1
|
Tian Y, Guan L, Qian Y, Wu Y, Gu Z. Effect of PPP1R14D gene high expression in lung adenocarcinoma knocked out on proliferation and apoptosis of DMS53 cell. Clin Transl Oncol 2022; 24:1914-1923. [PMID: 35579727 DOI: 10.1007/s12094-022-02842-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/13/2022] [Indexed: 12/24/2022]
Abstract
PURPOSE Globally, lung cancer remains the most commonly diagnosed cancer and the leading cause of cancer-related mortality. Lung adenocarcinoma (LUAD) is a common subtype of lung cancer and carries a poor prognosis. Treatment outcomes biomarkers in LUAD are critical, and there is currently a paucity of data; therefore, there is a need for novel biomarkers and newer therapeutic targets. METHODS Bayesian analysis was used to obtain the whole-genome t value of LUAD. Gene set enrichment analysis (GSEA) was conducted to obtain the normalized enrichment scores (NES) of the whole genome, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway was analyzed using the Gene Set Analysis Toolkit. Herein, we investigated the PPP1R14D expression level at the protein level in LUAD and the impact of PPP1R14D knockdown on the proliferation and apoptosis of LUAD cells in vitro. RESULTS A total of 483 LUAD samples and 59 normal control samples were included, and 904 differentially expressed genes (DEGs) and 504 LUAD-related genes reported in the literature were obtained. The DEGs showed that PPP1R14D was the most significantly up-regulated gene. Western blot of 30 cases of LUAD tissue and adjacent normal tissue also found that PPP1R14D was significantly highly expressed in cancer tissues. Lentivirus-mediated shRNA strategy effectively inhibited PPP1R14D expression in human LUAD cells DMS53, while PPP1R14D knockdown induced apoptosis and cell proliferation in DMS53 cells. CONCLUSION Abnormally up-regulated PPP1R14D promotes the survival and proliferation of tumor cells in human LUAD and may serve as a therapeutic and diagnostic target for LUAD.
Collapse
Affiliation(s)
- Ye Tian
- Ward 2, Department of Respiratory Medicine, The Second Affiliated Hospital of Qiqihar Medical University, Qiqihar, 161000, China
| | - Liguo Guan
- Department of Traditional Chinese Medicine, Jianhua District Hospital of Traditional Chinese Medicine, Qiqihar, 161000, China
| | - Yuting Qian
- Ward 2, Department of Respiratory Medicine, The Second Affiliated Hospital of Qiqihar Medical University, Qiqihar, 161000, China
| | - Yue Wu
- Ward 2, Department of Respiratory Medicine, The Second Affiliated Hospital of Qiqihar Medical University, Qiqihar, 161000, China
| | - Zexin Gu
- Ward 2, Department of Respiratory Medicine, The Second Affiliated Hospital of Qiqihar Medical University, Qiqihar, 161000, China.
| |
Collapse
|
2
|
Oslin K, Reho JJ, Lu Y, Khanal S, Kenchegowda D, Prior SJ, Fisher SA. Tissue-specific expression of myosin phosphatase subunits and isoforms in smooth muscle of mice and humans. Am J Physiol Regul Integr Comp Physiol 2022; 322:R281-R291. [PMID: 35107022 PMCID: PMC8917933 DOI: 10.1152/ajpregu.00196.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 01/24/2022] [Accepted: 01/24/2022] [Indexed: 11/22/2022]
Abstract
Alternative splicing of exon24 (E24) of myosin phosphatase targeting subunit 1 (Mypt1) by setting sensitivity to nitric oxide (NO)/cGMP-mediated relaxation is a key determinant of smooth muscle function. Here we defined expression of myosin phosphatase (MP) subunits and isoforms by creation of new genetic mouse models, assay of human and mouse tissues, and query of public databases. A Mypt1-LacZ reporter mouse revealed that Mypt1 transcription is turned on early in development during smooth muscle differentiation. Mypt1 is not as tightly restricted in its expression as smooth muscle myosin heavy chain (Myh11) and its E6 splice variant. Mypt1 is enriched in mature smooth versus nonmuscle cells. The E24 splice variant and leucine zipper minus protein isoform that it encodes is enriched in phasic versus tonic smooth muscle. In the vascular system, E24 splicing increases as vessel size decreases. In the gastrointestinal system, E24 splicing is most predominant in smooth muscle of the small intestine. Tissue-specific expression of MP subunits and Mypt1 E24 splicing is conserved in humans, whereas a splice variant of the inhibitory subunit (CPI-17) is unique to humans. A Mypt1 E24 mini-gene splicing reporter mouse generated to define patterns of E24 splicing in smooth muscle cells (SMCs) dispersed throughout the organ systems was unsuccessful. In summary, expression of Mypt1 and splicing of E24 is part of the program of smooth muscle differentiation, is further enhanced in phasic smooth muscle, and is conserved in humans. Its low-level expression in nonmuscle cells may confound its measurement in tissue samples.
Collapse
Affiliation(s)
- Kimberly Oslin
- University of Maryland-Baltimore Scholars Program, Baltimore, Maryland
| | - John J Reho
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Yuan Lu
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Sunita Khanal
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Doreswamy Kenchegowda
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Steven J Prior
- Baltimore Veterans Affairs Medical Center, Baltimore, Maryland
- Department of Kinesiology, University of Maryland School of Public Health, College Park, Maryland
- Baltimore Veterans Affairs Geriatric Research Education and Clinical Center, and Research and Development Service, Baltimore, Maryland
| | - Steven A Fisher
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
- Baltimore Veterans Affairs Medical Center, Baltimore, Maryland
| |
Collapse
|
3
|
Ghasemi Z, Naderi N, Shojaei A, Raoufy MR, Ahmadirad N, Barkley V, Mirnajafi-Zadeh J. Group I metabotropic glutamate receptors contribute to the antiepileptic effect of electrical stimulation in hippocampal CA1 pyramidal neurons. Epilepsy Res 2021; 178:106821. [PMID: 34839145 DOI: 10.1016/j.eplepsyres.2021.106821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 11/04/2021] [Accepted: 11/16/2021] [Indexed: 11/17/2022]
Abstract
Low-frequency deep brain stimulation (LFS) inhibits neuronal hyperexcitability during epilepsy. Accordingly, the use of LFS as a treatment method for patients with drug-resistant epilepsy has been proposed. However, the LFS antiepileptic mechanisms are not fully understood. Here, the role of metabotropic glutamate receptors group I (mGluR I) in LFS inhibitory action on epileptiform activity (EA) was investigated. EA was induced by increasing the K+ concentration in artificial cerebrospinal fluid (ACSF) up to 12 mM in hippocampal slices of male Wistar rats. LFS (1 Hz, 900 pulses) was delivered to the bundles of Schaffer collaterals at the beginning of EA. The excitability of CA1 pyramidal neurons was assayed by intracellular whole-cell recording. Applying LFS reduced the firing frequency during EA and substantially moved the membrane potential toward repolarization after a high-K+ ACSF washout. In addition, LFS attenuated the EA-generated neuronal hyperexcitability. A blockade of both mGluR 1 and mGluR 5 prevented the inhibitory action of LFS on EA-generated neuronal hyperexcitability. Activation of mGluR I mimicked the LFS effects and had similar inhibitory action on excitability of CA1 pyramidal neurons following EA. However, mGluR I agonist's antiepileptic action was not as strong as LFS. The observed LFS effects were significantly attenuated in the presence of a PKC inhibitor. Altogether, the LFS' inhibitory action on neuronal hyperexcitability following EA relies, in part, on the activity of mGluR I and a PKC-related signaling pathway.
Collapse
Affiliation(s)
- Zahra Ghasemi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - Nima Naderi
- Department of Pharmacology and Toxicology, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Shojaei
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mohammad Reza Raoufy
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Nooshin Ahmadirad
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Victoria Barkley
- Krembil Research Institute, University Health Network, Toronto, Canada
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Institute for Brain Sciences and Cognition, Tarbiat Modares University, Tehran, Iran.
| |
Collapse
|
4
|
Reyes-García SE, Escobar ML. Calcineurin Participation in Hebbian and Homeostatic Plasticity Associated With Extinction. Front Cell Neurosci 2021; 15:685838. [PMID: 34220454 PMCID: PMC8242195 DOI: 10.3389/fncel.2021.685838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/25/2021] [Indexed: 12/21/2022] Open
Abstract
In nature, animals need to adapt to constant changes in their environment. Learning and memory are cognitive capabilities that allow this to happen. Extinction, the reduction of a certain behavior or learning previously established, refers to a very particular and interesting type of learning that has been the basis of a series of therapies to diminish non-adaptive behaviors. In recent years, the exploration of the cellular and molecular mechanisms underlying this type of learning has received increasing attention. Hebbian plasticity (the activity-dependent modification of the strength or efficacy of synaptic transmission), and homeostatic plasticity (the homeostatic regulation of plasticity) constitute processes intimately associated with memory formation and maintenance. Particularly, long-term depression (LTD) has been proposed as the underlying mechanism of extinction, while the protein phosphatase calcineurin (CaN) has been widely related to both the extinction process and LTD. In this review, we focus on the available evidence that sustains CaN modulation of LTD and its association with extinction. Beyond the classic view, we also examine the interconnection among extinction, Hebbian and homeostatic plasticity, as well as emergent evidence of the participation of kinases and long-term potentiation (LTP) on extinction learning, highlighting the importance of the balance between kinases and phosphatases in the expression of extinction. Finally, we also integrate data that shows the association between extinction and less-studied phenomena, such as synaptic silencing and engram formation that open new perspectives in the field.
Collapse
Affiliation(s)
- Salma E Reyes-García
- Laboratorio de Neurobiología del Aprendizaje y la Memoria, División de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Martha L Escobar
- Laboratorio de Neurobiología del Aprendizaje y la Memoria, División de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| |
Collapse
|
5
|
Lang I, Virk G, Zheng DC, Young J, Nguyen MJ, Amiri R, Fong M, Arata A, Chadaideh KS, Walsh S, Weiser DC. The Evolution of Duplicated Genes of the Cpi-17/Phi-1 ( ppp1r14) Family of Protein Phosphatase 1 Inhibitors in Teleosts. Int J Mol Sci 2020; 21:ijms21165709. [PMID: 32784920 PMCID: PMC7460850 DOI: 10.3390/ijms21165709] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 08/07/2020] [Indexed: 11/29/2022] Open
Abstract
The Cpi-17 (ppp1r14) gene family is an evolutionarily conserved, vertebrate specific group of protein phosphatase 1 (PP1) inhibitors. When phosphorylated, Cpi-17 is a potent inhibitor of myosin phosphatase (MP), a holoenzyme complex of the regulatory subunit Mypt1 and the catalytic subunit PP1. Myosin phosphatase dephosphorylates the regulatory myosin light chain (Mlc2) and promotes actomyosin relaxation, which in turn, regulates numerous cellular processes including smooth muscle contraction, cytokinesis, cell motility, and tumor cell invasion. We analyzed zebrafish homologs of the Cpi-17 family, to better understand the mechanisms of myosin phosphatase regulation. We found single homologs of both Kepi (ppp1r14c) and Gbpi (ppp1r14d) in silico, but we detected no expression of these genes during early embryonic development. Cpi-17 (ppp1r14a) and Phi-1 (ppp1r14b) each had two duplicate paralogs, (ppp1r14aa and ppp1r14ab) and (ppp1r14ba and ppp1r14bb), which were each expressed during early development. The spatial expression pattern of these genes has diverged, with ppp1r14aa and ppp1r14bb expressed primarily in smooth muscle and skeletal muscle, respectively, while ppp1r14ab and ppp1r14ba are primarily expressed in neural tissue. We observed that, in in vitro and heterologous cellular systems, the Cpi-17 paralogs both acted as potent myosin phosphatase inhibitors, and were indistinguishable from one another. In contrast, the two Phi-1 paralogs displayed weak myosin phosphatase inhibitory activity in vitro, and did not alter myosin phosphorylation in cells. Through deletion and chimeric analysis, we identified that the difference in specificity for myosin phosphatase between Cpi-17 and Phi-1 was encoded by the highly conserved PHIN (phosphatase holoenzyme inhibitory) domain, and not the more divergent N- and C- termini. We also showed that either Cpi-17 paralog can rescue the knockdown phenotype, but neither Phi-1 paralog could do so. Thus, we provide new evidence about the biochemical and developmental distinctions of the zebrafish Cpi-17 protein family.
Collapse
Affiliation(s)
- Irene Lang
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Guneet Virk
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Dale C. Zheng
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Jason Young
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Michael J. Nguyen
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Rojin Amiri
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Michelle Fong
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Alisa Arata
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Katia S. Chadaideh
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Susan Walsh
- Life Sciences, Soka University of America, Aliso Viejo, CA 92656, USA;
| | - Douglas C. Weiser
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
- Correspondence: ; Tel.: +1-209-946-2955
| |
Collapse
|
6
|
Annunziata MC, Parisi M, Esposito G, Fabbrocini G, Ammendola R, Cattaneo F. Phosphorylation Sites in Protein Kinases and Phosphatases Regulated by Formyl Peptide Receptor 2 Signaling. Int J Mol Sci 2020; 21:ijms21113818. [PMID: 32471307 PMCID: PMC7312799 DOI: 10.3390/ijms21113818] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 05/22/2020] [Accepted: 05/25/2020] [Indexed: 12/19/2022] Open
Abstract
FPR1, FPR2, and FPR3 are members of Formyl Peptides Receptors (FPRs) family belonging to the GPCR superfamily. FPR2 is a low affinity receptor for formyl peptides and it is considered the most promiscuous member of this family. Intracellular signaling cascades triggered by FPRs include the activation of different protein kinases and phosphatase, as well as tyrosine kinase receptors transactivation. Protein kinases and phosphatases act coordinately and any impairment of their activation or regulation represents one of the most common causes of several human diseases. Several phospho-sites has been identified in protein kinases and phosphatases, whose role may be to expand the repertoire of molecular mechanisms of regulation or may be necessary for fine-tuning of switch properties. We previously performed a phospho-proteomic analysis in FPR2-stimulated cells that revealed, among other things, not yet identified phospho-sites on six protein kinases and one protein phosphatase. Herein, we discuss on the selective phosphorylation of Serine/Threonine-protein kinase N2, Serine/Threonine-protein kinase PRP4 homolog, Serine/Threonine-protein kinase MARK2, Serine/Threonine-protein kinase PAK4, Serine/Threonine-protein kinase 10, Dual specificity mitogen-activated protein kinase kinase 2, and Protein phosphatase 1 regulatory subunit 14A, triggered by FPR2 stimulation. We also describe the putative FPR2-dependent signaling cascades upstream to these specific phospho-sites.
Collapse
Affiliation(s)
- Maria Carmela Annunziata
- Department of Clinical Medicine and Surgery, School of Medicine, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy; (M.C.A.); (M.P.); (G.F.)
| | - Melania Parisi
- Department of Clinical Medicine and Surgery, School of Medicine, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy; (M.C.A.); (M.P.); (G.F.)
| | - Gabriella Esposito
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy; (G.E.); (R.A.)
| | - Gabriella Fabbrocini
- Department of Clinical Medicine and Surgery, School of Medicine, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy; (M.C.A.); (M.P.); (G.F.)
| | - Rosario Ammendola
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy; (G.E.); (R.A.)
| | - Fabio Cattaneo
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy; (G.E.); (R.A.)
- Correspondence: ; Fax: +39-081-7464-359
| |
Collapse
|
7
|
A Late Phase of Long-Term Synaptic Depression in Cerebellar Purkinje Cells Requires Activation of MEF2. Cell Rep 2020; 26:1089-1097.e3. [PMID: 30699340 PMCID: PMC6433166 DOI: 10.1016/j.celrep.2019.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 09/06/2018] [Accepted: 12/28/2018] [Indexed: 12/18/2022] Open
Abstract
The MEF2 family of transcription factors restricts excitatory synapse number in an activity-dependent fashion during development, yet MEF2 has not been implicated in long-term synaptic depression (LTD), which is thought to initiate synapse elimination. Mutations in MEF2 pathways are implicated in autism spectrum disorders, which include cerebellar dysfunction. Here, we test the hypothesis that cerebellar LTD requires postsynaptic activation of MEF2. Knockdown of MEF2D produces suppression of the transcription-dependent late phase of LTD in cultured Purkinje cells. The late phase of LTD is also completely blocked in Purkinje cells derived from MEF2A+MEF2D null mice and rescued with plasmids that drive expression of MEF2D but not phosphatase-resistant mutant MEF2D S444D. Wild-type Purkinje cells transfected with a constitutively active form of MEF2 show no alterations of synaptic strength. Thus, postsynaptic activation of MEF2 by S444 dephosphorylation is necessary, but not sufficient, for the late phase of cerebellar LTD. Neurodevelopmental disorders can reflect defects in synaptic pruning, which is thought to require activity-dependent weakening of synapses, a process called long-term depression. Andzelm et al. show that MEF2, which is important for neuronal development, is required for the late phase of long-term depression in the cerebellum.
Collapse
|
8
|
Mejias R, Chiu SL, Han M, Rose R, Gil-Infante A, Zhao Y, Huganir RL, Wang T. Purkinje cell-specific Grip1/2 knockout mice show increased repetitive self-grooming and enhanced mGluR5 signaling in cerebellum. Neurobiol Dis 2019; 132:104602. [PMID: 31476380 DOI: 10.1016/j.nbd.2019.104602] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/30/2019] [Accepted: 08/30/2019] [Indexed: 01/16/2023] Open
Abstract
Cerebellar Purkinje cell (PC) loss is a consistent pathological finding in autism. However, neural mechanisms of PC-dysfunction in autism remain poorly characterized. Glutamate receptor interacting proteins 1/2 (Grip1/2) regulate AMPA receptor (AMPAR) trafficking and synaptic strength. To evaluate role of PC-AMPAR signaling in autism, we produced PC-specific Grip1/2 knockout mice by crossing Grip2 conventional and Grip1 conditional KO with L7-Cre driver mice. PCs in the mutant mice showed normal morphology and number, and a lack of Grip1/2 expression. Rodent behavioral testing identified normal ambulation, anxiety, social interaction, and an increase in repetitive self-grooming. Electrophysiology studies revealed normal mEPSCs but an impaired mGluR-LTD at the Parallel Fiber-PC synapses. Immunoblots showed increased expression of mGluR5 and Arc, and enhanced phosphorylation of P38 and AKT in cerebellum of PC-specific Grip1/2 knockout mice. Results indicate that loss of Grip1/2 in PCs contributes to increased repetitive self-grooming, a core autism behavior in mice. Results support a role of AMPAR trafficking defects in PCs and disturbances of mGluR5 signaling in cerebellum in the pathogenesis of repetitive behaviors.
Collapse
Affiliation(s)
- Rebeca Mejias
- McKusick-Nathans Department of Genetic Medicine and Department of Pediatrics, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Physiology, University of Seville, 41012 Seville, Spain.
| | - Shu-Ling Chiu
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Mei Han
- McKusick-Nathans Department of Genetic Medicine and Department of Pediatrics, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Rebecca Rose
- McKusick-Nathans Department of Genetic Medicine and Department of Pediatrics, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Ana Gil-Infante
- Department of Physiology, University of Seville, 41012 Seville, Spain
| | - Yifan Zhao
- McKusick-Nathans Department of Genetic Medicine and Department of Pediatrics, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Richard L Huganir
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Tao Wang
- McKusick-Nathans Department of Genetic Medicine and Department of Pediatrics, Johns Hopkins University, Baltimore, MD 21205, USA.
| |
Collapse
|
9
|
Zhang XF, Ajeti V, Tsai N, Fereydooni A, Burns W, Murrell M, De La Cruz EM, Forscher P. Regulation of axon growth by myosin II-dependent mechanocatalysis of cofilin activity. J Cell Biol 2019; 218:2329-2349. [PMID: 31123185 PMCID: PMC6605792 DOI: 10.1083/jcb.201810054] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 03/26/2019] [Accepted: 05/06/2019] [Indexed: 12/24/2022] Open
Abstract
Synergism between myosin II contractility and cofilin activity modulates serotonin-dependent axon growth. Normally, cofilin-dependent decreases in actin density are compensated by increases in point contact density and traction force; however, myosin hyperactivation leads to catastrophic decreases in actin network density and neurite retraction. Serotonin (5-HT) is known to increase the rate of growth cone advance via cofilin-dependent increases in retrograde actin network flow and nonmuscle myosin II activity. We report that myosin II activity is regulated by PKC during 5-HT responses and that PKC activity is necessary for increases in traction force normally associated with these growth responses. 5-HT simultaneously induces cofilin-dependent decreases in actin network density and PKC-dependent increases in point contact density. These reciprocal effects facilitate increases in traction force production in domains exhibiting decreased actin network density. Interestingly, when PKC activity was up-regulated, 5-HT treatments resulted in myosin II hyperactivation accompanied by catastrophic cofilin-dependent decreases in actin filament density, sudden decreases in traction force, and neurite retraction. These results reveal a synergistic relationship between cofilin and myosin II that is spatiotemporally regulated in the growth cone via mechanocatalytic effects to modulate neurite growth.
Collapse
Affiliation(s)
- Xiao-Feng Zhang
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT
| | - Visar Ajeti
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT.,Department of Biomedical Engineering, University of Connecticut Health Center, Farmington, CT
| | - Nicole Tsai
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT.,Department of Ophthalmology, University of California, San Francisco, California, CA
| | - Arash Fereydooni
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT
| | - William Burns
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT
| | - Michael Murrell
- Department of Biomedical Engineering, Yale University, New Haven, CT
| | - Enrique M De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - Paul Forscher
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT
| |
Collapse
|
10
|
Zhou Y, Qiu L, Sterpka A, Wang H, Chu F, Chen X. Comparative Phosphoproteomic Profiling of Type III Adenylyl Cyclase Knockout and Control, Male, and Female Mice. Front Cell Neurosci 2019; 13:34. [PMID: 30814930 PMCID: PMC6381875 DOI: 10.3389/fncel.2019.00034] [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: 10/30/2018] [Accepted: 01/23/2019] [Indexed: 11/26/2022] Open
Abstract
Type III adenylyl cyclase (AC3, ADCY3) is predominantly enriched in neuronal primary cilia throughout the central nervous system (CNS). Genome-wide association studies in humans have associated ADCY3 with major depressive disorder and autistic spectrum disorder, both of which exhibit sexual dimorphism. To date, it is unclear how AC3 affects protein phosphorylation and signal networks in central neurons, and what causes the sexual dimorphism of autism. We employed a mass spectrometry (MS)-based phosphoproteomic approach to quantitatively profile differences in phosphorylation between inducible AC3 knockout (KO) and wild type (WT), male and female mice. In total, we identified 4,655 phosphopeptides from 1,756 proteins, among which 565 phosphopeptides from 322 proteins were repetitively detected in all samples. Over 46% phosphopeptides were identified in at least three out of eight biological replicas. Comparison of AC3 KO and WT datasets revealed that phosphopeptides with motifs matching proline-directed kinases' recognition sites had a lower abundance in the KO dataset than in WTs. We detected 14 phosphopeptides restricted to WT dataset (i.e., Rabl6, Spast and Ppp1r14a) and 35 exclusively in KOs (i.e., Sptan1, Arhgap20, Arhgap44, and Pde1b). Moreover, 95 phosphopeptides (out of 90 proteins) were identified only in female dataset and 26 only in males. Label-free MS spectrum quantification using Skyline further identified phosphopeptides that had higher abundance in each sample group. In total, 204 proteins had sex-biased phosphorylation and 167 of them had increased expression in females relative to males. Interestingly, among the 204 gender-biased phosphoproteins, 31% were found to be associated with autism, including Dlg1, Dlgap2, Syn1, Syngap1, Ctnna1, Ctnnd1, Ctnnd2, Pkp4, and Arvcf. Therefore, this study also provides the first phosphoproteomics evidence suggesting that gender-biased post-translational phosphorylation may be implicated in the sexual dimorphism of autism.
Collapse
Affiliation(s)
- Yuxin Zhou
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, United States
| | - Liyan Qiu
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, United States
| | - Ashley Sterpka
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, United States
| | - Haiying Wang
- Department of Statistics, University of Connecticut, Storrs, CT, United States
| | - Feixia Chu
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, United States
| | - Xuanmao Chen
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, United States
| |
Collapse
|
11
|
Yang Q, Fujii W, Kaji N, Kakuta S, Kada K, Kuwahara M, Tsubone H, Ozaki H, Hori M. The essential role of phospho‐T38 CPI‐17 in the maintenance of physiological blood pressure using genetically modified mice. FASEB J 2018; 32:2095-2109. [DOI: 10.1096/fj.201700794r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Affiliation(s)
- Qunhui Yang
- Department of Veterinary Pharmacology, Laboratory of Applied Genetics, Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Wataru Fujii
- Laboratory of Applied Genetics, Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Noriyuki Kaji
- Department of Veterinary Pharmacology, Laboratory of Applied Genetics, Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Shigeru Kakuta
- Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Kodai Kada
- Department of Veterinary Pharmacology, Laboratory of Applied Genetics, Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Masayoshi Kuwahara
- Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Hirokazu Tsubone
- Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Hiroshi Ozaki
- Department of Veterinary Pharmacology, Laboratory of Applied Genetics, Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Masatoshi Hori
- Department of Veterinary Pharmacology, Laboratory of Applied Genetics, Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| |
Collapse
|
12
|
Eto M, Kitazawa T. Diversity and plasticity in signaling pathways that regulate smooth muscle responsiveness: Paradigms and paradoxes for the myosin phosphatase, the master regulator of smooth muscle contraction. J Smooth Muscle Res 2018; 53:1-19. [PMID: 28260704 PMCID: PMC5364378 DOI: 10.1540/jsmr.53.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
A hallmark of smooth muscle cells is their ability to adapt their functions to meet temporal and chronic fluctuations in their demands. These functions include force development and growth. Understanding the mechanisms underlying the functional plasticity of smooth muscles, the major constituent of organ walls, is fundamental to elucidating pathophysiological rationales of failures of organ functions. Also, the knowledge is expected to facilitate devising innovative strategies that more precisely monitor and normalize organ functions by targeting individual smooth muscles. Evidence has established a current paradigm that the myosin light chain phosphatase (MLCP) is a master regulator of smooth muscle responsiveness to stimuli. Cellular MLCP activity is negatively and positively regulated in response to G-protein activation and cAMP/cGMP production, respectively, through the MYPT1 regulatory subunit and an endogenous inhibitor protein named CPI-17. In this article we review the outcomes from two decade of research on the CPI-17 signaling and discuss emerging paradoxes in the view of signaling pathways regulating smooth muscle functions through MLCP.
Collapse
Affiliation(s)
- Masumi Eto
- Department of Molecular Physiology and Biophysics, Sidney Kimmel Medical College at Thomas Jefferson University and Sidney Kimmel Cancer Center, 1020 Locust Street, Philadelphia, PA19107, USA
| | | |
Collapse
|
13
|
Hagel C, Dornblut C, Schulz A, Wiehl U, Friedrich RE, Huckhagel T, Mautner VF, Morrison H. The putative oncogene CPI-17 is up-regulated in schwannoma. Neuropathol Appl Neurobiol 2018; 42:664-668. [PMID: 27248983 DOI: 10.1111/nan.12330] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 04/19/2016] [Accepted: 06/01/2016] [Indexed: 12/25/2022]
Affiliation(s)
- C Hagel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - C Dornblut
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - A Schulz
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - U Wiehl
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - R E Friedrich
- Department of Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - T Huckhagel
- Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - V-F Mautner
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - H Morrison
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| |
Collapse
|
14
|
Filter JJ, Williams BC, Eto M, Shalloway D, Goldberg ML. Unfair competition governs the interaction of pCPI-17 with myosin phosphatase (PP1-MYPT1). eLife 2017; 6. [PMID: 28387646 PMCID: PMC5441869 DOI: 10.7554/elife.24665] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Accepted: 03/31/2017] [Indexed: 11/30/2022] Open
Abstract
The small phosphoprotein pCPI-17 inhibits myosin light-chain phosphatase (MLCP). Current models postulate that during muscle relaxation, phosphatases other than MLCP dephosphorylate and inactivate pCPI-17 to restore MLCP activity. We show here that such hypotheses are insufficient to account for the observed rapidity of pCPI-17 inactivation in mammalian smooth muscles. Instead, MLCP itself is the critical enzyme for pCPI-17 dephosphorylation. We call the mutual sequestration mechanism through which pCPI-17 and MLCP interact inhibition by unfair competition: MLCP protects pCPI-17 from other phosphatases, while pCPI-17 blocks other substrates from MLCP’s active site. MLCP dephosphorylates pCPI-17 at a slow rate that is, nonetheless, both sufficient and necessary to explain the speed of pCPI-17 dephosphorylation and the consequent MLCP activation during muscle relaxation. DOI:http://dx.doi.org/10.7554/eLife.24665.001
Collapse
Affiliation(s)
- Joshua J Filter
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Byron C Williams
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Masumi Eto
- Department of Molecular Physiology and Biophysics, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, United States
| | - David Shalloway
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Michael L Goldberg
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| |
Collapse
|
15
|
Stochastic Induction of Long-Term Potentiation and Long-Term Depression. Sci Rep 2016; 6:30899. [PMID: 27485552 PMCID: PMC4971485 DOI: 10.1038/srep30899] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/10/2016] [Indexed: 01/23/2023] Open
Abstract
Long-term depression (LTD) and long-term potentiation (LTP) of granule-Purkinje cell synapses are persistent synaptic alterations induced by high and low rises of the intracellular calcium ion concentration ([Ca2+]), respectively. The occurrence of LTD involves the activation of a positive feedback loop formed by protein kinase C, phospholipase A2, and the extracellular signal-regulated protein kinase pathway, and its expression comprises the reduction of the population of synaptic AMPA receptors. Recently, a stochastic computational model of these signalling processes demonstrated that, in single synapses, LTD is probabilistic and bistable. Here, we expanded this model to simulate LTP, which requires protein phosphatases and the increase in the population of synaptic AMPA receptors. Our results indicated that, in single synapses, while LTD is bistable, LTP is gradual. Ca2+ induced both processes stochastically. The magnitudes of the Ca2+ signals and the states of the signalling network regulated the likelihood of LTP and LTD and defined dynamic macroscopic Ca2+ thresholds for the synaptic modifications in populations of synapses according to an inverse Bienenstock, Cooper and Munro (BCM) rule or a sigmoidal function. In conclusion, our model presents a unifying mechanism that explains the macroscopic properties of LTP and LTD from their dynamics in single synapses.
Collapse
|
16
|
Optimization of cerebellar purkinje neuron cultures and development of a plasmid-based method for purkinje neuron-specific, miRNA-mediated protein knockdown. Methods Cell Biol 2015; 131:177-97. [PMID: 26794514 DOI: 10.1016/bs.mcb.2015.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We present a simple and efficient method to knock down proteins specifically in Purkinje neurons (PN) present in mixed mouse primary cerebellar cultures. This method utilizes the introduction via nucleofection of a plasmid encoding a specific miRNA downstream of the L7/Pcp2 promoter, which drives PN-specific expression. As proof-of-principle, we used this plasmid to knock down the motor protein myosin Va, which is required for the targeting of smooth endoplasmic reticulum (ER) into PN spines. Consistent with effective knockdown, transfected PNs robustly phenocopied PNs from dilute-lethal (myosin Va-null) mice with regard to the ER targeting defect. Importantly, our plasmid-based approach is less challenging technically and more specific to PNs than several alternative methods (e.g., biolistic- and lentiviral-based introduction of siRNAs). We also present a number of improvements for generating mixed cerebellar cultures that shorten the procedure and improve the total yield of PNs, and of transfected PNs, considerably. Finally, we present a method to rescue cerebellar cultures that develop large cell aggregates, a common problem that otherwise precludes the further use of the culture.
Collapse
|
17
|
Grasselli G, Hansel C. Cerebellar long-term potentiation: cellular mechanisms and role in learning. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 117:39-51. [PMID: 25172628 DOI: 10.1016/b978-0-12-420247-4.00003-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Activity-dependent long-term plasticity of synaptic transmission, such as in long-term potentiation (LTP) and long-term depression (LTD), provides a cellular correlate of experience-driven learning. While at excitatory synapses in the hippocampus and neocortex LTP is seen as the primary learning mechanism, it has been widely assumed that cerebellar motor learning is mediated by LTD at parallel fiber (PF)-Purkinje cell synapses instead. However, recent work on mouse mutants with deficits in AMPA receptor internalization has demonstrated that motor learning can occur in the absence of LTD, suggesting that LTD is not essential. Another recent study has shifted attention toward LTP at PF synapses, showing that blockade of LTP severely affects motor learning. Here, we review the cellular and molecular events that are involved in LTP induction and discuss whether LTP might indeed play a more significant role in cerebellar learning than previously anticipated.
Collapse
Affiliation(s)
- Giorgio Grasselli
- Department of Neurobiology, University of Chicago, Chicago, Illinois, USA
| | - Christian Hansel
- Department of Neurobiology, University of Chicago, Chicago, Illinois, USA.
| |
Collapse
|
18
|
Chang WP, Lu HC, Shyu BC. Treatment with direct-current stimulation against cingulate seizure-like activity induced by 4-aminopyridine and bicuculline in an in vitro mouse model. Exp Neurol 2015; 265:180-92. [DOI: 10.1016/j.expneurol.2015.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 01/13/2015] [Accepted: 02/05/2015] [Indexed: 01/03/2023]
|
19
|
MAG-EPA and 17,18-EpETE target cytoplasmic signalling pathways to reduce short-term airway hyperresponsiveness. Pflugers Arch 2014; 467:1591-1605. [DOI: 10.1007/s00424-014-1584-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 07/16/2014] [Accepted: 07/18/2014] [Indexed: 12/30/2022]
|
20
|
Puig-Butillé JA, Malvehy J, Potrony M, Trullas C, Garcia-García F, Dopazo J, Puig S. Role of CPI-17 in restoring skin homoeostasis in cutaneous field of cancerization: effects of topical application of a film-forming medical device containing photolyase and UV filters. Exp Dermatol 2014; 22:494-6. [PMID: 23800065 PMCID: PMC3748792 DOI: 10.1111/exd.12177] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2013] [Indexed: 12/19/2022]
Abstract
Cutaneous field of cancerization (CFC) is caused in part by the carcinogenic effect of the cyclobutane pyrimidine dimers CPD and 6-4 photoproducts (6-4PPs). Photoreactivation is carried out by photolyases which specifically recognize and repair both photoproducts. The study evaluates the molecular effects of topical application of a film-forming medical device containing photolyase and UV filters on the precancerous field in AK from seven patients. Skin improvement after treatment was confirmed in all patients by histopathological and molecular assessment. A gene set analysis showed that skin recovery was associated with biological processes involved in tissue homoeostasis and cell maintenance. The CFC response was associated with over-expression of the CPI-17 gene, and a dependence on the initial expression level was observed (P = 0.001). Low CPI-17 levels were directly associated with pro-inflammatory genes such as TNF (P = 0.012) and IL-1B (P = 0.07). Our results suggest a role for CPI-17 in restoring skin homoeostasis in CFC lesions.
Collapse
Affiliation(s)
- Joan Anton Puig-Butillé
- Melanoma Unit, Biochemistry and Molecular Genetics Service, Hospital Clinic of Barcelona, IDIBAPS, Barcelona, Spain; CIBER de Enfermedades Raras, Instituto de Salud Carlos III, Barcelona, Spain
| | | | | | | | | | | | | |
Collapse
|
21
|
Korrodi-Gregório L, Abrantes J, Muller T, Melo-Ferreira J, Marcus K, da Cruz e Silva OAB, Fardilha M, Esteves PJ. Not so pseudo: the evolutionary history of protein phosphatase 1 regulatory subunit 2 and related pseudogenes. BMC Evol Biol 2013; 13:242. [PMID: 24195737 PMCID: PMC3840573 DOI: 10.1186/1471-2148-13-242] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 10/29/2013] [Indexed: 01/23/2023] Open
Abstract
Background Pseudogenes are traditionally considered “dead” genes, therefore lacking biological functions. This view has however been challenged during the last decade. This is the case of the Protein phosphatase 1 regulatory subunit 2 (PPP1R2) or inhibitor-2 gene family, for which several incomplete copies exist scattered throughout the genome. Results In this study, the pseudogenization process of PPP1R2 was analyzed. Ten PPP1R2-related pseudogenes (PPP1R2P1-P10), highly similar to PPP1R2, were retrieved from the human genome assembly present in the databases. The phylogenetic analysis of mammalian PPP1R2 and related pseudogenes suggested that PPP1R2P7 and PPP1R2P9 retroposons appeared before the great mammalian radiation, while the remaining pseudogenes are primate-specific and retroposed at different times during Primate evolution. Although considered inactive, four of these pseudogenes seem to be transcribed and possibly possess biological functions. Given the role of PPP1R2 in sperm motility, the presence of these proteins was assessed in human sperm, and two PPP1R2-related proteins were detected, PPP1R2P3 and PPP1R2P9. Signatures of negative and positive selection were also detected in PPP1R2P9, further suggesting a role as a functional protein. Conclusions The results show that contrary to initial observations PPP1R2-related pseudogenes are not simple bystanders of the evolutionary process but may rather be at the origin of genes with novel functions.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Pedro J Esteves
- CIBIO-UP, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, InBIO, Laboratório Associado, Campus Agrário de Vairão, Vairão, Portugal.
| |
Collapse
|
22
|
Yang Q, Zhang XF, Van Goor D, Dunn AP, Hyland C, Medeiros N, Forscher P. Protein kinase C activation decreases peripheral actin network density and increases central nonmuscle myosin II contractility in neuronal growth cones. Mol Biol Cell 2013; 24:3097-114. [PMID: 23966465 PMCID: PMC3784383 DOI: 10.1091/mbc.e13-05-0289] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
PKC activation enhances myosin II contractility in the central growth cone domain while decreasing actin density and increasing actin network flow rates in the peripheral domain. This dual mode of action has mechanistic implications for interpreting reported effects of PKC on growth cone guidance and neuronal regeneration. Protein kinase C (PKC) can dramatically alter cell structure and motility via effects on actin filament networks. In neurons, PKC activation has been implicated in repulsive guidance responses and inhibition of axon regeneration; however, the cytoskeletal mechanisms underlying these effects are not well understood. Here we investigate the acute effects of PKC activation on actin network structure and dynamics in large Aplysia neuronal growth cones. We provide evidence of a novel two-tiered mechanism of PKC action: 1) PKC activity enhances myosin II regulatory light chain phosphorylation and C-kinase–potentiated protein phosphatase inhibitor phosphorylation. These effects are correlated with increased contractility in the central cytoplasmic domain. 2) PKC activation results in significant reduction of P-domain actin network density accompanied by Arp2/3 complex delocalization from the leading edge and increased rates of retrograde actin network flow. Our results show that PKC activation strongly affects both actin polymerization and myosin II contractility. This synergistic mode of action is relevant to understanding the pleiotropic reported effects of PKC on neuronal growth and regeneration.
Collapse
Affiliation(s)
- Qing Yang
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511
| | | | | | | | | | | | | |
Collapse
|
23
|
Kim KM, Adyshev DM, Kása A, Zemskov EA, Kolosova IA, Csortos C, Verin AD. Putative protein partners for the human CPI-17 protein revealed by bacterial two-hybrid screening. Microvasc Res 2013; 88:19-24. [PMID: 23583905 DOI: 10.1016/j.mvr.2013.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 02/26/2013] [Accepted: 04/01/2013] [Indexed: 01/06/2023]
Abstract
We have previously demonstrated that PKC-potentiated inhibitory protein of protein phosphatase-1 (CPI-17) is expressed in lung endothelium. CPI-17, a specific inhibitor of myosin light chain phosphatase (MLCP), is involved in the endothelial cytoskeletal and barrier regulation. In this paper, we report the identification of fourteen putative CPI-17 interacting proteins in the lung using BacterioMatch Two-Hybrid System. Five of them: plectin 1 isoform 1, alpha II spectrin, OK/SW-CL.16, gelsolin isoform a, and junction plakoglobin are involved in actin cytoskeleton organization and cell adhesion, suggesting possible significance of these binding partners in CPI-17-mediated cytoskeletal reorganization of endothelial cells. Furthermore, we confirmed the specific interaction between plakoglobin and CPI-17, which is affected by the phosphorylation status of CPI-17 in human lung microvascular endothelial cells.
Collapse
Affiliation(s)
- Kyung-mi Kim
- Vascular Biology Center, Georgia Health Sciences University, Augusta, GA, USA
| | | | | | | | | | | | | |
Collapse
|
24
|
GATA-6 and NF-κB activate CPI-17 gene transcription and regulate Ca2+ sensitization of smooth muscle contraction. Mol Cell Biol 2012; 33:1085-102. [PMID: 23275439 DOI: 10.1128/mcb.00626-12] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Protein kinase C (PKC)-potentiated inhibitory protein of 17 kDa (CPI-17) inhibits myosin light chain phosphatase, altering the levels of myosin light chain phosphorylation and Ca(2+) sensitivity in smooth muscle. In this study, we characterized the CPI-17 promoter and identified binding sites for GATA-6 and nuclear factor kappa B (NF-κB). GATA-6 and NF-κB upregulated CPI-17 expression in cultured human and mouse bladder smooth muscle (BSM) cells in an additive manner. CPI-17 expression was decreased upon GATA-6 silencing in cultured BSM cells and in BSM from NF-κB knockout (KO) mice. Moreover, force maintenance by BSM strips from KO mice was decreased compared with the force maintenance of BSM strips from wild-type mice. GATA-6 and NF-κB overexpression was associated with CPI-17 overexpression in BSM from men with benign prostatic hyperplasia (BPH)-induced bladder hypertrophy and in a mouse model of bladder outlet obstruction. Thus, aberrant expression of NF-κB and GATA-6 deregulates CPI-17 expression and the contractile function of smooth muscle. Our data provide insight into how GATA-6 and NF-κB mediate CPI-17 transcription, PKC-mediated signaling, and BSM remodeling associated with lower urinary tract symptoms in patients with BPH.
Collapse
|
25
|
Lontay B, Pál B, Serfőző Z, Kőszeghy Á, Szücs G, Rusznák Z, Erdődi F. Protein phosphatase-1M and Rho-kinase affect exocytosis from cortical synaptosomes and influence neurotransmission at a glutamatergic giant synapse of the rat auditory system. J Neurochem 2012; 123:84-99. [PMID: 22817114 DOI: 10.1111/j.1471-4159.2012.07882.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protein phosphatase-1M (PP1M, myosin phosphatase) consists of a PP1 catalytic subunit (PP1c) and the myosin phosphatase target subunit-1 (MYPT1). RhoA-activated kinase (ROK) regulates PP1M via inhibitory phosphorylation of MYPT1. Using multidisciplinary approaches, we have studied the roles of PP1M and ROK in neurotransmission. Electron microscopy demonstrated the presence of MYPT1 and ROK in both pre- and post-synaptic terminals. Tautomycetin (TMC), a PP1-specific inhibitor, decreased the depolarization-induced exocytosis from cortical synaptosomes. trans-4-[(1R)-1-aminoethyl]-N-4-pyridinylcyclohexanecarboxamide dihydrochloride, a ROK-specific inhibitor, had the opposite effect. Mass spectrometry analysis identified several MYPT1-bound synaptosomal proteins, of which interactions of synapsin-I, syntaxin-1, calcineurin-A subunit, and Ca(2+) /calmodulin-dependent kinase II with MYPT1 were confirmed. In intact synaptosomes, TMC increased, whereas Y27632 decreased the phosphorylation levels of MYPT1(Thr696) , myosin-II light chain(Ser19) , synapsin-I(Ser9) , and syntaxin-1(Ser14) , indicating that PP1M and ROK influence their phosphorylation status. Confocal microscopy indicated that MYPT1 and ROK are present in the rat ventral cochlear nucleus both pre- and post-synaptically. Analysis of the neurotransmission in an auditory glutamatergic giant synapse demonstrated that PP1M and ROK affect neurotransmission via both pre- and post-synaptic mechanisms. Our data suggest that both PP1M and ROK influence synaptic transmission, but further studies are needed to give a full account of their mechanism of action.
Collapse
Affiliation(s)
- Beáta Lontay
- Department of Medical Chemistry and Cell Biology and Signaling Research Group of the Hungarian Academy of Sciences, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
| | | | | | | | | | | | | |
Collapse
|
26
|
Wright DB, Tripathi S, Sikarwar A, Santosh KT, Perez-Zoghbi J, Ojo OO, Irechukwu N, Ward JPT, Schaafsma D. Regulation of GPCR-mediated smooth muscle contraction: implications for asthma and pulmonary hypertension. Pulm Pharmacol Ther 2012; 26:121-31. [PMID: 22750270 DOI: 10.1016/j.pupt.2012.06.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 06/15/2012] [Accepted: 06/18/2012] [Indexed: 11/28/2022]
Abstract
Contractile G-protein-coupled receptors (GPCRs) have emerged as key regulators of smooth muscle contraction, both under healthy and diseased conditions. This brief review will discuss some key topics and novel insights regarding GPCR-mediated airway and vascular smooth muscle contraction as discussed at the 7th International Young Investigators' Symposium on Smooth Muscle (2011, Winnipeg, Manitoba, Canada) and will in particular focus on processes driving Ca(2+)-mobilization and -sensitization.
Collapse
Affiliation(s)
- D B Wright
- Department of Asthma, Allergy, and Lung Biology, King's College, London, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
G-substrate: the cerebellum and beyond. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 106:381-416. [PMID: 22340725 DOI: 10.1016/b978-0-12-396456-4.00004-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The discovery of nitric oxide (NO) as an activator of soluble guanylate cyclase (sGC) has stimulated extensive research on the NO-sGC-3':5'-cyclic guanosine monophosphate (cGMP)-cGMP-dependent protein kinase (PKG) pathway. However, the restricted localization of pathway components and the lack of information on PKG substrates have hindered research seeking to examine the physiological roles of the NO-sGC-cGMP-PKG pathway. An excellent substrate for PKG is the G-substrate, which was originally discovered in the cerebellum. The role of G-substrate in the cerebellum and other brain structures has been revealed in recent years. This review discusses the relationship between the G-substrate and other components of the NO-sGC-cGMP-PKG pathway and describes the characteristics of the G-substrate gene and protein related to diseases. Finally, we discuss the physiological role of G-substrate in the cerebellum, where it regulates cerebellum-dependent long-term memory, and its role in the ventral tegmental area and retina, where it acts as an effective neuroprotectant.
Collapse
|
28
|
Ruiz-Loredo AY, López-Colomé AM. New insights into the regulation of myosin light chain phosphorylation in retinal pigment epithelial cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 293:85-121. [PMID: 22251559 DOI: 10.1016/b978-0-12-394304-0.00008-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The retinal pigment epithelium (RPE) plays an essential role in the function of the neural retina and the maintenance of vision. Most of the functions displayed by RPE require a dynamic organization of the acto-myosin cytoskeleton. Myosin II, a main cytoskeletal component in muscle and non-muscle cells, is directly involved in force generation required for organelle movement, selective molecule transport within cell compartments, exocytosis, endocytosis, phagocytosis, and cell division, among others. Contractile processes are triggered by the phosphorylation of myosin II light chains (MLCs), which promotes actin-myosin interaction and the assembly of contractile fibers. Considerable evidence indicates that non-muscle myosin II activation is critically involved in various pathological states, increasing the interest in studying the signaling pathways controlling MLC phosphorylation. Particularly, recent findings suggest a role for non-muscle myosin II-induced contraction in RPE cell transformation involved in the establishment of numerous retinal diseases. This review summarizes the current knowledge regarding myosin function in RPE cells, as well as the signaling networks leading to MLC phosphorylation under pathological conditions. Understanding the molecular mechanisms underlying RPE dysfunction would improve the development of new therapies for the treatment or prevention of different ocular disorders leading to blindness.
Collapse
Affiliation(s)
- Ariadna Yolanda Ruiz-Loredo
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico DF, Mexico
| | | |
Collapse
|
29
|
Nelson C, Glitsch MD. Lack of kinase regulation of canonical transient receptor potential 3 (TRPC3) channel-dependent currents in cerebellar Purkinje cells. J Biol Chem 2011; 287:6326-35. [PMID: 22207762 DOI: 10.1074/jbc.m111.246553] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Canonical transient receptor potential (TRPC) channels are widely expressed in the brain and play several roles in development and normal neuronal function. In the cerebellum, Purkinje cell TRPC3 channels underlie the slow excitatory postsynaptic potential observed after parallel fiber stimulation. In these cells TRPC3 channel opening requires stimulation of metabotropic glutamate receptor 1, activation of which can also lead to the induction of long term depression (LTD), which underlies cerebellar motor learning. LTD induction requires protein kinase C (PKC) and protein kinase G (PKG) activation, and although PKC phosphorylation targets are well established, virtually nothing is known about PKG targets in LTD. Because TRPC3 channels are inhibited after phosphorylation by PKC and PKG in expression systems, we examined whether native TRPC3 channels in Purkinje cells are a target for PKG or PKC, thereby contributing to cerebellar LTD. We find that in Purkinje cells, activation of TRPC3-dependent currents is not inhibited by conventional PKC or PKG to any significant extent and that inhibition of these kinases does not significantly impact on TRPC3-mediated currents either. Based on these and previous findings, we propose that TRPC3-dependent currents may differ significantly in their regulation from those overexpressed in expression systems.
Collapse
Affiliation(s)
- Charmaine Nelson
- Department of Physiology, Anatomy, and Genetics, Sherrington Building, Parks Road, Oxford Univerity, Oxford OX1 3PT, United Kingdom
| | | |
Collapse
|
30
|
Wagner W, McCroskery S, Hammer JA. An efficient method for the long-term and specific expression of exogenous cDNAs in cultured Purkinje neurons. J Neurosci Methods 2011; 200:95-105. [PMID: 21708190 DOI: 10.1016/j.jneumeth.2011.06.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 06/13/2011] [Indexed: 01/10/2023]
Abstract
We present a simple and efficient method for expressing cDNAs in Purkinje neurons (PNs) present in heterogeneous mouse cerebellar cultures. The method combines the transfection of freshly dissociated cerebellar cells via nucleofection with the use of novel expression plasmids containing a fragment of the L7 (Pcp2) gene that, within the cerebellum, drives PN-specific expression. The efficiency of PN transfection (determined 13 days post nucleofection) is approximately 70%. Double and triple transfections are routinely achieved at slightly lower efficiencies. Expression in PNs is obvious after one week in culture and still strong after three weeks, by which time these neurons are well-developed. Moreover, high-level expression is restricted almost exclusively to the PNs present in these mixed cultures, which greatly facilitates the characterization of PN-specific functions. As proof of principle, we used this method to visualize (1) the morphology of living PNs expressing mGFP, (2) the localization and dynamics of the dendritic spine proteins PSD-93 and Homer-3a tagged with mGFP and (3) the interaction of live PNs expressing mGFP with other cerebellar neurons expressing mCherry from a β-Actin promoter plasmid. Finally, we created a series of L7-plasmids containing different fluorescent protein cDNAs that are suited for the expression of cDNAs of interest as N- and C-terminally tagged fluorescent fusion proteins. In summary, this procedure allows for the highly efficient, long-term, and specific expression of multiple cDNAs in differentiated PNs, and provides a favorable alternative to two procedures (viral transduction, ballistic gene delivery) used previously to express genes in cultured PNs.
Collapse
Affiliation(s)
- Wolfgang Wagner
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | |
Collapse
|
31
|
Schonewille M, Belmeguenai A, Koekkoek SK, Houtman SH, Boele HJ, van Beugen BJ, Gao Z, Badura A, Ohtsuki G, Amerika WE, Hosy E, Hoebeek FE, Elgersma Y, Hansel C, De Zeeuw CI. Purkinje cell-specific knockout of the protein phosphatase PP2B impairs potentiation and cerebellar motor learning. Neuron 2010; 67:618-28. [PMID: 20797538 DOI: 10.1016/j.neuron.2010.07.009] [Citation(s) in RCA: 175] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2010] [Indexed: 11/29/2022]
Abstract
Cerebellar motor learning is required to obtain procedural skills. Studies have provided supportive evidence for a potential role of kinase-mediated long-term depression (LTD) at the parallel fiber to Purkinje cell synapse in cerebellar learning. Recently, phosphatases have been implicated in the induction of potentiation of Purkinje cell activities in vitro, but it remains to be shown whether and how phosphatase-mediated potentiation contributes to motor learning. Here, we investigated its possible role by creating and testing a Purkinje cell-specific knockout of calcium/calmodulin-activated protein-phosphatase-2B (L7-PP2B). The selective deletion of PP2B indeed abolished postsynaptic long-term potentiation in Purkinje cells and their ability to increase their excitability, whereas LTD was unaffected. The mutants showed impaired "gain-decrease" and "gain-increase" adaptation of their vestibulo-ocular reflex (VOR) as well as impaired acquisition of classical delay conditioning of their eyeblink response. Thus, our data indicate that PP2B may indeed mediate potentiation in Purkinje cells and contribute prominently to cerebellar motor learning.
Collapse
Affiliation(s)
- M Schonewille
- Department of Neuroscience, Erasmus MC, 3000 DR Rotterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Chiba Y, Tanabe M, Sakai H, Kimura S, Misawa M. A functional interaction between CPI-17 and RACK1 proteins in bronchial smooth muscle cells. Biochem Biophys Res Commun 2010; 401:487-90. [PMID: 20875397 DOI: 10.1016/j.bbrc.2010.09.086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 09/18/2010] [Indexed: 10/19/2022]
Abstract
CPI-17 is a phosphorylation-dependent inhibitor of smooth muscle myosin light chain. Using yeast two-hybrid system, we have identified the receptor for activated C kinase 1 (RACK1) as a novel interaction partner of CPI-17. The direct interaction and co-localization of CPI-17 with RACK1 were confirmed by immunoprecipitation and confocal microscopy analysis, respectively. An in vitro assay system using recombinant/purified proteins revealed that the PKC-mediated phosphorylation of CPI-17 was augmented in the presence of RACK1. These results suggest that RACK1 may play a role in PKC/CPI-17 signaling pathway.
Collapse
Affiliation(s)
- Yoshihiko Chiba
- Department of Pharmacology, School of Pharmacy, Hoshi University, Tokyo, Japan.
| | | | | | | | | |
Collapse
|
33
|
Takada N, Appel B. Identification of genes expressed by zebrafish oligodendrocytes using a differential microarray screen. Dev Dyn 2010; 239:2041-7. [PMID: 20549738 DOI: 10.1002/dvdy.22338] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Myelination of central nervous system axons requires that oligodendrocytes extend multiple membrane processes that specifically recognize and wrap axons, which is followed by expression of proteins necessary for formation of myelin sheaths. To identify new genes that might be important for myelination, we used microarrays to analyze the expression profiles of cells sorted from transgenic zebrafish embryos and larvae under conditions that permitted or blocked oligodendrocyte development. Here, we describe eight genes that have not been previously implicated in oligodendrocyte development. Among the predicted functions of proteins encoded by these genes are lipid sensing, cell-cell junction formation, cytoskeleton regulation, and intracellular signaling. The predicted functions raise the possibility that these genes are involved in multiple cellular events during oligodendrocyte differentiation and myelin formation.
Collapse
Affiliation(s)
- Norio Takada
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | | |
Collapse
|
34
|
Eto M. Regulation of cellular protein phosphatase-1 (PP1) by phosphorylation of the CPI-17 family, C-kinase-activated PP1 inhibitors. J Biol Chem 2010; 284:35273-7. [PMID: 19846560 DOI: 10.1074/jbc.r109.059972] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The regulatory circuit controlling cellular protein phosphatase-1 (PP1), an abundant group of Ser/Thr phosphatases, involves phosphorylation of PP1-specific inhibitor proteins. Malfunctions of these inhibitor proteins have been linked to a variety of diseases, including cardiovascular disease and cancer. Upon phosphorylation at Thr(38), the 17-kDa PP1 inhibitor protein, CPI-17, selectively inhibits a specific form of PP1, myosin light chain phosphatase, which transduces multiple kinase signals into the phosphorylation of myosin II and other proteins. Here, the mechanisms underlying PP1 inhibition and the kinase/PP1 cross-talk mediated by CPI-17 and its related proteins, PHI, KEPI, and GBPI, are discussed.
Collapse
Affiliation(s)
- Masumi Eto
- Department of Molecular Physiology and Biophysics and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
| |
Collapse
|
35
|
Kim JI, Young GD, Jin L, Somlyo AV, Eto M. Expression of CPI-17 in smooth muscle during embryonic development and in neointimal lesion formation. Histochem Cell Biol 2009; 132:191-8. [PMID: 19437030 DOI: 10.1007/s00418-009-0604-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/27/2009] [Indexed: 11/25/2022]
Abstract
Ca(2+) sensitivity of smooth muscle (SM) contraction is determined by CPI-17, an inhibitor protein for myosin light chain phosphatase (MLCP). CPI-17 is highly expressed in mature SM cells, but the expression level varies under pathological conditions. Here, we determined the expression of CPI-17 in embryonic SM tissues and arterial neointimal lesions using immunohistochemistry. As seen in adult animals, the predominant expression of CPI-17 was detected at SM tissues on mouse embryonic sections, whereas MLCP was ubiquitously expressed. Compared with SM alpha-actin, CPI-17 expression doubled in arterial SM from embryonic day E10 to E14. Like SM alpha-actin and other SM marker proteins, CPI-17 was expressed in embryonic heart, and the expression was down-regulated at E17. In adult rat, CPI-17 expression level was reduced to 30% in the neointima of injured rat aorta, compared with the SM layers, whereas the expression of MLCP was unchanged in both regions. Unlike other SM proteins, CPI-17 was detected at non-SM organs in the mouse embryo, such as embryonic neurons and epithelium. Thus, CPI-17 expression is reversibly controlled in response to the phenotype transition of SM cells that restricts the signal to differentiated SM cells and particular cell types.
Collapse
Affiliation(s)
- Jee In Kim
- Department of Molecular Physiology and Biophysics, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
| | | | | | | | | |
Collapse
|
36
|
Dual involvement of G-substrate in motor learning revealed by gene deletion. Proc Natl Acad Sci U S A 2009; 106:3525-30. [PMID: 19218432 DOI: 10.1073/pnas.0813341106] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this study, we generated mice lacking the gene for G-substrate, a specific substrate for cGMP-dependent protein kinase uniquely located in cerebellar Purkinje cells, and explored their specific functional deficits. G-substrate-deficient Purkinje cells in slices obtained at postnatal weeks (PWs) 10-15 maintained electrophysiological properties essentially similar to those from WT littermates. Conjunction of parallel fiber stimulation and depolarizing pulses induced long-term depression (LTD) normally. At younger ages, however, LTD attenuated temporarily at PW6 and recovered thereafter. In parallel with LTD, short-term (1 h) adaptation of optokinetic eye movement response (OKR) temporarily diminished at PW6. Young adult G-substrate knockout mice tested at PW12 exhibited no significant differences from their WT littermates in terms of brain structure, general behavior, locomotor behavior on a rotor rod or treadmill, eyeblink conditioning, dynamic characteristics of OKR, or short-term OKR adaptation. One unique change detected was a modest but significant attenuation in the long-term (5 days) adaptation of OKR. The present results support the concept that LTD is causal to short-term adaptation and reveal the dual functional involvement of G-substrate in neuronal mechanisms of the cerebellum for both short-term and long-term adaptation.
Collapse
|
37
|
Schnack C, Hengerer B, Gillardon F. Identification of novel substrates for Cdk5 and new targets for Cdk5 inhibitors using high-density protein microarrays. Proteomics 2008; 8:1980-6. [PMID: 18491313 DOI: 10.1002/pmic.200701063] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cyclin-dependent kinase (Cdk) 5 is a serine/threonine kinase that plays an important role during CNS development and its dysregulation is causally involved in the process of neuronal degeneration. To date more than 20 Cdk5 substrates have been identified and the number of Cdk5 substrates is still increasing. The different cellular functions of Cdk5 and its substrates are not completely known at present. High-throughput protein microarray technology is a powerful tool to identify a large number of potential kinase substrates in parallel under the same experimental conditions. Using Protoarray protein microarrays we identified protein phosphatase 1, regulatory subunit 14A (PPP1R14A) as a novel substrate of Cdk5/p25. Phosphorylation was confirmed in two secondary assays. Our findings may contribute to the elucidation of the physiological function of Cdk5 in synaptic signalling. Functional Kinome Arrays were validated in a second set of experiments to characterize the selectivity of the Cdk5 inhibitor indolinone A. This lead to the identification of two additional kinases that are targeted by this compound and may provide a deeper understanding of its neuroprotective mode of action. However, several false negative results possibly due to a denatured or inactive conformation of the arrayed proteins, sound a note of caution when using protein array techniques.
Collapse
Affiliation(s)
- Cathrin Schnack
- Boehringer Ingelheim Pharma GmbH & Co. KG, CNS Research, Biberach an der Riss, Germany
| | | | | |
Collapse
|
38
|
Eto M, Kitazawa T, Matsuzawa F, Aikawa SI, Kirkbride JA, Isozumi N, Nishimura Y, Brautigan DL, Ohki SY. Phosphorylation-induced conformational switching of CPI-17 produces a potent myosin phosphatase inhibitor. Structure 2007; 15:1591-602. [PMID: 18073109 PMCID: PMC2217667 DOI: 10.1016/j.str.2007.10.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Revised: 10/02/2007] [Accepted: 10/03/2007] [Indexed: 11/17/2022]
Abstract
Phosphorylation of endogenous inhibitor proteins for type-1 Ser/Thr phosphatase (PP1) provides a mechanism for reciprocal coordination of kinase and phosphatase activities. A myosin phosphatase inhibitor protein CPI-17 is phosphorylated at Thr38 through G-protein-mediated signals, resulting in a >1000-fold increase in inhibitory potency. We show here the solution NMR structure of phospho-T38-CPI-17 with rmsd of 0.36 +/- 0.06 A for the backbone secondary structure, which reveals how phosphorylation triggers a conformational change and exposes an inhibitory surface. This active conformation is stabilized by the formation of a hydrophobic core of intercalated side chains, which is not formed in a phospho-mimetic D38 form of CPI-17. Thus, the profound increase in potency of CPI-17 arises from phosphorylation, conformational change, and hydrophobic stabilization of a rigid structure that poses the phosphorylated residue on the protein surface and restricts its hydrolysis by myosin phosphatase. Our results provide structural insights into transduction of kinase signals by PP1 inhibitor proteins.
Collapse
Affiliation(s)
- Masumi Eto
- Department of Molecular Physiology and Biophysics, Thomas Jefferson University, 1020 Locust Street, Philadelphia, Pennsylvania 19107, USA
| | - Toshio Kitazawa
- Boston Biomedical Research Institute, 64 Grove Street, Watertown, Massachusetts, USA
| | - Fumiko Matsuzawa
- Dept Clinical Genetics, Tokyo Metropolitan Institute of Medical Science, Honkomagome 3-18-22, Bunkyo-ku, Tokyo 113-8613, Japan
| | - Sei-ichi Aikawa
- Dept Clinical Genetics, Tokyo Metropolitan Institute of Medical Science, Honkomagome 3-18-22, Bunkyo-ku, Tokyo 113-8613, Japan
| | - Jason A. Kirkbride
- Department of Molecular Physiology and Biophysics, Thomas Jefferson University, 1020 Locust Street, Philadelphia, Pennsylvania 19107, USA
| | - Noriyoshi Isozumi
- Center for Nano Materials and Technology (CNMT), Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Tatsunokuchi, Ishikawa, 923-1292, Japan
| | - Yumi Nishimura
- Center for Nano Materials and Technology (CNMT), Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Tatsunokuchi, Ishikawa, 923-1292, Japan
| | - David L. Brautigan
- Center for Cell Signaling, University of Virginia School of Medicine, 1400 Jefferson Park Avenue, Charlottesville, Virginia 22908, USA
| | - Shin-ya Ohki
- Center for Nano Materials and Technology (CNMT), Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Tatsunokuchi, Ishikawa, 923-1292, Japan
| |
Collapse
|
39
|
Abstract
A major goal of learning and memory research is to correlate the function of molecules with the behaviour of organisms. The beautiful laminar structure of the cerebellar cortex lends itself to the study of synaptic plasticity, because its clearly defined patterns of neurons and their synapses form circuits that have been implicated in simple motor behaviour paradigms. The best understood in terms of molecular mechanism is the parallel fibre-Purkinje cell synapse, where presynaptic long-term potentiation and postsynaptic long-term depression and potentiation finely tune cerebellar output. Our understanding of these forms of plasticity has mostly come from the electrophysiological and behavioural analysis of knockout mutant mice, but more recently the knock-in of synaptic molecules with mutated phosphorylation sites and binding domains has provided more detailed insights into the signalling events. The present review details the major forms of plasticity in the cerebellar cortex, with particular attention to the membrane trafficking and intracellular signalling responsible. This overview of the current literature suggests it will not be long before the involvement of the cerebellum in certain motor behaviours is fully explained in molecular terms.
Collapse
Affiliation(s)
- Gareth J O Evans
- Department of Biology (Area 3), University of York, Heslington, York, UK.
| |
Collapse
|
40
|
Schmolesky MT, De Ruiter MM, De Zeeuw CI, Hansel C. The neuropeptide corticotropin-releasing factor regulates excitatory transmission and plasticity at the climbing fibre-Purkinje cell synapse. Eur J Neurosci 2007; 25:1460-6. [PMID: 17425571 DOI: 10.1111/j.1460-9568.2007.05409.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The climbing fibre (CF) input controls cerebellar Purkinje cell (PC) activity as well as synaptic plasticity at parallel fibre (PF)-PC synapses. Under high activity conditions, CFs release not only glutamate, but also the neuropeptide corticotropin-releasing factor (CRF). Brief periods of such high CF activity can lead to the induction of long-term depression (LTD) at CF-PC synapses. Thus, we have examined for the first time the role of CRF in regulating excitatory postsynaptic currents (EPSCs) and long-term plasticity at this synapse. Exogenous application of CRF alone transiently mimicked three aspects of CF-LTD, causing reductions in the CF-evoked excitatory postsynaptic current, complex spike second component and complex spike afterhyperpolarization. The complex spike first component is unaffected by CF-LTD induction and was similarly unaffected by CRF. Application of a CRF receptor antagonist reduced the expression amplitude and induction probability of CF-LTD monitored at the EPSC level. Collectively, these results suggest that under particular sensorimotor conditions, co-release of CRF from climbing fibres could down-regulate excitatory transmission and facilitate LTD induction at CF-PC synapses. Inhibition of either protein kinase C (PKC) or protein kinase A (PKA) attenuated the effects of CRF upon CF-EPSCs. We have previously shown that CF-LTD induction is PKC-dependent, and here demonstrate PKA-dependence as well. These results suggest that both the acute effects of CRF on CF-EPSCs as well as the facilitating effect of CRF on CF-LTD induction can be explained by a CRF-mediated recruitment of PKC and PKA.
Collapse
Affiliation(s)
- M T Schmolesky
- Department of Neuroscience, Erasmus University Medical Centre, Postbus 2040, 3000 CA Rotterdam, The Netherlands
| | | | | | | |
Collapse
|
41
|
Tsuruno S, Hirano T. Persistent activation of protein kinase Calpha is not necessary for expression of cerebellar long-term depression. Mol Cell Neurosci 2007; 35:38-48. [PMID: 17363267 DOI: 10.1016/j.mcn.2007.01.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Revised: 01/05/2007] [Accepted: 01/30/2007] [Indexed: 10/23/2022] Open
Abstract
Protein kinase Calpha (PKCalpha) plays a major role in the induction of long-term depression (LTD) in a cerebellar Purkinje cell (PC). The sequential activation model for classical PKC states that PKCalpha translocates to the plasma membrane by binding Ca(++) and then becomes fully activated by binding diacylglycerol (DAG), which enables estimation of the activity by monitoring its localization. Here, we performed simultaneous electrophysiological recording and fluorescence imaging in a cultured PC expressing GFP-tagged PKCalpha. When a PC was depolarized, PKCalpha transiently translocated to the plasma membrane in a Ca(++)-dependent manner. Application of membrane permeable DAG or the blocker of DAG lipase prolonged the translocation. These results suggest that the sequential activation model is applicable to PCs. Conjunctive applications of glutamate and depolarization pulse induced LTD, but did not prolong the translocation. Thus, our results imply that persistent activation of PKCalpha is not necessary for the expression of LTD.
Collapse
Affiliation(s)
- S Tsuruno
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | | |
Collapse
|
42
|
Jörntell H, Hansel C. Synaptic memories upside down: bidirectional plasticity at cerebellar parallel fiber-Purkinje cell synapses. Neuron 2007; 52:227-38. [PMID: 17046686 DOI: 10.1016/j.neuron.2006.09.032] [Citation(s) in RCA: 253] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Information storage in neural circuits depends on activity-dependent alterations in synaptic weights, such as long-term potentiation (LTP) and long-term depression (LTD). Bidirectional synaptic plasticity endows synapses with mechanisms for rapid reversibility, but it remains unclear how it correlates with reversibility in behavioral learning and whether there is a universal synaptic memory mechanism that operates similarly at all types of synapses. A recently discovered postsynaptic form of LTP at cerebellar parallel fiber (PF)-Purkinje cell (PC) synapses provides a reversal mechanism for PF-LTD and enables a fresh look at the implications of bidirectional plasticity in a brain structure that is particularly suitable to correlate cellular to behavioral learning events. Here, we will review recent studies that reveal unique properties of bidirectional cerebellar plasticity and suggest that the induction cascades for cerebellar LTP and LTD provide a mirror image of their counterparts at hippocampal synapses. We will also discuss how PF-LTP helps to explain reversibility observed in cerebellar motor learning.
Collapse
Affiliation(s)
- Henrik Jörntell
- Department of Experimental Medical Science, Section for Neuroscience, Lund University, BMC F10 Tornavägen 10, SE-221 84 Lund, Sweden
| | | |
Collapse
|
43
|
Yamaguchi Y, Shirai Y, Matsubara T, Sanse K, Kuriyama M, Oshiro N, Yoshino KI, Yonezawa K, Ono Y, Saito N. Phosphorylation and Up-regulation of Diacylglycerol Kinase γ via Its Interaction with Protein Kinase Cγ. J Biol Chem 2006. [DOI: 10.1016/s0021-9258(19)84076-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
44
|
Huang Y, Lu MQ, Li H, Xu C, Yi SH, Chen GH. Occurrence of cGMP/nitric oxide-sensitive store-operated calcium entry in fibroblasts and its effect on matrix metalloproteinase secretion. World J Gastroenterol 2006; 12:5483-9. [PMID: 17006985 PMCID: PMC4088230 DOI: 10.3748/wjg.v12.i34.5483] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To examine the existence of Nitric oxide/cGMP sensitive store-operated Ca2+ entry in mouse fibroblast NIH/3T3 cells and its influence on matrix metalloproteinase (MMP) production and adhesion ability of fibroblasts.
METHODS: NIH/3T3 cells were cultured. Confocal laser scanning microscopy was used to examine the existence of thapsigargin-induced store-operated Ca2+ entry in fibroblasts. Gelatin zymography and semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) were employed to detect the involvement of [Ca2+]i and NO/cGMP in MMP secretion. The involvement of NO/cGMP-sensitive Ca2+ entry in adhesion was determined using matrigel-coated culture plates.
RESULTS: 8-bromo-cGMP inhibited the thapsigargin-induced Ca2+ entry in 3T3 cells. The cGMP-induced inhibition was abolished by an inhibitor of protein kinase G, KT5823 (1μmol/L). A similar effect on the Ca2+ entry was observed in 3T3 cells in response to a NO donor, (±)-S-nitroso-N-acetylpenicillamine (SNAP). The inhibitory effect of SNAP on the thapsigargin-induced Ca2+ entry was also observed, indicating NO/cGMP-regulated Ca2+ entry in 3T3 cells. Results of gelatin zymography assay showed that addition of extracellular Ca2+ concentration induced MMP release and activation in a dose-dependent manner. RT-PCR also showed that cGMP and SNAP reduced the production of MMP mRNA in 3T3 cells. Experiments investigating adhesion potentials demonstrated that cGMP and SNAP could upgrade 3T3 cell attachment rate to the matrigel-coated culture plates.
CONCLUSION: NO/cGMP sensitive store-operated Ca2+ entry occurs in fibroblasts, and attenuates their adhesion potentials through its influence on MMP secretion.
Collapse
Affiliation(s)
- Yong Huang
- Liver Transplantation Centre, the Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, Guangdong Province, China
| | | | | | | | | | | |
Collapse
|
45
|
Yamaguchi Y, Shirai Y, Matsubara T, Sanse K, Kuriyama M, Oshiro N, Yoshino KI, Yonezawa K, Ono Y, Saito N. Phosphorylation and Up-regulation of Diacylglycerol Kinase γ via Its Interaction with Protein Kinase Cγ. J Biol Chem 2006; 281:31627-37. [PMID: 16905533 DOI: 10.1074/jbc.m606992200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Diacylglycerol (DAG) acts as an allosteric activator of protein kinase C (PKC) and is converted to phosphatidic acid by DAG kinase (DGK). Therefore, DGK is thought to be a negative regulator of PKC activation. Here we show molecular mechanisms of functional coupling of the two kinases. gammaPKC directly associated with DGKgamma through its accessory domain (AD), depending on Ca2+ as well as phosphatidylserine/diolein in vitro. Mass spectrometric analysis and mutation studies revealed that gammaPKC phosphorylated Ser-776 and Ser-779 in the AD of DGKgamma. The phosphorylation by gammaPKC resulted in activation of DGKgamma because a DGKgamma mutant in which Ser-776 and Ser-779 were substituted with glutamic acid to mimic phosphorylation exhibited significantly higher activity compared with wild type DGKgamma and an unphosphorylatable DGKgamma mutant. Importantly, the interaction of the two kinases and the phosphorylation of DGKgamma by gammaPKC could be confirmed in vivo, and overexpression of the AD of DGKgamma inhibited re-translocation of gammaPKC. These results demonstrate that localization and activation of the functionally correlated kinases, gammaPKC and DGKgamma, are spatio-temporally orchestrated by their direct association and phosphorylation, contributing to subtype-specific regulation of DGKgamma and DAG signaling.
Collapse
Affiliation(s)
- Yasuto Yamaguchi
- Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Tatsukawa T, Chimura T, Miyakawa H, Yamaguchi K. Involvement of basal protein kinase C and extracellular signal-regulated kinase 1/2 activities in constitutive internalization of AMPA receptors in cerebellar Purkinje cells. J Neurosci 2006; 26:4820-5. [PMID: 16672655 PMCID: PMC6674172 DOI: 10.1523/jneurosci.0535-06.2006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AMPA receptor (AMPAR) internalization provides a mechanism for long-term depression (LTD) in both hippocampal pyramidal neurons and cerebellar Purkinje cells (PCs). Cerebellar LTD at the parallel fiber (PF)-PC synapse is the underlying basis of motor learning and requires AMPAR activation, a large Ca2+ influx, and protein kinase C (PKC) activation. However, whether these requirements affect the constitutive AMPAR internalization in PF-PC synapses remains unclarified. Tetanus toxin (TeTx) infusion into PCs decreased PF-EPSC amplitude to 60% within 20-30 min (TeTx rundown), without change in paired-pulse facilitation ratio or receptor kinetics. Immunocytochemically measured glutamate receptor 2 (GluR2) internalization ratio decreased at the steady state of TeTx rundown. TeTx rundown did not require AMPAR activity nor an increase in intracellular Ca2+ concentration. TeTx rundown was suppressed partially by the inhibition of either conventional PKC or mitogen-activated protein kinase kinase (MEK) and completely by the inhibition of both kinases. The background PKC activity was shown to be sufficient, because a PKC activator did not facilitate TeTx rundown. The inhibition of protein phosphatase 1/2A (PP1/2A) enhanced TeTx rundown slightly, and both inhibition of PP1/2A and activation of PKC maximized it, but one-half of AMPARs at PF-PC synapses remained in the TeTx-resistant pool. The inhibition of actin depolymerization suppressed TeTx rundown and decreased the GluR2 internalization ratio. In contrast, the inhibition of actin polymerization enhanced TeTx rundown and increased the GluR2 internalization ratio. We suggest that the regulation of actin polymerization is involved in the surface expression of AMPARs and the surface expressing AMPARs are constitutively internalized through both basal PKC and MEK-ERK1/2 (extracellular signal-regulated kinase 1/2) activities at PF-PC synapses.
Collapse
|
47
|
Belmeguenai A, Hansel C. A role for protein phosphatases 1, 2A, and 2B in cerebellar long-term potentiation. J Neurosci 2006; 25:10768-72. [PMID: 16291950 PMCID: PMC6725852 DOI: 10.1523/jneurosci.2876-05.2005] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cerebellar parallel fiber (PF)-Purkinje cell (PC) synapses can undergo postsynaptically expressed long-term depression (LTD) or long-term potentiation (LTP). PF-LTD induction requires the coactivity of the PF and CF (climbing fiber) inputs to PCs and a concomitant calcium transient and activation of protein kinase C (PKC). PF-LTP can be induced by PF activity alone and requires a lower calcium transient for its induction than PF-LTD. The cellular events triggering PF-LTP induction are not well characterized. At other types of synapses (e.g., in the hippocampus), bidirectional synaptic plasticity is under control of a kinase/phosphatase switch, with PKC and CaMKII (calcium/calmodulin-dependent kinase II) activity promoting LTP induction and phosphatase activity promoting LTD induction. Here, we have tested for the involvement of protein phosphatase 1 (PP1), PP2A, and PP2B (calcineurin) in cerebellar LTP induction using whole-cell patch-clamp recordings in rat cerebellar slices. LTP induction was blocked in the presence of the PP1/2A inhibitors okadaic acid and microcystin LR, the PP1 inhibitory peptide inhibitor-2, the PP2A inhibitor fostriecin, and the PP2B inhibitor cyclosporin A. LTP induction was not impaired by the PKC inhibitor chelerythrine. Conversely, LTD induction was not blocked by microcystin LR but instead was reduced when active PP2B was injected into PCs. These data indicate that a kinase/phosphatase switch controls bidirectional cerebellar plasticity, but in a manner "inverse" to the dependencies found at other types of synapses. Therefore, cerebellar LTP constitutes the only form of LTP described so far that depends on phosphatase rather than kinase activity.
Collapse
Affiliation(s)
- Amor Belmeguenai
- Department of Neuroscience, Erasmus University Medical Center, 3000 DR Rotterdam, The Netherlands
| | | |
Collapse
|
48
|
Anwyl R. Induction and expression mechanisms of postsynaptic NMDA receptor-independent homosynaptic long-term depression. Prog Neurobiol 2006; 78:17-37. [PMID: 16423442 DOI: 10.1016/j.pneurobio.2005.12.001] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Revised: 11/21/2005] [Accepted: 12/01/2005] [Indexed: 12/20/2022]
Abstract
The induction of long-term depression (LTD) can be divided into two main forms, one dependent upon activation of postsynaptic NMDAR, and another independent of postsynaptic NMDAR. Non-postsynaptic NMDAR-LTD (non-NMDAR-LTD) occurs in many regions of the brain, and encompasses a wide variety of induction and expression mechanisms. In this article, the induction and expression mechanisms of such LTD in over 10 brain regions are described, with a number of common mechanisms compared across a large range of types of LTD. The article describes the involvement of different presynaptic or postsynaptic receptors in the induction of non-NMDAR-LTD, especially metabotropic glutamate receptors, cannabinoid receptors and dopamine receptors. An increase in presynaptic or postsynaptic intracellular Ca concentration is a key event in induction, commonly followed by activation of certain kinases, especially PKC, p38 MAPK and ERK. Expression mechanisms are either presynaptic via a reduction in release probability, or postsynaptic involving a decrease in AMPAR via phosphorylation of a glutamate receptor subunit, especially GluR2, followed by clathrin-mediated endocytosis. Retrograde signalling from postsynaptic to presynaptic occurs when induction is postsynaptic and expression is presynaptic.
Collapse
Affiliation(s)
- Roger Anwyl
- Department of Physiology, Trinity College, Dublin 2, Ireland.
| |
Collapse
|
49
|
Shin JH, Linden DJ. An NMDA Receptor/Nitric Oxide Cascade Is Involved in Cerebellar LTD But Is Not Localized to the Parallel Fiber Terminal. J Neurophysiol 2005; 94:4281-9. [PMID: 16120658 DOI: 10.1152/jn.00661.2005] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Long-term depression (LTD) of the parallel fiber-Purkinje cell synapse in the cerebellum is a cellular model system that has been suggested to underlie certain forms of motor learning. Induction of cerebellar LTD requires a postsynaptic kinase limb involving activation of mGluR1, protein kinase Cα (PKCα), and phosphorylation of ser-880 on the AMPA receptor subunit GluR2. Several lines of evidence have also implicated a complementary phosphatase limb in which N-methyl-d-aspartate (NMDA) receptor-mediated Ca2+ influx activates neuronal nitric oxide synthase (nNOS), the ultimate consequences of which are mediated by nitric oxide (NO), cGMP, and inhibition of postsynaptic protein phosphatases. However, the cellular localization of an NMDA/NO cascade has been complicated by the fact that neither functional NMDA receptors nor nNOS are expressed in Purkinje cells. This has lead to a proposal in which NMDA receptors activate nNOS in parallel fibers. Here, we confirm that pharmacological blockade of NMDA receptor or NO signaling blocks induction of LTD. However, no evidence was found for functional NMDA receptors in parallel fiber terminals: blockade of NMDA receptors did not alter either presynaptic Ca2+ transients or the frequency of miniature excitatory postsynaptic currents. NMDA receptor blockade did abolish a slow depolarization evoked by burst stimulation of parallel fiber-stellate cell synapses. The application of NMDA evoked a Ca2+ transient in stellate cell terminals but not in parallel fiber terminals. These results are consistent with the hypothesis that an NMDA receptor/NO cascade involved in cerebellar LTD is localized to interneurons rather than parallel fibers.
Collapse
Affiliation(s)
- Jung Hoon Shin
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | |
Collapse
|
50
|
De Zeeuw CI, Yeo CH. Time and tide in cerebellar memory formation. Curr Opin Neurobiol 2005; 15:667-74. [PMID: 16271462 DOI: 10.1016/j.conb.2005.10.008] [Citation(s) in RCA: 163] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Accepted: 10/21/2005] [Indexed: 10/25/2022]
Abstract
The notion that the olivocerebellar system is crucial for motor learning is well established. In recent years, it has become evident that there can be many forms of both synaptic and non-synaptic plasticity within this system and that each might have a different role in developing and maintaining motor learning across a wide range of tasks. There are several possible molecular and cellular mechanisms that could underlie adaptation of the vestibulo-ocular reflex and eyeblink conditioning. Although causal relationships between particular cellular processes and individual components of a learned behaviour have not been demonstrated unequivocally, an overall picture is emerging that the different types and sites of cellular plasticity relate importantly to the stage of learning and/or its temporal specifics.
Collapse
Affiliation(s)
- Chris I De Zeeuw
- Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands.
| | | |
Collapse
|