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DePew AT, Bruckner JJ, O'Connor-Giles KM, Mosca TJ. Neuronal LRP4 directs the development, maturation and cytoskeletal organization of Drosophila peripheral synapses. Development 2024; 151:dev202517. [PMID: 38738619 PMCID: PMC11190576 DOI: 10.1242/dev.202517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 05/02/2024] [Indexed: 05/14/2024]
Abstract
Synaptic development requires multiple signaling pathways to ensure successful connections. Transmembrane receptors are optimally positioned to connect the synapse and the rest of the neuron, often acting as synaptic organizers to synchronize downstream events. One such organizer, the LDL receptor-related protein LRP4, is a cell surface receptor that has been most well-studied postsynaptically at mammalian neuromuscular junctions. Recent work, however, identified emerging roles, but how LRP4 acts as a presynaptic organizer and the downstream mechanisms of LRP4 are not well understood. Here, we show that LRP4 functions presynaptically at Drosophila neuromuscular synapses, acting in motoneurons to instruct pre- and postsynaptic development. Loss of presynaptic LRP4 results in multiple defects, impairing active zone organization, synapse growth, physiological function, microtubule organization, synaptic ultrastructure and synapse maturation. We further demonstrate that LRP4 promotes most aspects of presynaptic development via a downstream SR-protein kinase, SRPK79D. These data demonstrate a function for presynaptic LRP4 as a peripheral synaptic organizer, highlight a downstream mechanism conserved with its CNS function in Drosophila, and underscore previously unappreciated but important developmental roles for LRP4 in cytoskeletal organization, synapse maturation and active zone organization.
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Affiliation(s)
- Alison T. DePew
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Joseph J. Bruckner
- Cell and Molecular Biology Training Program, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Kate M. O'Connor-Giles
- Department of Neuroscience, Brown University, Providence, RI 02912, USA
- Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Timothy J. Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
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2
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DePew AT, Bruckner JJ, O’Connor-Giles KM, Mosca TJ. Neuronal LRP4 directs the development, maturation, and cytoskeletal organization of peripheral synapses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.03.564481. [PMID: 37961323 PMCID: PMC10635100 DOI: 10.1101/2023.11.03.564481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Synapse development requires multiple signaling pathways to accomplish the myriad of steps needed to ensure a successful connection. Transmembrane receptors on the cell surface are optimally positioned to facilitate communication between the synapse and the rest of the neuron and often function as synaptic organizers to synchronize downstream signaling events. One such organizer, the LDL receptor-related protein LRP4, is a cell surface receptor most well-studied postsynaptically at mammalian neuromuscular junctions. Recent work, however, has identified emerging roles for LRP4 as a presynaptic molecule, but how LRP4 acts as a presynaptic organizer, what roles LRP4 plays in organizing presynaptic biology, and the downstream mechanisms of LRP4 are not well understood. Here we show that LRP4 functions presynaptically at Drosophila neuromuscular synapses, acting in motor neurons to instruct multiple aspects of pre- and postsynaptic development. Loss of presynaptic LRP4 results in a range of developmental defects, impairing active zone organization, synapse growth, physiological function, microtubule organization, synaptic ultrastructure, and synapse maturation. We further demonstrate that LRP4 promotes most aspects of presynaptic development via a downstream SR-protein kinase, SRPK79D. SRPK79D overexpression suppresses synaptic defects associated with loss of lrp4. These data demonstrate a function for LRP4 as a peripheral synaptic organizer acting presynaptically, highlight a downstream mechanism conserved with its CNS function, and indicate previously unappreciated roles for LRP4 in cytoskeletal organization, synapse maturation, and active zone organization, underscoring its developmental importance.
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Affiliation(s)
- Alison T. DePew
- Dept. of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107 USA
| | - Joseph J. Bruckner
- Cell and Molecular Biology Training Program, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Kate M. O’Connor-Giles
- Department of Neuroscience, Brown University, Providence, RI 02912 USA
- Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Timothy J. Mosca
- Dept. of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107 USA
- Lead Contact
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3
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Santos PF, Fazendeiro B, Luca FC, Ambrósio AF, Léger H. The NDR/LATS protein kinases in neurobiology: Key regulators of cell proliferation, differentiation and migration in the ocular and central nervous system. Eur J Cell Biol 2023; 102:151333. [PMID: 37327741 DOI: 10.1016/j.ejcb.2023.151333] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 06/07/2023] [Accepted: 06/09/2023] [Indexed: 06/18/2023] Open
Abstract
Nuclear Dbf2-related (NDR) kinases are a subgroup of evolutionarily conserved AGC protein kinases that regulate various aspects of cell growth and morphogenesis. There are 4 NDR protein kinases in mammals, LATS1, LATS2 and STTK8/NDR1, STK38L/NDR2 protein kinases. LATS1 and 2 are core components of the well-studied Hippo pathway, which play a critical role in the regulation of cell proliferation, differentiation, and cell migration via YAP/TAZ transcription factor. The Hippo pathways play an important role in nervous tissue development and homeostasis, especially with regard to the central nervous system (CNS) and the ocular system. The ocular system is a very complex system generated by the interaction in a very tightly coordinated manner of numerous and diverse developing tissues, such as, but not limited to choroidal and retinal blood vessels, the retinal pigmented epithelium and the retina, a highly polarized neuronal tissue. The retina development and maintenance require precise and coordinated regulation of cell proliferation, cell death, migration, morphogenesis, synaptic connectivity, and balanced homeostasis. This review highlights the emerging roles of NDR1 and NDR2 kinases in the regulation of retinal/neuronal function and homeostasis via a noncanonical branch of the Hippo pathway. We highlight a potential role of NDR1 and NDR2 kinases in regulating neuronal inflammation and as potential therapeutic targets for the treatment of neuronal diseases.
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Affiliation(s)
- Paulo F Santos
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University Coimbra, Azinhaga Santa Comba, Celas, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), Faculty of Medicine, University Coimbra, Rua Larga, 3004-504 Coimbra, Portugal; Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal; Department of Life Sciences, University Coimbra, CC Martim de Freitas, 3000-456 Coimbra, Portugal
| | - Beatriz Fazendeiro
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University Coimbra, Azinhaga Santa Comba, Celas, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), Faculty of Medicine, University Coimbra, Rua Larga, 3004-504 Coimbra, Portugal; Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
| | - Francis C Luca
- Department of Biomedical Sciences, University of Pennsylvania School of Veterinary Medicine, 3800 Spruce Street, Philadelphia, PA 19104, United States
| | - António Francisco Ambrósio
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University Coimbra, Azinhaga Santa Comba, Celas, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), Faculty of Medicine, University Coimbra, Rua Larga, 3004-504 Coimbra, Portugal; Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Azinhaga Santa Comba, Celas, 3000-548 Coimbra, Portugal
| | - Hélène Léger
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University Coimbra, Azinhaga Santa Comba, Celas, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), Faculty of Medicine, University Coimbra, Rua Larga, 3004-504 Coimbra, Portugal; Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal.
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Zheng K, Ren Z, Wang Y. Serine-arginine protein kinases and their targets in viral infection and their inhibition. Cell Mol Life Sci 2023; 80:153. [PMID: 37198350 PMCID: PMC10191411 DOI: 10.1007/s00018-023-04808-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/10/2023] [Accepted: 05/12/2023] [Indexed: 05/19/2023]
Abstract
Accumulating evidence has consolidated the interaction between viral infection and host alternative splicing. Serine-arginine (SR) proteins are a class of highly conserved splicing factors critical for the spliceosome maturation, alternative splicing and RNA metabolism. Serine-arginine protein kinases (SRPKs) are important kinases that specifically phosphorylate SR proteins to regulate their distribution and activities in the central pre-mRNA splicing and other cellular processes. In addition to the predominant SR proteins, other cytoplasmic proteins containing a serine-arginine repeat domain, including viral proteins, have been identified as substrates of SRPKs. Viral infection triggers a myriad of cellular events in the host and it is therefore not surprising that viruses explore SRPKs-mediated phosphorylation as an important regulatory node in virus-host interactions. In this review, we briefly summarize the regulation and biological function of SRPKs, highlighting their involvement in the infection process of several viruses, such as viral replication, transcription and capsid assembly. In addition, we review the structure-function relationships of currently available inhibitors of SRPKs and discuss their putative use as antivirals against well-characterized viruses or newly emerging viruses. We also highlight the viral proteins and cellular substrates targeted by SRPKs as potential antiviral therapeutic candidates.
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Affiliation(s)
- Kai Zheng
- School of Pharmacy, Shenzhen University Medical School, Shenzhen, 518055, China.
| | - Zhe Ren
- Institute of Biomedicine, College of Life Science and Technology, Guangdong Province Key Laboratory of Bioengineering Medicine, Key Laboratory of Innovative Technology Research On Natural Products and Cosmetics Raw Materials, Jinan University, Guangzhou, 510632, China
| | - Yifei Wang
- Institute of Biomedicine, College of Life Science and Technology, Guangdong Province Key Laboratory of Bioengineering Medicine, Key Laboratory of Innovative Technology Research On Natural Products and Cosmetics Raw Materials, Jinan University, Guangzhou, 510632, China
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Mercier J, Nagengast AA, DiAngelo JR. The role of SR protein kinases in regulating lipid storage in the Drosophila fat body. Biochem Biophys Res Commun 2023; 649:10-15. [PMID: 36738578 DOI: 10.1016/j.bbrc.2023.01.093] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 01/28/2023] [Indexed: 01/31/2023]
Abstract
The survival of animals during periods of limited nutrients is dependent on the organism's ability to store lipids during times of nutrient abundance. However, the increased availability of food in modern western society has led to an excess storage of lipids resulting in metabolic diseases. To better understand the genes involved in regulating lipid storage, genome-wide RNAi screens were performed in cultured Drosophila cells and one group of genes identified includes mRNA splicing factor genes. Our lab has previously shown that a group of splicing factors important for intron/exon border recognition known as SR proteins are involved in controlling lipid storage in Drosophila; however, how these SR proteins are regulated to control lipid storage is not fully understood. Here, we focus on two SR protein kinases (SRPKs) in Drosophila: SRPK and SRPK79D. Decreasing the expression of these genes specifically in the adult fat body using RNAi resulted in lower levels of triglycerides and this is due to a decrease in the amount of fat stored per cell, despite having more fat cells, when compared to control flies. Decreasing SRPK and SRPK79D levels in the fat body leads to altered splicing of the β-oxidation gene, carnitine palmitoyltransferase 1 (CPT1), resulting in increased production of a more active enzyme, which would increase lipid breakdown and be consistent with the lean phenotype observed in these flies. In addition, flies with decreased SRPK and SRPK79D levels in their fat bodies eat less, which may also contribute to the decreased triglyceride phenotype. Together, these findings provide evidence to support that lipid storage is controlled by the phosphorylation of factors involved in mRNA splicing.
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Affiliation(s)
| | - Alexis A Nagengast
- Departments of Chemistry and Biochemistry, Widener University, Chester, PA, USA.
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Seo MH, Yeo S. Association Between Decreased Srpk3 Expression and Increased Substantia Nigra Alpha-Synuclein Level in an MPTP-Induced Parkinson's Disease Mouse Model. Mol Neurobiol 2023; 60:780-788. [PMID: 36369636 DOI: 10.1007/s12035-022-03104-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 10/25/2022] [Indexed: 11/13/2022]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disorder and is caused by the loss of dopaminergic neurons in the substantia nigra (SN). However, the reason for the death of dopaminergic neurons remains unclear. An increase in α-synuclein (α-syn) expression is an important factor in the pathogenesis of PD. In the current study, we investigated the association between serine/arginine-rich protein-specific kinase 3 (Srpk3) and PD in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model and in SH-SY5Y cells treated with 1-methyl-4-phenylpyridinium (MPP+). Srpk3 expression was significantly downregulated, while tyrosine hydroxylase (TH) expression decreased and α-syn expression increased after 4 weeks of MPTP treatment. Dopaminergic cell reduction and α-syn expression increase were demonstrated by Srpk3 expression inhibition by siRNA in SH-SY5Y cells. Moreover, a decrease in Srpk3 expression upon siRNA treatment promoted dopaminergic cell reduction and α-syn expression increase in SH-SY5Y cells treated with MPP+ . These results suggested that Srpk3 expression decrease due to Srpk3 siRNA caused both TH level decrease and α-syn expression increase. This raises new possibilities for studying how Srpk3 controls dopaminergic cells and α-syn expression, which may be related to PD pathogenesis. Our results provide an avenue for understanding the role of Srpk3 in dopaminergic cell loss and α-syn upregulation in SN. Furthermore, this study supports a therapeutic possibility for PD in that the maintenance of Srpk3 expression inhibits dopaminergic cell reduction.
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Affiliation(s)
- Min Hyung Seo
- Department of Meridian and Acupoint, College of Korean Medicine, Sangji University, #83 Sangjidae-Gil, Wonju, 26339, Gangwon-Do, Republic of Korea
| | - Sujung Yeo
- Department of Meridian and Acupoint, College of Korean Medicine, Sangji University, #83 Sangjidae-Gil, Wonju, 26339, Gangwon-Do, Republic of Korea. .,Research Institute of Korean Medicine, Sangji University, Wonju, 26339, Republic of Korea.
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7
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Poddar MK, Banerjee S, Chakraborty A, Dutta D. Metabolic disorder in Alzheimer's disease. Metab Brain Dis 2021; 36:781-813. [PMID: 33638805 DOI: 10.1007/s11011-021-00673-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 01/14/2021] [Indexed: 12/21/2022]
Abstract
Alzheimer's disease (AD), a well known aging-induced neurodegenerative disease is related to amyloid proteinopathy. This proteinopathy occurs due to abnormalities in protein folding, structure and thereby its function in cells. The root cause of such kind of proteinopathy and its related neurodegeneration is a disorder in metabolism, rather metabolomics of the major as well as minor nutrients. Metabolomics is the most relevant "omics" platform that offers a great potential for the diagnosis and prognosis of neurodegenerative diseases as an individual's metabolome. In recent years, the research on such kinds of neurodegenerative diseases, especially aging-related disorders is broadened its scope towards metabolic function. Different neurotransmitter metabolisms are also involved with AD and its associated neurodegeneration. The genetic and epigenetic backgrounds are also noteworthy. In this review, the physiological changes of AD in relation to its corresponding biochemical, genetic and epigenetic involvements including its (AD) therapeutic aspects are discussed.
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Affiliation(s)
- Mrinal K Poddar
- Department of Pharmaceutical Technology, Jadavpur University, 188, Raja S. C. Mallick Road, Kolkata, 700032, India.
| | - Soumyabrata Banerjee
- Department of Pharmaceutical Technology, Jadavpur University, 188, Raja S. C. Mallick Road, Kolkata, 700032, India
- Departrment of Psychology, Neuroscience Program, Field Neurosciences Institute Research Laboratory for Restorative Neurology, Central Michigan University, Mount Pleasant, MI, 48859, USA
| | - Apala Chakraborty
- Department of Pharmaceutical Technology, Jadavpur University, 188, Raja S. C. Mallick Road, Kolkata, 700032, India
| | - Debasmita Dutta
- Department of Pharmaceutical Technology, Jadavpur University, 188, Raja S. C. Mallick Road, Kolkata, 700032, India
- Department of Coatings and Polymeric Materials, North Dakota State University, Fargo, ND, 58102, USA
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DePew AT, Mosca TJ. Conservation and Innovation: Versatile Roles for LRP4 in Nervous System Development. J Dev Biol 2021; 9:9. [PMID: 33799485 PMCID: PMC8006230 DOI: 10.3390/jdb9010009] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/09/2021] [Accepted: 03/11/2021] [Indexed: 02/07/2023] Open
Abstract
As the nervous system develops, connections between neurons must form to enable efficient communication. This complex process of synaptic development requires the coordination of a series of intricate mechanisms between partner neurons to ensure pre- and postsynaptic differentiation. Many of these mechanisms employ transsynaptic signaling via essential secreted factors and cell surface receptors to promote each step of synaptic development. One such cell surface receptor, LRP4, has emerged as a synaptic organizer, playing a critical role in conveying extracellular signals to initiate diverse intracellular events during development. To date, LRP4 is largely known for its role in development of the mammalian neuromuscular junction, where it functions as a receptor for the synaptogenic signal Agrin to regulate synapse development. Recently however, LRP4 has emerged as a synapse organizer in the brain, where new functions for the protein continue to arise, adding further complexity to its already versatile roles. Additional findings indicate that LRP4 plays a role in disorders of the nervous system, including myasthenia gravis, amyotrophic lateral sclerosis, and Alzheimer's disease, demonstrating the need for further study to understand disease etiology. This review will highlight our current knowledge of how LRP4 functions in the nervous system, focusing on the diverse developmental roles and different modes this essential cell surface protein uses to ensure the formation of robust synaptic connections.
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Affiliation(s)
| | - Timothy J. Mosca
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA;
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Wang G, Sheng W, Tang J, Li X, Zhou J, Dong M. Cooperation of SRPK2, Numb and p53 in the malignant biology and chemosensitivity of colorectal cancer. Biosci Rep 2020; 40:BSR20191488. [PMID: 31898732 PMCID: PMC6970084 DOI: 10.1042/bsr20191488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 12/29/2019] [Accepted: 12/31/2019] [Indexed: 01/24/2023] Open
Abstract
Serine-arginine protein kinase 2 (SRPK2) is aberrantly expressed in human malignancies including colorectal cancer (CRC). However, little is known about the molecular mechanisms, and the role of SRPK2 in chemosensitivity remains unexplored in CRC. We recently showed that SRPK2 promotes pancreatic cancer progression by down-regulating Numb and p53. Therefore, we investigated the cooperation between SRPK2, Numb and p53 in the cell migration, invasion and chemosensitivity of CRC in vitro. Here, we showed that SRPK2 expression was higher in CRC tumors than in nontumor tissues. SRPK2 expression was positively associated with clinicopathological characteristics of CRC patients, including tumor differentiation, T stage, N stage and UICC stage. Additionally, SRPK2 had no association with mutant p53 (mtp53) in SW480 and SW620 cells, but negatively regulated Numb and wild-type p53 (wtp53) in response to 5-fluorouracil or cisplatin treatment in HCT116 cells. Moreover, SRPK2, Numb and p53 coimmunoprecipitated into a triple complex with or without the treatment of 5-fluorouracil in HCT116 cells, and p53 knockdown reversed the up-regulation of wtp53 induced by SRPK2 silencing with chemical agent treatment. Furthermore, overexpression of SRPK2 increased cell migration and invasion and decreased chemosensitivity to 5-fluorouracil or cisplatin in HCT116 cells. Conversely, SRPK2 silencing decreased cell migration and invasion and increased chemosensitivity to 5-fluorouracil or cisplatin, yet these effects could be reversed by p53 knockdown under chemical agent treatment. These results thus reveal a novel role of SRPK2-Numb-p53 signaling in the progression of CRC and demonstrate that SRPK2 is a potential therapeutic target for CRC clinical therapy.
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Affiliation(s)
- Guosen Wang
- Department of General Surgery, The First Affliated Hospital, Nanchang University, Nanchang 330006, Jiangxi, China
- Department of Gastrointestinal Surgery, The First Hospital, China Medical University, Shenyang 110001, Liaoning, China
| | - Weiwei Sheng
- Department of Gastrointestinal Surgery, The First Hospital, China Medical University, Shenyang 110001, Liaoning, China
| | - Jingtong Tang
- Department of Gastrointestinal Surgery, The First Hospital, China Medical University, Shenyang 110001, Liaoning, China
| | - Xin Li
- Department of Gastrointestinal Surgery, The First Hospital, China Medical University, Shenyang 110001, Liaoning, China
| | - Jianping Zhou
- Department of Gastrointestinal Surgery, The First Hospital, China Medical University, Shenyang 110001, Liaoning, China
| | - Ming Dong
- Department of Gastrointestinal Surgery, The First Hospital, China Medical University, Shenyang 110001, Liaoning, China
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Serine-Arginine Protein Kinase SRPK2 Modulates the Assembly of the Active Zone Scaffolding Protein CAST1/ERC2. Cells 2019; 8:cells8111333. [PMID: 31671734 PMCID: PMC6912806 DOI: 10.3390/cells8111333] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 10/08/2019] [Accepted: 10/11/2019] [Indexed: 01/10/2023] Open
Abstract
Neurons release neurotransmitters at a specialized region of the presynaptic membrane, the active zone (AZ), where a complex meshwork of proteins organizes the release apparatus. The formation of this proteinaceous cytomatrix at the AZ (CAZ) depends on precise homo- and hetero-oligomerizations of distinct CAZ proteins. The CAZ protein CAST1/ERC2 contains four coiled-coil (CC) domains that interact with other CAZ proteins, but also promote self-assembly, which is an essential step for its integration during AZ formation. The self-assembly and synaptic recruitment of the Drosophila protein Bruchpilot (BRP), a partial homolog of CAST1/ERC2, is modulated by the serine-arginine protein kinase (SRPK79D). Here, we demonstrate that overexpression of the vertebrate SRPK2 regulates the self-assembly of CAST1/ERC2 in HEK293T, SH-SY5Y and HT-22 cells and the CC1 and CC4 domains are involved in this process. Moreover, the isoform SRPK2 forms a complex with CAST1/ERC2 when co-expressed in HEK293T and SH-SY5Y cells. More importantly, SRPK2 is present in brain synaptic fractions and synapses, suggesting that this protein kinase might control the level of self-aggregation of CAST1/ERC2 in synapses, and thereby modulate presynaptic assembly.
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Driller JH, Lützkendorf J, Depner H, Siebert M, Kuropka B, Weise C, Piao C, Petzoldt AG, Lehmann M, Stelzl U, Zahedi R, Sickmann A, Freund C, Sigrist SJ, Wahl MC. Phosphorylation of the Bruchpilot N-terminus in Drosophila unlocks axonal transport of active zone building blocks. J Cell Sci 2019; 132:jcs.225151. [PMID: 30745339 DOI: 10.1242/jcs.225151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 01/24/2019] [Indexed: 01/31/2023] Open
Abstract
Protein scaffolds at presynaptic active zone membranes control information transfer at synapses. For scaffold biogenesis and maintenance, scaffold components must be safely transported along axons. A spectrum of kinases has been suggested to control transport of scaffold components, but direct kinase-substrate relationships and operational principles steering phosphorylation-dependent active zone protein transport are presently unknown. Here, we show that extensive phosphorylation of a 150-residue unstructured region at the N-terminus of the highly elongated Bruchpilot (BRP) active zone protein is crucial for ordered active zone precursor transport in Drosophila Point mutations that block SRPK79D kinase-mediated phosphorylation of the BRP N-terminus interfered with axonal transport, leading to BRP-positive axonal aggregates that also contain additional active zone scaffold proteins. Axonal aggregates formed only in the presence of non-phosphorylatable BRP isoforms containing the SRPK79D-targeted N-terminal stretch. We assume that specific active zone proteins are pre-assembled in transport packages and are thus co-transported as functional scaffold building blocks. Our results suggest that transient post-translational modification of a discrete unstructured domain of the master scaffold component BRP blocks oligomerization of these building blocks during their long-range transport.
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Affiliation(s)
- Jan H Driller
- Laboratory of Structural Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustraße 6, D-14195 Berlin, Germany
| | - Janine Lützkendorf
- Laboratory of Genetics, Institute of Biology, Freie Universität Berlin, Takustraße 6, D-14195 Berlin, Germany
| | - Harald Depner
- Laboratory of Genetics, Institute of Biology, Freie Universität Berlin, Takustraße 6, D-14195 Berlin, Germany
| | - Matthias Siebert
- Laboratory of Genetics, Institute of Biology, Freie Universität Berlin, Takustraße 6, D-14195 Berlin, Germany
| | - Benno Kuropka
- Laboratory of Protein Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, D-14195 Berlin, Germany
| | - Christoph Weise
- Laboratory of Protein Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, D-14195 Berlin, Germany
| | - Chengji Piao
- Laboratory of Genetics, Institute of Biology, Freie Universität Berlin, Takustraße 6, D-14195 Berlin, Germany
| | - Astrid G Petzoldt
- Laboratory of Genetics, Institute of Biology, Freie Universität Berlin, Takustraße 6, D-14195 Berlin, Germany.,NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Martin Lehmann
- Cellular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Roessle-Straße 10, D-13125 Berlin, Germany
| | - Ulrich Stelzl
- Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz, Universitätsplatz 1/I, A-8010 Graz, Austria
| | - René Zahedi
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Bunsen-Kirchhoff-Straße 11, D-44139 Dortmund, Germany
| | - Albert Sickmann
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Bunsen-Kirchhoff-Straße 11, D-44139 Dortmund, Germany
| | - Christian Freund
- Laboratory of Protein Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, D-14195 Berlin, Germany
| | - Stephan J Sigrist
- Laboratory of Genetics, Institute of Biology, Freie Universität Berlin, Takustraße 6, D-14195 Berlin, Germany .,NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Markus C Wahl
- Laboratory of Structural Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustraße 6, D-14195 Berlin, Germany .,Macromolecular Crystallography, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, D-12489 Berlin, Germany
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Wang ZH, Liu P, Liu X, Yu SP, Wang JZ, Ye K. Delta-secretase (AEP) mediates tau-splicing imbalance and accelerates cognitive decline in tauopathies. J Exp Med 2018; 215:3038-3056. [PMID: 30373880 PMCID: PMC6279401 DOI: 10.1084/jem.20180539] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 08/16/2018] [Accepted: 09/24/2018] [Indexed: 01/04/2023] Open
Abstract
Wang et al. demonstrate that AEP cleaves SRPK2 in tauopathies and plays a functional role in mediating tau-splicing imbalance and accelerating cognitive decline in mouse models of tauopathy. SRPK2 is abnormally activated in tauopathies including Alzheimer’s disease (AD). SRPK2 is known to play an important role in pre–mRNA splicing by phosphorylating SR-splicing factors. Dysregulation of tau exon 10 pre–mRNA splicing causes pathological imbalances in 3R- and 4R-tau, leading to neurodegeneration; however, the role of SRPK2 in these processes remains unclear. Here we show that delta-secretase (also known as asparagine endopeptidase; AEP), which is activated in AD, cleaves SRPK2 and increases its nuclear translocation as well as kinase activity, augmenting exon 10 inclusion. Conversely, AEP-uncleavable SRPK2 N342A mutant increases exon 10 exclusion. Lentiviral expression of truncated SRPK2 increases 4R-tau isoforms and accelerates cognitive decline in htau mice. Uncleavable SRPK2 N342A expression improves synaptic functions and prevents spatial memory deficits in tau intronic mutant FTDP-17 transgenic mice. Hence, AEP mediates tau-splicing imbalance in tauopathies via cleaving SRPK2.
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Affiliation(s)
- Zhi-Hao Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA
| | - Pai Liu
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA
| | - Xia Liu
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA
| | - Shan Ping Yu
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA
| | - Jian-Zhi Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China .,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Keqiang Ye
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA .,Tongji Hospital, Tongji University School of Medicine, Shanghai, China
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Wang ZH, Liu P, Liu X, Manfredsson FP, Sandoval IM, Yu SP, Wang JZ, Ye K. Delta-Secretase Phosphorylation by SRPK2 Enhances Its Enzymatic Activity, Provoking Pathogenesis in Alzheimer's Disease. Mol Cell 2017; 67:812-825.e5. [PMID: 28826672 DOI: 10.1016/j.molcel.2017.07.018] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 06/28/2017] [Accepted: 07/19/2017] [Indexed: 01/06/2023]
Abstract
Delta-secretase, a lysosomal asparagine endopeptidase (AEP), simultaneously cleaves both APP and tau, controlling the onset of pathogenesis of Alzheimer's disease (AD). However, how this protease is post-translationally regulated remains unclear. Here we report that serine-arginine protein kinase 2 (SRPK2) phosphorylates delta-secretase and enhances its enzymatic activity. SRPK2 phosphorylates serine 226 on delta-secretase and accelerates its autocatalytic cleavage, leading to its cytoplasmic translocation and escalated enzymatic activities. Delta-secretase is highly phosphorylated in human AD brains, tightly correlated with SRPK2 activity. Overexpression of a phosphorylation mimetic (S226D) in young 3xTg mice strongly promotes APP and tau fragmentation and facilitates amyloid plaque deposits and neurofibrillary tangle (NFT) formation, resulting in cognitive impairment. Conversely, viral injection of the non-phosphorylatable mutant (S226A) into 5XFAD mice decreases APP and tau proteolytic cleavage, attenuates AD pathologies, and reverses cognitive defects. Our findings support that delta-secretase phosphorylation by SRPK2 plays a critical role in aggravating AD pathogenesis.
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Affiliation(s)
- Zhi-Hao Wang
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Pai Liu
- Emory College of Arts and Sciences, Emory University, Atlanta, GA 30322, USA
| | - Xia Liu
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Fredric P Manfredsson
- Department of Translational Science and Molecular Medicine, Michigan State University, 333 Bostwick Avenue NE, Grand Rapids, MI 49503, USA
| | - Ivette M Sandoval
- Department of Translational Science and Molecular Medicine, Michigan State University, 333 Bostwick Avenue NE, Grand Rapids, MI 49503, USA
| | - Shan Ping Yu
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jian-Zhi Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Co-innovation Center of Neuroregeneration, Nantong 226001, China.
| | - Keqiang Ye
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA; Translational Center for Stem Cell Research, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China.
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Abstract
Copper is an essential element in many biological processes. The critical functions associated with copper have resulted from evolutionary harnessing of its potent redox activity. This same property also places copper in a unique role as a key modulator of cell signal transduction pathways. These pathways are the complex sequence of molecular interactions that drive all cellular mechanisms and are often associated with the interplay of key enzymes including kinases and phosphatases but also including intracellular changes in pools of smaller molecules. A growing body of evidence is beginning to delineate the how, when and where of copper-mediated control over cell signal transduction. This has been driven by research demonstrating critical changes to copper homeostasis in many disorders including cancer and neurodegeneration and therapeutic potential through control of disease-associated cell signalling changes by modulation of copper-protein interactions. This timely review brings together for the first time the diverse actions of copper as a key regulator of cell signalling pathways and discusses the potential strategies for controlling disease-associated signalling processes using copper modulators. It is hoped that this review will provide a valuable insight into copper as a key signal regulator and stimulate further research to promote our understanding of copper in disease and therapy.
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