presented here point to a critical role of Crumbs in regulating actomyosin dynamics, cell junctions and morphogenesis. DOI:http://dx.doi.org/10.7554/eLife.07398.001 A layer of epithelial cells covers the body surface of animals. Epithelial cells have a property known as polarity; this means that they have two different poles, one of which is in contact with the environment. Midway through embryonic development, the Drosophila embryo is covered by two kinds of epithelial sheets; the epidermis on the front, the belly and the sides of the embryo, and the amnioserosa on the back. In the second half of embryonic development, the amnioserosa is brought into the embryo in a process called dorsal closure, while the epidermis expands around the back of the embryo to encompass it. One of the major activities driving dorsal closure is the contraction of amnioserosa cells. This contraction depends on the highly dynamic activity of the protein network that helps give cells their shape, known as the actomyosin cytoskeleton. One major question in the field is how changes in the actomyosin cytoskeleton are controlled as tissues take shape (a process known as “morphogenesis”) and how the integrity of epithelial tissues is maintained during these processes. A key regulator of epidermal and amnioserosa polarity is an evolutionarily conserved protein called Crumbs. The epithelial tissues of mutant embryos that do not produce Crumbs lose polarity and integrity, and the embryos fail to develop properly. Flores-Benitez and Knust have now studied the role of Crumbs in the morphogenesis of the amnioserosa during dorsal closure. This revealed that fly embryos that produce a mutant Crumbs protein that cannot interact with a protein called Moesin (which links the cell membrane and the actomyosin cytoskeleton) are unable to complete dorsal closure. Detailed analyses showed that this failure of dorsal closure is due to the over-activity of the actomyosin cytoskeleton in the amnioserosa. This results in increased and uncoordinated contractions of the cells, and is accompanied by defects in cell-cell adhesion that ultimately cause the amnioserosa to lose integrity. Flores-Benitez and Knust’s genetic analyses further showed that several different signalling systems participate in this process. Flores-Benitez and Knust’s results reveal an unexpected role of Crumbs in coordinating polarity, actomyosin activity and cell-cell adhesion. Further work is now needed to understand the molecular mechanisms and interactions that enable Crumbs to coordinate these processes; in particular, to unravel how Crumbs influences the periodic contractions that drive changes in cell shape. It will also be important to investigate whether Crumbs is involved in similar mechanisms that operate in other developmental events in which actomyosin oscillations have been linked to tissue morphogenesis. DOI:http://dx.doi.org/10.7554/eLife.07398.002
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Affiliation(s)
| | - Elisabeth Knust
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany
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17
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Siegenthaler D, Enneking EM, Moreno E, Pielage J. L1CAM/Neuroglian controls the axon-axon interactions establishing layered and lobular mushroom body architecture. ACTA ACUST UNITED AC 2015; 208:1003-18. [PMID: 25825519 PMCID: PMC4384726 DOI: 10.1083/jcb.201407131] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The establishment of neuronal circuits depends on the guidance of axons both along and in between axonal populations of different identity; however, the molecular principles controlling axon-axon interactions in vivo remain largely elusive. We demonstrate that the Drosophila melanogaster L1CAM homologue Neuroglian mediates adhesion between functionally distinct mushroom body axon populations to enforce and control appropriate projections into distinct axonal layers and lobes essential for olfactory learning and memory. We addressed the regulatory mechanisms controlling homophilic Neuroglian-mediated cell adhesion by analyzing targeted mutations of extra- and intracellular Neuroglian domains in combination with cell type-specific rescue assays in vivo. We demonstrate independent and cooperative domain requirements: intercalating growth depends on homophilic adhesion mediated by extracellular Ig domains. For functional cluster formation, intracellular Ankyrin2 association is sufficient on one side of the trans-axonal complex whereas Moesin association is likely required simultaneously in both interacting axonal populations. Together, our results provide novel mechanistic insights into cell adhesion molecule-mediated axon-axon interactions that enable precise assembly of complex neuronal circuits.
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Affiliation(s)
- Dominique Siegenthaler
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland University of Basel, 4003 Basel, Switzerland
| | - Eva-Maria Enneking
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland University of Basel, 4003 Basel, Switzerland
| | - Eliza Moreno
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Jan Pielage
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
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18
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Abad-Rodríguez J, Díez-Revuelta N. Axon glycoprotein routing in nerve polarity, function, and repair. Trends Biochem Sci 2015; 40:385-96. [PMID: 25936977 DOI: 10.1016/j.tibs.2015.03.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/13/2015] [Accepted: 03/31/2015] [Indexed: 02/04/2023]
Abstract
Nervous system function relies on the capacity of neurons to organize specialized domains for impulse reception or transmission. Such a polarized architecture relies on highly discriminatory and efficient mechanisms for the transport and targeting of required molecules to their functional positions. Glycans play a central role in polarized traffic based on their extraordinary capacity to encrypt bio-information. Glycan-based interactions exquisitely regulate cargo selection, trafficking, and targeting to the axon membrane. This generates segregated functional domains, where basal nerve processes such as axon growth, synaptic activity, or myelination take place. Deciphering the details of the glycan structures and carbohydrate-binding molecules that underlie these mechanisms improves our knowledge of nerve physiology and defines novel specific approaches for neurological treatments.
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Affiliation(s)
- José Abad-Rodríguez
- Membrane Biology and Axonal Repair Laboratory, Hospital Nacional de Parapléjicos (SESCAM), Finca La Peraleda s/n, 45071 Toledo, Spain.
| | - Natalia Díez-Revuelta
- Membrane Biology and Axonal Repair Laboratory, Hospital Nacional de Parapléjicos (SESCAM), Finca La Peraleda s/n, 45071 Toledo, Spain
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Nagaraj K, Mualla R, Hortsch M. The L1 Family of Cell Adhesion Molecules: A Sickening Number of Mutations and Protein Functions. ADVANCES IN NEUROBIOLOGY 2014; 8:195-229. [DOI: 10.1007/978-1-4614-8090-7_9] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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20
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Differential effects of human L1CAM mutations on complementing guidance and synaptic defects in Drosophila melanogaster. PLoS One 2013; 8:e76974. [PMID: 24155914 PMCID: PMC3796554 DOI: 10.1371/journal.pone.0076974] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 09/05/2013] [Indexed: 01/17/2023] Open
Abstract
A large number of different pathological L1CAM mutations have been identified that result in a broad spectrum of neurological and non-neurological phenotypes. While many of these mutations have been characterized for their effects on homophilic and heterophilic interactions, as well as expression levels in vitro, there are only few studies on their biological consequences in vivo. The single L1-type CAM gene in Drosophila, neuroglian (nrg), has distinct functions during axon guidance and synapse formation and the phenotypes of nrg mutants can be rescued by the expression of human L1CAM. We previously showed that the highly conserved intracellular FIGQY Ankyrin-binding motif is required for L1CAM-mediated synapse formation, but not for neurite outgrowth or axon guidance of the Drosophila giant fiber (GF) neuron. Here, we use the GF as a model neuron to characterize the pathogenic L120V, Y1070C, C264Y, H210Q, E309K and R184Q extracellular L1CAM missense mutations and a L1CAM protein with a disrupted ezrin-moesin-radixin (ERM) binding site to investigate the signaling requirements for neuronal development. We report that different L1CAM mutations have distinct effects on axon guidance and synapse formation. Furthermore, L1CAM homophilic binding and signaling via the ERM motif is essential for axon guidance in Drosophila. In addition, the human pathological H210Q, R184Q and Y1070C, but not the E309K and L120V L1CAM mutations affect outside-in signaling via the FIGQY Ankyrin binding domain which is required for synapse formation. Thus, the pathological phenotypes observed in humans are likely to be caused by the disruption of signaling required for both, guidance and synaptogenesis.
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21
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Aikawa Y. Ubiquitination within the membrane-proximal ezrin-radixin-moesin (ERM)-binding region of the L1 cell adhesion molecule. Commun Integr Biol 2013; 6:e24750. [PMID: 23986810 PMCID: PMC3737756 DOI: 10.4161/cib.24750] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 04/19/2013] [Accepted: 04/19/2013] [Indexed: 12/14/2022] Open
Abstract
The dynamic turnover of the L1 cell adhesion molecule to and from the plasma membrane that is mediated through exo-and endocytic trafficking is central to axon outgrowth. Although the ubiquitination of L1 in response to incubation with an L1 antibody that mimics L1-L1 homophilic binding has been previously shown, the endocytic trafficking pathway of the ubiquitinated L1 destined for degradation is yet unclear. I have recently shown that the ubiquitinated L1 is endocytosed by Rabex-5, which is an ubiquitin-binding protein and guanine nucleotide exchange factor for Rab5, into early endosomes from the plasma membrane. Here, I speculate on the putative ubiquitination site within the membrane-proximal ezrin-binding motif in the cytoplasmic domain of L1 and discuss the regulatory role of this motif in the competition between ubiquitination and the binding of ezrin prior to L1 internalization.
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Affiliation(s)
- Yoshikatsu Aikawa
- Laboratory of Neural Membrane Biology; Graduate School of Brain Science; Doshisha University; Kyoto, Japan
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22
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Sepulveda B, Mesias R, Li X, Yue Z, Benson DL. Short- and long-term effects of LRRK2 on axon and dendrite growth. PLoS One 2013; 8:e61986. [PMID: 23646112 PMCID: PMC3640004 DOI: 10.1371/journal.pone.0061986] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 03/15/2013] [Indexed: 11/18/2022] Open
Abstract
Mutations in leucine-rich repeat kinase 2 (LRRK2) underlie an autosomal-dominant form of Parkinson's disease (PD) that is clinically indistinguishable from idiopathic PD. The function of LRRK2 is not well understood, but it has become widely accepted that LRRK2 levels or its kinase activity, which is increased by the most commonly observed mutation (G2019S), regulate neurite growth. However, growth has not been measured; it is not known whether mean differences in length correspond to altered rates of growth or retraction, whether axons or dendrites are impacted differentially or whether effects observed are transient or sustained. To address these questions, we compared several developmental milestones in neurons cultured from mice expressing bacterial artificial chromosome transgenes encoding mouse wildtype-LRRK2 or mutant LRRK2-G2019S, Lrrk2 knockout mice and non-transgenic mice. Over the course of three weeks of development on laminin, the data show a sustained, negative effect of LRRK2-G2019S on dendritic growth and arborization, but counter to expectation, dendrites from Lrrk2 knockout mice do not elaborate more rapidly. In contrast, young neurons cultured on a slower growth substrate, poly-L-lysine, show significantly reduced axonal and dendritic motility in Lrrk2 transgenic neurons and significantly increased motility in Lrrk2 knockout neurons with no significant changes in length. Our findings support that LRRK2 can regulate patterns of axonal and dendritic growth, but they also show that effects vary depending on growth substrate and stage of development. Such predictable changes in motility can be exploited in LRRK2 bioassays and guide exploration of LRRK2 function in vivo.
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Affiliation(s)
- Bryan Sepulveda
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
- Graduate School of Biological Sciences, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Roxana Mesias
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Xianting Li
- Department of Neurology, Friedman Brain Institute, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Zhenyu Yue
- Department of Neurology, Friedman Brain Institute, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Deanna L. Benson
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
- * E-mail:
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23
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Velasco S, Díez-Revuelta N, Hernández-Iglesias T, Kaltner H, André S, Gabius HJ, Abad-Rodríguez J. Neuronal Galectin-4 is required for axon growth and for the organization of axonal membrane L1 delivery and clustering. J Neurochem 2013; 125:49-62. [DOI: 10.1111/jnc.12148] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 01/05/2013] [Indexed: 12/19/2022]
Affiliation(s)
- Silvia Velasco
- Membrane Biology and Axonal Repair Laboratory; Hospital Nacional de Parapléjicos (SESCAM), Finca La Peraleda s/n; Toledo Spain
| | - Natalia Díez-Revuelta
- Membrane Biology and Axonal Repair Laboratory; Hospital Nacional de Parapléjicos (SESCAM), Finca La Peraleda s/n; Toledo Spain
| | | | - Herbert Kaltner
- Institut für Physiologische Chemie, Tierärztliche Fakultät, Ludwig-Maximilians-Universität; München Germany
| | - Sabine André
- Institut für Physiologische Chemie, Tierärztliche Fakultät, Ludwig-Maximilians-Universität; München Germany
| | - Hans-Joachim Gabius
- Institut für Physiologische Chemie, Tierärztliche Fakultät, Ludwig-Maximilians-Universität; München Germany
| | - José Abad-Rodríguez
- Membrane Biology and Axonal Repair Laboratory; Hospital Nacional de Parapléjicos (SESCAM), Finca La Peraleda s/n; Toledo Spain
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24
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Kobayashi Y, Harada A, Furuta B, Asou H, Kato U, Umeda M. The role of NADRIN, a Rho GTPase-activating protein, in the morphological differentiation of astrocytes. J Biochem 2013; 153:389-98. [DOI: 10.1093/jb/mvt005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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25
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Kashimoto R, Yamanaka H, Kobayashi K, Okubo M, Yagi H, Mimura O, Noguchi K. Phosphorylation of ezrin/radixin/moesin (ERM) protein in spinal microglia following peripheral nerve injury and lysophosphatidic acid administration. Glia 2012; 61:338-48. [PMID: 23065679 DOI: 10.1002/glia.22436] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 09/18/2012] [Indexed: 11/09/2022]
Abstract
Peripheral nerve injury activates spinal glial cells, which may contribute to the development of pain behavioral hypersensitivity. There is growing evidence that activated microglia show dynamic changes in cell morphology; however, the molecular mechanisms that underlie the modification of the membrane and cytoskeleton of microglia are not known. Here, we investigated the phosphorylation of ezrin, radixin, and moesin (ERM) proteins in the spinal cord after peripheral nerve injury. ERM is known to function as membrane-cytoskeletal linkers and be localized at filopodia- and microvilli-like structures. ERM proteins must be phosphorylated at a specific C-terminal threonine residue to be in the active state. The nature of ERM proteins in the spinal cord of animals in a neuropathic pain model has not been investigated and characterized. In the present study, we observed an increase in the phosphorylated ERM in the spinal microglia following spared nerve injury. The intrathecal administration of lysophosphatidic acid induced the phosphorylation of ERM proteins in microglia along with the development of mechanical pain hypersensitivity. Intrathecal administration of ERM antisense locked nucleic acid suppressed nerve injury-induced tactile allodynia and decreased the phosphorylation of ERM, but not the Iba1 staining pattern, in spinal glial cells. These findings suggest that lysophosphatidic acid induced the phosphorylation of ERM proteins in spinal microglia and may be involved in the emergence of neuropathic pain. These findings may underlie the pathological mechanisms of nerve injury-induced neuropathic pain.
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Affiliation(s)
- Ryosuke Kashimoto
- Department of Ophthalmology, Hyogo College of Medicine, Nishinomiya, Japan
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26
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Littner Y, Tang N, He M, Bearer CF. L1 cell adhesion molecule signaling is inhibited by ethanol in vivo. Alcohol Clin Exp Res 2012; 37:383-9. [PMID: 23050935 DOI: 10.1111/j.1530-0277.2012.01944.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 07/09/2012] [Indexed: 01/12/2023]
Abstract
BACKGROUND Fetal alcohol spectrum disorder is an immense public health problem. In vitro studies support the hypothesis that L1 cell adhesion molecule (L1) is a target for ethanol (EtOH) developmental neurotoxicity. L1 is critical for the development of the central nervous system. It functions through signal transduction leading to phosphorylation and dephosphorylation of tyrosines on its cytoplasmic domain. The function of L1 is also dependent on trafficking through lipid rafts (LRs). Our hypothesis is that L1 is a target for EtOH neurotoxicity in vivo. Our objective is to demonstrate changes in L1 phosphorylation/dephosphorylation and LR association in vivo. METHODS Rat pups on postnatal day 6 are administered 4.5, 5.25, and 6 g/kg of EtOH divided into 2 doses 2 hours apart, then killed. Cerebella are rapidly frozen for assay. Blood is analyzed for blood EtOH concentration. L1 tyrosine phosphorylation is determined by immunoprecipitation and dephosphorylation of tyrosine 1176 determined by immunoblot. LRs are isolated by sucrose density gradient, and the distribution of L1 in LRs is determined. RESULTS EtOH at all doses reduced the relative amount of Y1176 dephosphorylation as well as the relative amount of L1 phosphorylated on other tyrosines. The proportion of L1 present in LRs is significantly increased in pups who received 6 g/kg EtOH compared to intubated controls. CONCLUSIONS L1 is a target for EtOH developmental neurotoxicity in vivo.
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Affiliation(s)
- Yoav Littner
- Department of Neuroscience, Lerner Research Institute, Children's Hospital, The Cleveland Clinic, Cleveland, Ohio, USA
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27
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Kiefel H, Bondong S, Pfeifer M, Schirmer U, Erbe-Hoffmann N, Schäfer H, Sebens S, Altevogt P. EMT-associated up-regulation of L1CAM provides insights into L1CAM-mediated integrin signalling and NF-κB activation. Carcinogenesis 2012; 33:1919-29. [PMID: 22764136 DOI: 10.1093/carcin/bgs220] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Expression of L1 cell adhesion molecule (L1CAM) is associated with poor prognosis in a variety of human carcinomas including breast, ovarian and pancreatic ductal adenocarcinoma (PDAC). Recently we reported that L1CAM induces sustained nuclear factor kappa B (NF-κB) activation by augmenting the autocrine production of interleukin 1 beta (IL-1β), a process dependent on interaction of L1CAM with integrins. In the present study, we demonstrate that transforming growth factor β1 (TGF-β1) treatment of breast carcinoma (MDA-MB231) and PDAC (BxPc3) cell lines induces an EMT (epithelial to mesenchymal transition)-like phenotype and leads to the expression of L1CAM. In MDA-MB231 cells, up-regulation of L1CAM augmented expression of IL-1β and NF-κB activation, which was reversed by depletion of L1CAM, L1CAM-binding membrane cytoskeleton linker protein ezrin, β1-integrin or focal adhesion kinase (FAK). Over-expression of L1CAM not only induced NF-κB activation but also mediated the phosphorylation of FAK and Src. Phosphorylation was not induced in cells expressing a mutant form of L1CAM (L1-RGE) devoid of the integrin-binding site. FAK- and Src-phosphorylation were inhibited by knock-down of various components of the integrin signalling pathway such as β1- and α5-integrins, integrin-linked kinase (ILK), FAK and the phosphoinositide 3-kinase (PI3K) subunit p110β. In summary, these results reveal that during EMT, L1CAM promotes IL-1β expression through a process dependent on integrin signalling and supports a motile and invasive tumour cell phenotype. We also identify important novel downstream effector molecules of the L1CAM-integrin signalling crosstalk that help to understand the molecular mechanisms underlying L1CAM-promoted tumour progression.
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Affiliation(s)
- Helena Kiefel
- German Cancer Research CenterIm Neuenheimer Feld 280, Heidelberg, Germany
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Kiefel H, Bondong S, Hazin J, Ridinger J, Schirmer U, Riedle S, Altevogt P. L1CAM: a major driver for tumor cell invasion and motility. Cell Adh Migr 2012; 6:374-84. [PMID: 22796939 DOI: 10.4161/cam.20832] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The L1 cell adhesion molecule (L1CAM) plays a major role in the development of the nervous system and in the malignancy of human tumors. In terms of biological function, L1CAM comes along in two different flavors: (1) a static function as a cell adhesion molecule that acts as a glue between cells; (2) a motility promoting function that drives cell migration during neural development and supports metastasis of human cancers. Important factors that contribute to the switch in the functional mode of L1CAM are: (1) the cleavage from the cell surface by membrane proximal proteolysis and (2) the ability to change binding partners and engage in L1CAM-integrin binding. Recent studies have shown that the cleavage of L1CAM by metalloproteinases and the binding of L1CAM to integrins via its RGD-motif in the sixth Ig-domain activate signaling pathways distinct from the ones elicited by homophilic binding. Here we highlight important features of L1CAM proteolysis and the signaling of L1CAM via integrin engagement. The novel insights into L1CAM downstream signaling and its regulation during tumor progression and epithelial-mesenchymal transition (EMT) will lead to a better understanding of the dualistic role of L1CAM as a cell adhesion and/or motility promoting cell surface molecule.
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Affiliation(s)
- Helena Kiefel
- Translational Immunology, German Cancer Research Center, Heidelberg, Germany
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Dai J, Dalal JS, Thakar S, Henkemeyer M, Lemmon VP, Harunaga JS, Schlatter MC, Buhusi M, Maness PF. EphB regulates L1 phosphorylation during retinocollicular mapping. Mol Cell Neurosci 2012; 50:201-10. [PMID: 22579729 DOI: 10.1016/j.mcn.2012.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 04/10/2012] [Accepted: 05/02/2012] [Indexed: 01/24/2023] Open
Abstract
Interaction of the cell adhesion molecule L1 with the cytoskeletal adaptor ankyrin is essential for topographic mapping of retinal ganglion cell (RGC) axons to synaptic targets in the superior colliculus (SC). Mice mutated in the L1 ankyrin-binding motif (FIGQY(1229)H) display abnormal mapping of RGC axons along the mediolateral axis of the SC, resembling mouse mutant phenotypes in EphB receptor tyrosine kinases. To investigate whether L1 functionally interacts with EphBs, we investigated the role of EphB kinases in phosphorylating L1 using a phospho-specific antibody to the tyrosine phosphorylated FIGQY(1229) motif. EphB2, but not an EphB2 kinase dead mutant, induced tyrosine phosphorylation of L1 at FIGQY(1229) and perturbed ankyrin recruitment to the membrane in L1-transfected HEK293 cells. Src family kinases mediated L1 phosphorylation at FIGQY(1229) by EphB2. Other EphB receptors that regulate medial-lateral retinocollicular mapping, EphB1 and EphB3, also mediated phosphorylation of L1 at FIGQY(1229). Tyrosine(1176) in the cytoplasmic domain of L1, which regulates AP2/clathrin-mediated endocytosis and axonal trafficking, was not phosphorylated by EphB2. Accordingly mutation of Tyr(1176) to Ala in L1-Y(1176)A knock-in mice resulted in normal retinocollicular mapping of ventral RGC axons. Immunostaining of the mouse SC during retinotopic mapping showed that L1 colocalized with phospho-FIGQY in RGC axons in retinorecipient layers. Immunoblotting of SC lysates confirmed that L1 was phosphorylated at FIGQY(1229) in wild type but not L1-FIGQY(1229)H (L1Y(1229)H) mutant SC, and that L1 phosphorylation was decreased in the EphB2/B3 mutant SC. Inhibition of ankyrin binding in L1Y(1229)H mutant RGCs resulted in increased neurite outgrowth compared to WT RGCs in retinal explant cultures, suggesting that L1-ankyrin binding serves to constrain RGC axon growth. These findings are consistent with a model in which EphB kinases phosphorylate L1 at FIGQY(1229) in retinal axons to modulate L1-ankyrin binding important for mediolateral retinocollicular topography.
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Affiliation(s)
- Jinxia Dai
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
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30
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Role of L1CAM for axon sprouting and branching. Cell Tissue Res 2012; 349:39-48. [DOI: 10.1007/s00441-012-1345-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 01/25/2012] [Indexed: 01/02/2023]
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Activation of ezrin/radixin/moesin mediates attractive growth cone guidance through regulation of growth cone actin and adhesion receptors. J Neurosci 2012; 32:282-96. [PMID: 22219290 DOI: 10.1523/jneurosci.4794-11.2012] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The development of a functioning neural network relies on responses of axonal growth cones to molecular guidance cues that are encountered en route to their target tissue. Nerve growth factor (NGF) and neurotrophin-3 serve as attractive cues for chick embryo sensory growth cones in vitro and in vivo, but little is known about the actin-binding proteins necessary to mediate this response. The evolutionarily conserved ezrin/radixin/moesin (ERM) family of proteins can tether actin filaments to the cell membrane when phosphorylated at a conserved threonine residue. Here we show that acute neurotrophin stimulation rapidly increases active phospho-ERM levels in chick sensory neuron growth cone filopodia, coincident with an increase in filopodial L1 and β-integrin. Disrupting ERM function with a dominant-negative construct (DN-ERM) results in smaller and less motile growth cones with disorganized actin filaments. Previously, we found that NGF treatment increases actin-depolymerizing factor (ADF)/cofilin activity and growth cone F-actin (Marsick et al., 2010). Here, we show this F-actin increase, as well as attractive turning to NGF, is blocked when ERM function is disrupted despite normal activation of ADF/cofilin. We further show that DN-ERM expression disrupts leading edge localization of active ADF/cofilin and free F-actin barbed ends. Moreover, filopodial phospho-ERM levels are increased by incorporation of active ADF/cofilin and reduced by knockdown of L1CAM.Together, these data suggest that ERM proteins organize actin filaments in sensory neuron growth cones and are crucial for neurotrophin-induced remodeling of F-actin and redistribution of adhesion receptors.
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Antoine-Bertrand J, Ghogha A, Luangrath V, Bedford FK, Lamarche-Vane N. The activation of ezrin-radixin-moesin proteins is regulated by netrin-1 through Src kinase and RhoA/Rho kinase activities and mediates netrin-1-induced axon outgrowth. Mol Biol Cell 2011; 22:3734-46. [PMID: 21849478 PMCID: PMC3183026 DOI: 10.1091/mbc.e10-11-0917] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The receptor Deleted in Colorectal Cancer (DCC) mediates the attractive response of axons to the guidance cue netrin-1 during development. On netrin-1 stimulation, DCC is phosphorylated and induces the assembly of signaling complexes within the growth cone, leading to activation of cytoskeleton regulators, namely the GTPases Rac1 and Cdc42. The molecular mechanisms that link netrin-1/DCC to the actin machinery remain unclear. In this study we seek to demonstrate that the actin-binding proteins ezrin-radixin-moesin (ERM) are effectors of netrin-1/DCC signaling in embryonic cortical neurons. We show that ezrin associates with DCC in a netrin-1-dependent manner. We demonstrate that netrin-1/DCC induces ERM phosphorylation and activation and that the phosphorylation of DCC is required in that context. Moreover, Src kinases and RhoA/Rho kinase activities mediate netrin-1-induced ERM phosphorylation in neurons. We also observed that phosphorylated ERM proteins accumulate in growth cone filopodia, where they colocalize with DCC upon netrin-1 stimulation. Finally, we show that loss of ezrin expression in cortical neurons significantly decreases axon outgrowth induced by netrin-1. Together, our findings demonstrate that netrin-1 induces the formation of an activated ERM/DCC complex in growth cone filopodia, which is required for netrin-1-dependent cortical axon outgrowth.
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Gibson NJ. Cell adhesion molecules in context: CAM function depends on the neighborhood. Cell Adh Migr 2011; 5:48-51. [PMID: 20948304 PMCID: PMC3038097 DOI: 10.4161/cam.5.1.13639] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 09/16/2010] [Indexed: 01/03/2023] Open
Abstract
Cell adhesion molecules (CAMs) are now known to mediate much more than adhesion between cells and between cells and the extracellular matrix. Work by many researchers has illuminated their roles in modulating activation of molecules such as receptor tyrosine kinases, with subsequent effects on cell survival, migration, and process extension. CAMs also are known to serve as substrates for proteases which can create diffusible fragments capable of signaling independently from the CAM. The diversity of interactions is further modulated by membrane rafts, which can co-localize or separate potential signaling partners to affect the likelihood of a given signaling pathway being activated. Given the ever-growing number of known CAMs and the fact that their heterophilic binding in cis or in trans can affect their interactions with other molecules, including membrane-bound receptors, one would predict a wide range of effects attributable to a particular CAM in a particular cell at a particular stage of development. The function(s) of a given CAM must therefore be considered in the context of the history of the cell expressing it and the repertoire of molecules expressed both by that cell and its neighbors.
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Affiliation(s)
- Nicholas J Gibson
- Department of Neuroscience, University of Arizona, Tucson, Arizona, USA.
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Linking L1CAM-mediated signaling to NF-κB activation. Trends Mol Med 2010; 17:178-87. [PMID: 21195665 DOI: 10.1016/j.molmed.2010.11.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 11/19/2010] [Accepted: 11/19/2010] [Indexed: 01/13/2023]
Abstract
The cell adhesion molecule L1 (L1CAM) was originally identified as a neural adhesion molecule essential for neurite outgrowth and axon guidance. Many studies have now shown that L1CAM is overexpressed in human carcinomas and associated with poor prognosis. So far, L1CAM-mediated cellular signaling has been largely attributed to an association with growth factor receptors, referred to as L1CAM-'assisted' signaling. New data demonstrate that L1CAM can signal via two additional mechanisms: 'forward' signaling via regulated intramembrane proteolysis and 'reverse' signaling via the activation of the transcription factor nuclear factor (NF)-κB. Taken together, these findings lead to a new understanding of L1CAM downstream signaling that is fundamental for the development of anti-L1CAM antibody-mediated therapeutics in human tumor cells.
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Flotillin-mediated endocytic events dictate cell type-specific responses to semaphorin 3A. J Neurosci 2010; 30:15317-29. [PMID: 21068336 DOI: 10.1523/jneurosci.1821-10.2010] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cortical efferents growing in the same environment diverge early in development. The expression of particular transcription factors dictates the trajectories taken, presumably by regulating responsiveness to guidance cues via cellular mechanisms that are not yet known. Here, we show that cortical neurons that are dissociated and grown in culture maintain their cell type-specific identities defined by the expression of transcription factors. Using this model system, we sought to identify and characterize mechanisms that are recruited to produce cell type-specific responses to Semaphorin 3A (Sema3A), a guidance cue that would be presented similarly to cortical axons in vivo. Axons from presumptive corticofugal neurons lacking the transcription factor Satb2 and expressing Ctip2 or Tbr1 respond far more robustly to Sema3A than those from presumptive callosal neurons expressing Satb2. Both populations of axons express similar levels of Sema3A receptors (neuropilin-1, cell adhesion molecule L1, and plexinA4), but significantly, axons from neurons lacking Satb2 internalize more Sema3A, and they do so via a raft-mediated endocytic pathway. We used an in silico approach to identify the endocytosis effector flotillin-1 as a Sema3A signaling candidate. We tested the contributions of flotillin-1 to Sema3A endocytosis and signaling, and show that raft-mediated Sema3A endocytosis is defined by and depends on the recruitment of flotillin-1, which mediates LIM domain kinase activation and regulates axon responsiveness to Sema3A in presumptive corticofugal axons.
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Giagtzoglou N, Ly CV, Bellen HJ. Cell adhesion, the backbone of the synapse: "vertebrate" and "invertebrate" perspectives. Cold Spring Harb Perspect Biol 2010; 1:a003079. [PMID: 20066100 DOI: 10.1101/cshperspect.a003079] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Synapses are asymmetric intercellular junctions that mediate neuronal communication. The number, type, and connectivity patterns of synapses determine the formation, maintenance, and function of neural circuitries. The complexity and specificity of synaptogenesis relies upon modulation of adhesive properties, which regulate contact initiation, synapse formation, maturation, and functional plasticity. Disruption of adhesion may result in structural and functional imbalance that may lead to neurodevelopmental diseases, such as autism, or neurodegeneration, such as Alzheimer's disease. Therefore, understanding the roles of different adhesion protein families in synapse formation is crucial for unraveling the biology of neuronal circuit formation, as well as the pathogenesis of some brain disorders. The present review summarizes some of the knowledge that has been acquired in vertebrate and invertebrate genetic model organisms.
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Affiliation(s)
- Nikolaos Giagtzoglou
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas 77030, USA.
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37
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Chen L, Zhou S. "CRASH"ing with the worm: insights into L1CAM functions and mechanisms. Dev Dyn 2010; 239:1490-501. [PMID: 20225255 DOI: 10.1002/dvdy.22269] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The L1 family of cell adhesion molecules (L1CAMs) in vertebrates has long been studied for its roles in nervous system development and function. Members of this family have been associated with distinct neurological disorders that include CRASH, autism, 3p syndrome, and schizophrenia. The conservation of L1CAMs in Drosophila and Caenorhabditis elegans allows the opportunity to take advantage of these simple model organisms and their accessible genetic manipulations to dissect L1CAM functions and mechanisms of action. This review summarizes the discoveries of L1CAMs made in C. elegans, showcasing this simple model organism as a powerful system to uncover L1CAM mechanisms and roles in healthy and diseased states.
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Affiliation(s)
- Lihsia Chen
- Department of Genetics, Cell Biology, and Development, Developmental Biology Center, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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Gavert N, Ben-Shmuel A, Lemmon V, Brabletz T, Ben-Ze'ev A. Nuclear factor-kappaB signaling and ezrin are essential for L1-mediated metastasis of colon cancer cells. J Cell Sci 2010; 123:2135-43. [PMID: 20501702 DOI: 10.1242/jcs.069542] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Hyperactivation of beta-catenin-T-cell-factor (TCF)-regulated gene transcription is a hallmark of colorectal cancer (CRC). The cell-neural adhesion molecule L1CAM (hereafter referred to as L1) is a target of beta-catenin-TCF, exclusively expressed at the CRC invasive front in humans. L1 overexpression in CRC cells increases cell growth and motility, and promotes liver metastasis. Genes induced by L1 are also expressed in human CRC tissue but the mechanisms by which L1 confers metastasis are still unknown. We found that signaling by the nuclear factor kappaB (NF-kappaB) is essential, because inhibition of signaling by the inhibitor of kappaB super repressor (IkappaB-SR) blocked L1-mediated metastasis. Overexpression of the NF-kappaB p65 subunit was sufficient to increase CRC cell proliferation, motility and metastasis. Binding of the L1 cytodomain to ezrin - a cytoskeleton-crosslinking protein - is necessary for metastasis because when binding to L1 was interrupted or ezrin gene expression was suppressed with specific shRNA, metastasis did not occur. L1 and ezrin bound to and mediated the phosphorylation of IkappaB. We also observed a complex containing IkappaB, L1 and ezrin in the juxtamembrane region of CRC cells. Furthermore, we found that L1, ezrin and phosphorylated p65 are co-expressed at the invasive front in human CRC tissue, indicating that L1-mediated activation of NF-kappaB signaling involving ezrin is a major route of CRC progression.
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Affiliation(s)
- Nancy Gavert
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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Nakamura Y, Lee S, Haddox CL, Weaver EJ, Lemmon VP. Role of the cytoplasmic domain of the L1 cell adhesion molecule in brain development. J Comp Neurol 2010; 518:1113-32. [PMID: 20127821 DOI: 10.1002/cne.22267] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Mutations in the human L1CAM gene cause X-linked hydrocephalus and MASA (Mental retardation, Aphasia, Shuffling gait, Adducted thumbs) syndrome. In vitro studies have shown that the L1 cytoplasmic domain (L1CD) is involved in L1 trafficking, neurite branching, signaling, and interactions with the cytoskeleton. L1cam knockout (L1(KO)) mice have hydrocephalus, a small cerebellum, hyperfasciculation of corticothalamic tracts, and abnormal peripheral nerves. To explore the function of the L1CD, we made three new mice lines in which different parts of the L1CD have been altered. In all mutant lines L1 protein is expressed and transported into the axon. Interestingly, these new L1CD mutant lines display normal brain morphology. However, the expression of L1 protein in the adult is dramatically reduced in the two L1CD mutant lines that lack the ankyrin-binding region and they show defects in motor function. Therefore, the L1CD is not responsible for the major defects observed in L1(KO) mice, yet it is required for continued L1 protein expression and motor function in the adult.
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Affiliation(s)
- Yukiko Nakamura
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida 33136, USA
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40
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A chemical screen identifies novel compounds that overcome glial-mediated inhibition of neuronal regeneration. J Neurosci 2010; 30:4693-706. [PMID: 20357120 DOI: 10.1523/jneurosci.0302-10.2010] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A major barrier to regeneration of CNS axons is the presence of growth-inhibitory proteins associated with myelin and the glial scar. To identify chemical compounds with the ability to overcome the inhibition of regeneration, we screened a novel triazine library, based on the ability of compounds to increase neurite outgrowth from cerebellar neurons on inhibitory myelin substrates. The screen produced four "hit compounds," which act with nanomolar potency on several different neuronal types and on several distinct substrates relevant to glial inhibition. Moreover, the compounds selectively overcome inhibition rather than promote growth in general. The compounds do not affect neuronal cAMP levels, PKC activity, or EGFR (epidermal growth factor receptor) activation. Interestingly, one of the compounds alters microtubule dynamics and increases microtubule density in both fibroblasts and neurons. This same compound promotes regeneration of dorsal column axons after acute lesions and potentiates regeneration of optic nerve axons after nerve crush in vivo. These compounds should provide insight into the mechanisms through which glial-derived inhibitors of regeneration act, and could lead to the development of novel therapies for CNS injury.
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Moon MS, Gomez TM. Balanced Vav2 GEF activity regulates neurite outgrowth and branching in vitro and in vivo. Mol Cell Neurosci 2010; 44:118-28. [PMID: 20298788 DOI: 10.1016/j.mcn.2010.03.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 02/25/2010] [Accepted: 03/02/2010] [Indexed: 01/25/2023] Open
Abstract
We have investigated the role of Vav2, a reported Rac1/Cdc42 GEF, on the development of Xenopus spinal neurons in vitro and in vivo. Both gain and loss of Vav2 function inhibited the rate neurite extension on laminin (LN), while only GFP-Vav2 over-expression enhanced process formation and branching. Vav2 over-expression protected neurons from RhoA-mediated growth cone collapse, similar to constitutively active Rac1, suggesting that Vav2 activates Rac1 in spinal neurons. Enhanced branching on LN required both Vav2 GEF activity and N-terminal tyrosine residues, but protection from RhoA-mediated collapse only required GEF activity. Interestingly, wild-type spinal neurons exhibited increased branching on the cell adhesion molecule L1, which required Vav2 GEF function, but not N-terminal tyrosine residues. Finally, we find that Vav2 differentially affects the Rohon-Beard peripheral and central process extension but promotes neurite branching of commissural interneurons near the ventral midline. Together, we suggest that balanced Vav2 activity is necessary for optimal neurite outgrowth and promotes branching by targeting GEF activity to branch points.
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Affiliation(s)
- Myung-soon Moon
- Department of Anatomy, University of Wisconsin, Madison, WI 53706, USA
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Díez-Revuelta N, Velasco S, André S, Kaltner H, Kübler D, Gabius HJ, Abad-Rodríguez J. Phosphorylation of adhesion- and growth-regulatory human galectin-3 leads to the induction of axonal branching by local membrane L1 and ERM redistribution. J Cell Sci 2010; 123:671-81. [PMID: 20124415 DOI: 10.1242/jcs.058198] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Serine phosphorylation of the beta-galactoside-binding protein galectin-3 (Gal-3) impacts nuclear localization but has unknown consequences for extracellular activities. Herein, we reveal that the phosphorylated form of galectin-3 (pGal-3), adsorbed to substratum surfaces or to heparan sulphate proteoglycans, is instrumental in promoting axon branching in cultured hippocampal neurons by local actin destabilization. pGal-3 interacts with neural cell adhesion molecule L1, and enhances L1 association with Thy-1-rich membrane microdomains. Concomitantly, membrane-actin linker proteins ezrin-radixin-moesin (ERM) are recruited to the same membrane site via interaction with the intracellular domain of L1. We propose that the local regulation of the L1-ERM-actin pathway, at the level of the plasma membrane, underlies pGal-3-induced axon branching, and that galectin phosphorylation in situ could act as a molecular switch for the axon response to Gal-3.
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Affiliation(s)
- Natalia Díez-Revuelta
- Membrane Biology and Axonal Repair Laboratory. Hospital Nacional de Parapléjicos (SESCAM), Finca La Peraleda s/n, E-45071 Toledo, Spain
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43
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Tapanes-Castillo A, Weaver EJ, Smith RP, Kamei Y, Caspary T, Hamilton-Nelson KL, Slifer SH, Martin ER, Bixby JL, Lemmon VP. A modifier locus on chromosome 5 contributes to L1 cell adhesion molecule X-linked hydrocephalus in mice. Neurogenetics 2010; 11:53-71. [PMID: 19565280 PMCID: PMC2863031 DOI: 10.1007/s10048-009-0203-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 06/08/2009] [Indexed: 12/25/2022]
Abstract
Humans with L1 cell adhesion molecule (L1CAM) mutations exhibit X-linked hydrocephalus, as well as other severe neurological disorders. L1-6D mutant mice, which are homozygous for a deletion that removes the sixth immunoglobulin-like domain of L1cam, seldom display hydrocephalus on the 129/Sv background. However, the same L1-6D mutation produces severe hydrocephalus on the C57BL/6J background. To begin to understand how L1cam deficiencies result in hydrocephalus and to identify modifier loci that contribute to X-linked hydrocephalus by genetically interacting with L1cam, we conducted a genome-wide scan on F2 L1-6D mice, bred from L1-6D 129S2/SvPasCrlf and C57BL/6J mice. Linkage studies, utilizing chi-square tests and quantitative trait loci mapping techniques, were performed. Candidate modifier loci were further investigated in an extension study. Linkage was confirmed for a locus on chromosome 5, which we named L1cam hydrocephalus modifier 1 (L1hydro1), p = 4.04 X 10(-11).
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Affiliation(s)
- Alexis Tapanes-Castillo
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Lois Pope LIFE Center, Room 4-16, 1095 NW 14th Terrace, Miami, FL 33136, USA
| | - Eli J. Weaver
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Lois Pope LIFE Center, Room 4-16, 1095 NW 14th Terrace, Miami, FL 33136, USA, Department of Neuroscience, Case Western Reserve University, Cleveland, OH, USA
| | - Robin P. Smith
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Lois Pope LIFE Center, Room 4-16, 1095 NW 14th Terrace, Miami, FL 33136, USA, Neuroscience Program, University of Miami, Miami, FL, USA
| | - Yoshimasa Kamei
- Department of Neuroscience, Case Western Reserve University, Cleveland, OH, USA
| | - Tamara Caspary
- Department of Human Genetics, Emory University, Atlanta, GA, USA
| | - Kara L. Hamilton-Nelson
- Dr. John T. MacDonald Foundation, Department of Human Genetics, Miami Institute for Human Genomics, University of Miami, Miami, FL, USA
| | - Susan H. Slifer
- Dr. John T. MacDonald Foundation, Department of Human Genetics, Miami Institute for Human Genomics, University of Miami, Miami, FL, USA
| | - Eden R. Martin
- Dr. John T. MacDonald Foundation, Department of Human Genetics, Miami Institute for Human Genomics, University of Miami, Miami, FL, USA
| | - John L. Bixby
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Lois Pope LIFE Center, Room 4-16, 1095 NW 14th Terrace, Miami, FL 33136, USA, Neuroscience Program, University of Miami, Miami, FL, USA, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA, Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Vance P. Lemmon
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, Lois Pope LIFE Center, Room 4-16, 1095 NW 14th Terrace, Miami, FL 33136, USA, Department of Neuroscience, Case Western Reserve University, Cleveland, OH, USA, Neuroscience Program, University of Miami, Miami, FL, USA, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA
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Jaehrling S, Thelen K, Wolfram T, Pollerberg GE. Nanopatterns biofunctionalized with cell adhesion molecule DM-GRASP offered as cell substrate: spacing determines attachment and differentiation of neurons. NANO LETTERS 2009; 9:4115-4121. [PMID: 19694460 DOI: 10.1021/nl9023325] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The density/spacing of plasma membrane proteins is thought to be crucial for their function; clear-cut experimental evidence, however, is still rare. We examined nanopatterns biofunctionalized with cell adhesion molecule DM-GRASP with respect to their impact on neuron attachment and neurite growth. Data analysis/modeling revealed that these cellular responses improve with increasing DM-GRASP density, with the exception of one spacing which does not allow for the anchorage of a cytoskeletal protein (spectrin) to three DM-GRASP molecules.
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Affiliation(s)
- Steffen Jaehrling
- Department of Developmental Neurobiology, Institute of Zoology, University of Heidelberg, 69120 Heidelberg, Im Neuenheimer Feld 232, Germany
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45
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Gibson NJ, Tolbert LP, Oland LA. Roles of specific membrane lipid domains in EGF receptor activation and cell adhesion molecule stabilization in a developing olfactory system. PLoS One 2009; 4:e7222. [PMID: 19787046 PMCID: PMC2746287 DOI: 10.1371/journal.pone.0007222] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Accepted: 09/06/2009] [Indexed: 11/18/2022] Open
Abstract
Background Reciprocal interactions between glial cells and olfactory receptor neurons (ORNs) cause ORN axons entering the brain to sort, to fasciculate into bundles destined for specific glomeruli, and to form stable protoglomeruli in the developing olfactory system of an experimentally advantageous animal species, the moth Manduca sexta. Epidermal growth factor receptors (EGFRs) and the cell adhesion molecules (IgCAMs) neuroglian and fasciclin II are known to be important players in these processes. Methodology/Principal Findings We report in situ and cell-culture studies that suggest a role for glycosphingolipid-rich membrane subdomains in neuron-glia interactions. Disruption of these subdomains by the use of methyl-β-cyclodextrin results in loss of EGFR activation, depletion of fasciclin II in ORN axons, and loss of neuroglian stabilization in the membrane. At the cellular level, disruption leads to aberrant ORN axon trajectories, small antennal lobes, abnormal arrays of olfactory glomerul, and loss of normal glial cell migration. Conclusions/Significance We propose that glycosphingolipid-rich membrane subdomains (possible membrane rafts or platforms) are essential for IgCAM-mediated EGFR activation and for anchoring of neuroglian to the cytoskeleton, both required for normal extension and sorting of ORN axons.
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Affiliation(s)
- Nicholas J Gibson
- Arizona Research Laboratories Division of Neurobiology, University of Arizona, Tucson, Arizona, United States of America.
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46
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Giannone G, Mège RM, Thoumine O. Multi-level molecular clutches in motile cell processes. Trends Cell Biol 2009; 19:475-86. [PMID: 19716305 DOI: 10.1016/j.tcb.2009.07.001] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 07/01/2009] [Accepted: 07/02/2009] [Indexed: 01/09/2023]
Abstract
To trigger cell motility, forces generated by the cytoskeleton must be transmitted physically to the external environment through transmembrane adhesion molecules. One model put forward twenty years ago to describe this process is the molecular clutch by which a modular interface of adaptor proteins mediates a dynamic mechanical connection between the actin flow and cell adhesion complexes. Recent optical imaging experiments have identified key clutch molecules linked to specific chemical and mechanical signal transduction pathways, particularly regarding integrins in migrating cells, IgCAMs in neuronal growth cones, and cadherins at intercellular junctions. We propose here the concept of a multi-level clutch as a useful analogy to grasp the complexity of the dynamic molecular interactions involved in a panel of motile behaviors and shapes.
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Affiliation(s)
- Grégory Giannone
- CNRS UMR 5091, Institut Magendie, Université Bordeaux 2, 33077 Bordeaux, France
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47
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Yeaney NK, He M, Tang N, Malouf AT, O'Riordan MA, Lemmon V, Bearer CF. Ethanol inhibits L1 cell adhesion molecule tyrosine phosphorylation and dephosphorylation and activation of pp60(src). J Neurochem 2009; 110:779-90. [PMID: 19457108 DOI: 10.1111/j.1471-4159.2009.06143.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Fetal alcohol syndrome is a leading cause of mental retardation. The neuropathology found in patients with fetal alcohol syndrome overlaps with those with mutations in the gene for cell adhesion molecule (L1). We have previously shown that L1-mediated neurite outgrowth and L1 activation of extracellular receptor kinases 1/2 are inhibited at low concentrations of ethanol. One possible mechanism for this effect is through disruption of a tyrosine-based sorting signal, Y(1176)RSLE, on the cytoplasmic domain of L1. Our goal was to determine if ethanol inhibited the sorting signal or its phosphorylation state. Using cerebellar granule neurons and dorsal root ganglion neurons, we found that ethanol had no effect on L1 distribution to the growth cone or its ability to be expressed on the cell surface as determined by confocal microscopy. In cerebellar granule neurons, clustering of L1 resulted in increased dephosphorylation of Y(1176), increased L1 tyrosine phosphorylation, and an increase in the activation of pp60(src) as measured by immunoblot. All changes were inhibited by 25 mM ethanol. Using PP2 to inhibit pp60(src) activation resulted in inhibition of increases in L1 tyrosine and extracellular receptor kinases 1/2 phosphorylation, and Y(1176) dephosphorylation. We conclude that ethanol disrupts L1 trafficking/signaling following its expression on the surface of the growth cone, and prior to its activation of pp60(src).
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Abstract
The L1 family of CAMs (cell adhesion molecules) has long aroused the interest of researchers, but primarily the extracellular interactions of these proteins have been elucidated. More recently, attention has turned to the intracellular signalling potentiated by transmembrane proteins and the cytoplasmic proteins with which they can interact. The present review brings up to date the current body of published knowledge for the intracellular interactions of L1-CAM family proteins and the potential importance of these interactions for the mechanisms of L1-CAM action.
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Sakurai T, Gil OD, Whittard JD, Gazdoiu M, Joseph T, Wu J, Waksman A, Benson DL, Salton SR, Felsenfeld DP. Interactions between the L1 cell adhesion molecule and ezrin support traction-force generation and can be regulated by tyrosine phosphorylation. J Neurosci Res 2009; 86:2602-14. [PMID: 18478542 DOI: 10.1002/jnr.21705] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
An Ig superfamily cell-adhesion molecule, L1, forms an adhesion complex at the cell membrane containing both signaling molecules and cytoskeletal proteins. This complex mediates the transduction of extracellular signals and generates actin-mediated traction forces, both of which support axon outgrowth. The L1 cytoplasmic region binds ezrin, an adapter protein that interacts with the actin cytoskeleton. In this study, we analyzed L1-ezrin interactions in detail, assessed their role in generating traction forces by L1, and identified potential regulatory mechanisms controlling ezrin-L1 interactions. The FERM domain of ezrin binds to the juxtamembrane region of L1, demonstrated by yeast two-hybrid interaction traps and protein binding analyses in vitro. A lysine-to-leucine substitution in this domain of L1 (K1147L) shows reduced binding to the ezrin FERM domain. Additionally, in ND7 cells, the K1147L mutation inhibits retrograde movement of L1 on the cell surface that has been linked to the generation of the traction forces necessary for axon growth. A membrane-permeable peptide consisting of the juxtamembrane region of L1 that can disrupt endogenous L1-ezrin interactions inhibits neurite extension of cerebellar cells on L1 substrates. Moreover, the L1-ezrin interactions can be modulated by tyrosine phosphorylation of the L1 cytoplasmic region, namely, Y1151, possibly through Src-family kinases. Replacement of this tyrosine together with Y1176 with either aspartate or phenylalanine changes ezrin binding and alters colocalization with ezrin in ND7 cells. Collectively, these data suggest that L1-ezrin interactions mediated by the L1 juxtamembrane region are involved in traction-force generation and can be regulated by the phosphorylation of L1.
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Affiliation(s)
- Takeshi Sakurai
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York 10029, USA
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Abstract
BACKGROUND L1-cell adhesion molecule (L1-CAM) is a cell adhesion receptor of the immunoglobulin superfamily, known for its roles in nerve cell function. While originally believed to be present only in brain cells, in recent years L1-CAM has been detected in other tissues, and in a variety of cancer cells, including some common types of human cancer. OBJECTIVE/METHODS We review the prevalence of L1-CAM in human cancer, the possible mechanisms involved in L1-CAM-mediated tumorigenesis, and cancer therapies based upon L1-CAM antibody treatment. RESULTS/CONCLUSIONS In colon cancer cells, the L1-CAM gene was identified as a target of the Wnt/beta-catenin-TCF signaling pathway, and L1-CAM was exclusively detected at the invasive front of colon and ovarian cancer tissue. The expression of L1-CAM in normal and cancer cells enhanced tumorigenesis and conferred metastasis in colon cancer cells. Antibodies against the L1-CAM ectodomain severely inhibited the proliferation of a variety of cancer cells in culture and reduced tumor burden when injected into mice harboring cancer cells expressing L1-CAM. These results, in addition to the presence of L1-CAM on the cell surface and its restricted distribution in normal tissues, make it an ideal target for tumor therapy.
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Affiliation(s)
- Nancy Gavert
- Weizmann Institute of Science, Department of Molecular Cell Biology, Rehovot, Israel
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