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Mani I, Singh V. An overview of receptor endocytosis and signaling. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 194:1-18. [PMID: 36631188 DOI: 10.1016/bs.pmbts.2022.06.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Endocytosis is a cellular process which mediates receptor internalization, nutrient uptake, and the regulation of cell signaling. Microorganisms (many bacteria and viruses) and toxins also use the same process and enter the cells. Generally, endocytosis is considered in the three forms such as phagocytosis (cell eating), pinocytosis (cell drinking), and highly selective receptor-mediated endocytosis (clathrin-dependent and independent). Several endocytic routes exist in an analogous, achieving diverse functions. Most studies on endocytosis have used transformed cells in culture. To visualize the receptor internalization, trafficking, and signaling in subcellular organelles, a green fluorescent protein-tagged receptor has been utilized. It also helps to visualize the endocytosis effects in live-cell imaging. Confocal laser microscopy increases our understanding of receptor endocytosis and signaling. Site-directed mutagenesis studies demonstrated that many short-sequence motifs of the cytoplasmic domain of receptors significantly play a vital role in receptor internalization, subcellular trafficking, and signaling. However, other factors also regulate receptor internalization through clathrin-coated vesicles. Receptor endocytosis can occur through clathrin-dependent and clathrin-independent pathways. This chapter briefly discusses the internalization, trafficking, and signaling of various receptors in normal conditions. In addition, it also highlights the malfunction of the receptor in disease conditions.
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Affiliation(s)
- Indra Mani
- Department of Microbiology, Gargi College, University of Delhi, New Delhi, India.
| | - Vijai Singh
- Department of Biosciences, School of Science, Indrashil University, Rajpur, Mehsana, Gujarat, India
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Mani I, Singh V. Receptor biology: Challenges and opportunities. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 196:337-349. [PMID: 36813364 DOI: 10.1016/bs.pmbts.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Receptor biology provides a great opportunity to understand the ligand-receptor signaling involved in health and disease processes. Receptor endocytosis and signaling play a vital role in health conditions. Receptor-based signaling is the main form of communication between cells and cells with the environment. However, if any irregularities happen during these events, the consequences of pathophysiological conditions occur. Various methods are utilized to know structure, function, and regulation of receptor proteins. Further, live-cell imaging and genetic manipulations have aided in the understanding of receptor internalization, subcellular trafficking, signaling, metabolic degradation, etc. Understanding the genetics, biochemistry, and physiology of receptors and ligands is very helpful to explore various aspects such as prognosis, diagnosis, and treatment of disease. However, there are enormous challenges that exist to explore receptor biology further. This chapter briefly discusses the current challenges and emerging opportunities of receptor biology.
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Affiliation(s)
- Indra Mani
- Department of Microbiology, Gargi College, University of Delhi, New Delhi, India.
| | - Vijai Singh
- Department of Biosciences, School of Science, Indrashil University, Rajpur, Mehsana, Gujarat, India
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Wu HF, Yu W, Saito-Diaz K, Huang CW, Carey J, Lefcort F, Hart GW, Liu HX, Zeltner N. Norepinephrine transporter defects lead to sympathetic hyperactivity in Familial Dysautonomia models. Nat Commun 2022; 13:7032. [PMID: 36396637 PMCID: PMC9671909 DOI: 10.1038/s41467-022-34811-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 11/08/2022] [Indexed: 11/19/2022] Open
Abstract
Familial dysautonomia (FD), a rare neurodevelopmental and neurodegenerative disorder affects the sympathetic and sensory nervous system. Although almost all patients harbor a mutation in ELP1, it remains unresolved exactly how function of sympathetic neurons (symNs) is affected; knowledge critical for understanding debilitating disease hallmarks, including cardiovascular instability or dysautonomic crises, that result from dysregulated sympathetic activity. Here, we employ the human pluripotent stem cell (hPSC) system to understand symN disease mechanisms and test candidate drugs. FD symNs are intrinsically hyperactive in vitro, in cardiomyocyte co-cultures, and in animal models. We report reduced norepinephrine transporter expression, decreased intracellular norepinephrine (NE), decreased NE re-uptake, and excessive extracellular NE in FD symNs. SymN hyperactivity is not a direct ELP1 mutation result, but may connect to NET via RAB proteins. We found that candidate drugs lowered hyperactivity independent of ELP1 modulation. Our findings may have implications for other symN disorders and may allow future drug testing and discovery.
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Affiliation(s)
- Hsueh-Fu Wu
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - Wenxin Yu
- Regenerative Bioscience Center, Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, USA
| | - Kenyi Saito-Diaz
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA
| | - Chia-Wei Huang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Joseph Carey
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Frances Lefcort
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Gerald W Hart
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Hong-Xiang Liu
- Regenerative Bioscience Center, Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, USA
| | - Nadja Zeltner
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA.
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.
- Department of Cellular Biology, University of Georgia, Athens, GA, USA.
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Tolman Z, Chaverra M, George L, Lefcort F. Elp1 is required for development of visceral sensory peripheral and central circuitry. Dis Model Mech 2022; 15:275184. [PMID: 35481599 PMCID: PMC9187870 DOI: 10.1242/dmm.049274] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 04/20/2022] [Indexed: 11/23/2022] Open
Abstract
Cardiovascular instability and a blunted respiratory drive in hypoxic conditions are hallmark features of the genetic sensory and autonomic neuropathy, familial dysautonomia (FD). FD results from a mutation in the gene ELP1, the encoded protein of which is a scaffolding subunit of the six-subunit Elongator complex. In mice, we and others have shown that Elp1 is essential for the normal development of neural crest-derived dorsal root ganglia sensory neurons. Whether Elp1 is also required for development of ectodermal placode-derived visceral sensory receptors, which are required for normal baroreception and chemosensory responses, has not been investigated. Using mouse models for FD, we here show that the entire circuitry underlying baroreception and chemoreception is impaired due to a requirement for Elp1 in the visceral sensory neuron ganglia, as well as for normal peripheral target innervation, and in their central nervous system synaptic partners in the medulla. Thus, Elp1 is required in both placode- and neural crest-derived sensory neurons, and its reduction aborts the normal development of neuronal circuitry essential for autonomic homeostasis and interoception. This article has an associated First Person interview with the first author of the paper. Summary: Our data indicate that Elp1 is required in both placode- and neural crest-derived sensory neurons, and that it exerts comparable effects, including survival, axonal morphology and target innervation in both lineages.
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Affiliation(s)
- Zariah Tolman
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Marta Chaverra
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Lynn George
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA.,Department of Biological and Physical Sciences, Montana State University Billings, Billings, MT 59101, USA
| | - Frances Lefcort
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
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Leonard CE, Quiros J, Lefcort F, Taneyhill LA. Loss of Elp1 disrupts trigeminal ganglion neurodevelopment in a model of familial dysautonomia. eLife 2022; 11:71455. [PMID: 35713404 PMCID: PMC9273214 DOI: 10.7554/elife.71455] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 06/17/2022] [Indexed: 01/28/2023] Open
Abstract
Familial dysautonomia (FD) is a sensory and autonomic neuropathy caused by mutations in elongator complex protein 1 (ELP1). FD patients have small trigeminal nerves and impaired facial pain and temperature perception. These signals are relayed by nociceptive neurons in the trigeminal ganglion, a structure that is composed of both neural crest- and placode-derived cells. Mice lacking Elp1 in neural crest derivatives ('Elp1 CKO') are born with small trigeminal ganglia, suggesting Elp1 is important for trigeminal ganglion development, yet the function of Elp1 in this context is unknown. We demonstrate that Elp1, expressed in both neural crest- and placode-derived neurons, is not required for initial trigeminal ganglion formation. However, Elp1 CKO trigeminal neurons exhibit abnormal axon outgrowth and deficient target innervation. Developing nociceptors expressing the receptor TrkA undergo early apoptosis in Elp1 CKO, while TrkB- and TrkC-expressing neurons are spared, indicating Elp1 supports the target innervation and survival of trigeminal nociceptors. Furthermore, we demonstrate that specific TrkA deficits in the Elp1 CKO trigeminal ganglion reflect the neural crest lineage of most TrkA neurons versus the placodal lineage of most TrkB and TrkC neurons. Altogether, these findings explain defects in cranial gangliogenesis that may lead to loss of facial pain and temperature sensation in FD.
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Affiliation(s)
- Carrie E Leonard
- Department of Avian and Animal Sciences, University of Maryland, College ParkCollege ParkUnited States
| | - Jolie Quiros
- Department of Avian and Animal Sciences, University of Maryland, College ParkCollege ParkUnited States
| | - Frances Lefcort
- Department of Microbiology and Cell Biology, Montana State UniversityBozemanUnited States
| | - Lisa A Taneyhill
- Department of Avian and Animal Sciences, University of Maryland, College ParkCollege ParkUnited States
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Chen WT, Tseng HY, Jiang CL, Lee CY, Chi P, Chen LY, Lo KY, Wang IC, Lin FJ. Elp1 facilitates RAD51-mediated homologous recombination repair via translational regulation. J Biomed Sci 2021; 28:81. [PMID: 34819065 PMCID: PMC8613991 DOI: 10.1186/s12929-021-00773-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 11/02/2021] [Indexed: 11/25/2022] Open
Abstract
Background RAD51-dependent homologous recombination (HR) is one of the most important pathways for repairing DNA double-strand breaks (DSBs), and its regulation is crucial to maintain genome integrity. Elp1 gene encodes IKAP/ELP1, a core subunit of the Elongator complex, which has been implicated in translational regulation. However, how ELP1 contributes to genome maintenance is unclear. Methods To investigate the function of Elp1, Elp1-deficient mouse embryonic fibroblasts (MEFs) were generated. Metaphase chromosome spreading, immunofluorescence, and comet assays were used to access chromosome abnormalities and DSB formation. Functional roles of Elp1 in MEFs were evaluated by cell viability, colony forming capacity, and apoptosis assays. HR-dependent DNA repair was assessed by reporter assay, immunofluorescence, and western blot. Polysome profiling was used to evaluate translational efficiency. Differentially expressed proteins and signaling pathways were identified using a label-free liquid chromatography–tandem mass spectrometry (LC–MS/MS) proteomics approach. Results Here, we report that Elp1 depletion enhanced genomic instability, manifested as chromosome breakage and genotoxic stress-induced genomic DNA fragmentation upon ionizing radiation (IR) exposure. Elp1-deficient cells were hypersensitive to DNA damage and exhibited impaired cell proliferation and defective HR repair. Moreover, Elp1 depletion reduced the formation of IR-induced RAD51 foci and decreased RAD51 protein levels. Polysome profiling analysis revealed that ELP1 regulated RAD51 expression by promoting its translation in response to DNA damage. Notably, the requirement for ELP1 in DSB repair could be partially rescued in Elp1-deficient cells by reintroducing RAD51, suggesting that Elp1-mediated HR-directed repair of DSBs is RAD51-dependent. Finally, using proteome analyses, we identified several proteins involved in cancer pathways and DNA damage responses as being differentially expressed upon Elp1 depletion. Conclusions Our study uncovered a molecular mechanism underlying Elp1-mediated regulation of HR activity and provides a novel link between translational regulation and genome stability. Supplementary Information The online version contains supplementary material available at 10.1186/s12929-021-00773-z.
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Affiliation(s)
- Wei-Ting Chen
- Department of Biochemical Science and Technology, National Taiwan University, No.1, Sec.4, Roosevelt Rd., Taipei, 10617, Taiwan
| | - Huan-Yi Tseng
- Department of Biochemical Science and Technology, National Taiwan University, No.1, Sec.4, Roosevelt Rd., Taipei, 10617, Taiwan
| | - Chung-Lin Jiang
- Department of Biochemical Science and Technology, National Taiwan University, No.1, Sec.4, Roosevelt Rd., Taipei, 10617, Taiwan
| | - Chih-Ying Lee
- Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617, Taiwan
| | - Peter Chi
- Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617, Taiwan.,Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Liuh-Yow Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Kai-Yin Lo
- Department of Agricultural Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - I-Ching Wang
- Institute of Biotechnology, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Fu-Jung Lin
- Department of Biochemical Science and Technology, National Taiwan University, No.1, Sec.4, Roosevelt Rd., Taipei, 10617, Taiwan. .,Research Center for Development Biology and Regenerative Medicine, National Taiwan University, Taipei, 10617, Taiwan.
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Abstract
The sympathetic nervous system prepares the body for 'fight or flight' responses and maintains homeostasis during daily activities such as exercise, eating a meal or regulation of body temperature. Sympathetic regulation of bodily functions requires the establishment and refinement of anatomically and functionally precise connections between postganglionic sympathetic neurons and peripheral organs distributed widely throughout the body. Mechanistic studies of key events in the formation of postganglionic sympathetic neurons during embryonic and early postnatal life, including axon growth, target innervation, neuron survival, and dendrite growth and synapse formation, have advanced the understanding of how neuronal development is shaped by interactions with peripheral tissues and organs. Recent progress has also been made in identifying how the cellular and molecular diversity of sympathetic neurons is established to meet the functional demands of peripheral organs. In this Review, we summarize current knowledge of signalling pathways underlying the development of the sympathetic nervous system. These findings have implications for unravelling the contribution of sympathetic dysfunction stemming, in part, from developmental perturbations to the pathophysiology of peripheral neuropathies and cardiovascular and metabolic disorders.
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Ghosh S, Tourtellotte WG. The Complex Clinical and Genetic Landscape of Hereditary Peripheral Neuropathy. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2021; 16:487-509. [PMID: 33497257 DOI: 10.1146/annurev-pathol-030320-100822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Hereditary peripheral neuropathy (HPN) is a complex group of neurological disorders caused by mutations in genes expressed by neurons and Schwann cells. The inheritance of a single mutation or multiple mutations in several genes leads to disease phenotype. Patients exhibit symptoms during development, at an early age or later in adulthood. Most of the mechanistic understanding about these neuropathies comes from animal models and histopathological analyses of postmortem human tissues. Diagnosis is often very complex due to the heterogeneity and overlap in symptoms and the frequent overlap between various genes and different mutations they possess. Some symptoms in HPN are common through different subtypes such as axonal degeneration, demyelination, and loss of motor and sensory neurons, leading to similar physiologic abnormalities. Recent advances in gene-targeted therapies, genetic engineering, and next-generation sequencing have augmented our understanding of the underlying pathogenetic mechanisms of HPN.
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Affiliation(s)
- Soumitra Ghosh
- Department of Pathology and Laboratory Medicine, Neurology, and Neurological Surgery, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA;
| | - Warren G Tourtellotte
- Department of Pathology and Laboratory Medicine, Neurology, and Neurological Surgery, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA;
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Kaplan DR, Mobley WC. (H)Elping nerve growth factor: Elp1 inhibits TrkA's phosphatase to maintain retrograde signaling. J Clin Invest 2021; 130:2195-2198. [PMID: 32281945 DOI: 10.1172/jci136162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Nerve growth factor (NGF) regulates many aspects of neuronal biology by retrogradely propagating signals along axons to the targets of those axons. How this occurs when axons contain a plethora of proteins that can silence those signals has long perplexed the neurotrophin field. In this issue of the JCI, Li et al. suggest an answer to this vexing problem, while exploring why the Elp1 gene that is mutated in familial dysautonomia (FD) causes peripheral neuropathy. They describe a distinctive function of Elp1 as a protein that is required to sustain NGF signaling by blocking the activity of its phosphatase that shuts off those signals. This finding helps explain the innervation deficits prominent in FD and reveals a unique role for Elp1 in the regulation of NGF-dependent TrkA activity.
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Affiliation(s)
- David R Kaplan
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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Ghosh S, Li L, Tourtellotte WG. Retrograde nerve growth factor signaling abnormalities and the pathogenesis of familial dysautonomia. Neural Regen Res 2021; 16:1795-1796. [PMID: 33510081 PMCID: PMC8328778 DOI: 10.4103/1673-5374.306081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Soumitra Ghosh
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Lin Li
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Warren G Tourtellotte
- Department of Pathology and Laboratory Medicine; Department of Neurology; Department of Neurosurgery; Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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Research Highlights. Transplantation 2020. [DOI: 10.1097/tp.0000000000003422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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