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Gupta S, Mukherjee S, Syed P, Pandala NG, Choudhary S, Singh VA, Singh N, Zhu H, Epari S, Noronha SB, Moiyadi A, Srivastava S. Evaluation of autoantibody signatures in meningioma patients using human proteome arrays. Oncotarget 2017; 8:58443-58456. [PMID: 28938569 PMCID: PMC5601665 DOI: 10.18632/oncotarget.16997] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 03/11/2017] [Indexed: 12/26/2022] Open
Abstract
Meningiomas are one of the most common tumors of the Central nervous system (CNS). This study aims to identify the autoantibody biomarkers in meningiomas using high-density human proteome arrays (~17,000 full-length recombinant human proteins). Screening of sera from 15 unaffected healthy individuals, 10 individuals with meningioma grade I and 5 with meningioma grade II was performed. This comprehensive proteomics based investigation revealed the dysregulation of 489 and 104 proteins in grades I and II of meningioma, respectively, along with the enrichment of several signalling pathways, which might play a crucial role in the manifestation of the disease. Autoantibody targets like IGHG4, CRYM, EFCAB2, STAT6, HDAC7A and CCNB1 were significantly dysregulated across both the grades. Further, we compared this to the tissue proteome and gene expression profile from GEO database. Previously reported upregulated proteins from meningioma tissue-based proteomics obtained from high-resolution mass spectrometry demonstrated an aggravated autoimmune response, emphasizing the clinical relevance of these targets. Some of these targets like SELENBP1 were tested for their presence in tumor tissue using immunoblotting. In the light of highly invasive diagnostic modalities employed to diagnose CNS tumors like meningioma, these autoantibody markers offer a minimally invasive diagnostic platform which could be pursued further for clinical translation.
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Affiliation(s)
- Shabarni Gupta
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Shuvolina Mukherjee
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Parvez Syed
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India.,Department of Biochemistry/Biotechnology, University of Turku, Turun yliopisto, Finland
| | - Narendra Goud Pandala
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Saket Choudhary
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India.,Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Vedita Anand Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Namrata Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Heng Zhu
- Department of Pharmacology and Molecular Sciences/High-Throughput Biology Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sridhar Epari
- Department of Pathology, Tata Memorial Centre, Mumbai, India
| | - Santosh B Noronha
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India
| | | | - Sanjeeva Srivastava
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
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2
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Trejter M, Hochol A, Tyczewska M, Ziolkowska A, Jopek K, Szyszka M, Malendowicz LK, Rucinski M. Visinin-like peptide 1 in adrenal gland of the rat. Gene expression and its hormonal control. Peptides 2015; 63:22-9. [PMID: 25451331 DOI: 10.1016/j.peptides.2014.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 10/29/2014] [Accepted: 10/29/2014] [Indexed: 10/24/2022]
Abstract
VSNL1 encodes the calcium-sensor protein visinin-like 1 and was identified previously as an upregulated gene in a sample set of aldosterone-producing adenomas. Recently, by means of microarray studies we demonstrated high expression of Vsnl1 gene in rat adrenal zona glomerulosa (ZG). Only scanty data are available on the role of this gene in adrenal function as well as on regulation of its expression by factors affecting adrenal cortex structure and function. Therefore we performed relevant studies aimed at clarifying some of the above issues. By Affymetrix(®) Rat Gene 1.1 ST Array Strip, QPCR and immunohistochemistry we demonstrated that expression levels of Vsnl1 in the rat adrenal ZG are notably higher than in the fasciculata/reticularis zone. In QPCR assay this difference was approximately 10 times higher. Expression of this gene in the rat adrenal gland or adrenocortical cells was acutely down regulated by ACTH, while chronic administration of corticotrophin or dexamethasone did not change Vsnl1 mRNA levels. In enucleation-induced adrenocortical regeneration expression levels of both Vsnl1 and Cyp11b2 were notably lowered and positively correlated. Despite these findings, the physiological significance of adrenal Vsnl1 remains unclear, and requires further investigation.
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Affiliation(s)
- Marcin Trejter
- Department of Histology and Embryology, Poznań University of Medical Sciences, Poznań, Poland
| | - Anna Hochol
- Department of Histology and Embryology, Poznań University of Medical Sciences, Poznań, Poland
| | - Marianna Tyczewska
- Department of Histology and Embryology, Poznań University of Medical Sciences, Poznań, Poland
| | - Agnieszka Ziolkowska
- Department of Histology and Embryology, Poznań University of Medical Sciences, Poznań, Poland
| | - Karol Jopek
- Department of Histology and Embryology, Poznań University of Medical Sciences, Poznań, Poland
| | - Marta Szyszka
- Department of Histology and Embryology, Poznań University of Medical Sciences, Poznań, Poland
| | - Ludwik K Malendowicz
- Department of Histology and Embryology, Poznań University of Medical Sciences, Poznań, Poland.
| | - Marcin Rucinski
- Department of Histology and Embryology, Poznań University of Medical Sciences, Poznań, Poland
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Integration of high-volume molecular and imaging data for composite biomarker discovery in the study of melanoma. BIOMED RESEARCH INTERNATIONAL 2014; 2014:145243. [PMID: 24527435 PMCID: PMC3914284 DOI: 10.1155/2014/145243] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 09/28/2013] [Accepted: 10/12/2013] [Indexed: 12/19/2022]
Abstract
In this work the effects of simple imputations are studied, regarding the integration of multimodal data originating from different patients. Two separate datasets of cutaneous melanoma are used, an image analysis (dermoscopy) dataset together with a transcriptomic one, specifically DNA microarrays. Each modality is related to a different set of patients, and four imputation methods are employed to the formation of a unified, integrative dataset. The application of backward selection together with ensemble classifiers (random forests), followed by principal components analysis and linear discriminant analysis, illustrates the implication of the imputations on feature selection and dimensionality reduction methods. The results suggest that the expansion of the feature space through the data integration, achieved by the exploitation of imputation schemes in general, aids the classification task, imparting stability as regards the derivation of putative classifiers. In particular, although the biased imputation methods increase significantly the predictive performance and the class discrimination of the datasets, they still contribute to the study of prominent features and their relations. The fusion of separate datasets, which provide a multimodal description of the same pathology, represents an innovative, promising avenue, enhancing robust composite biomarker derivation and promoting the interpretation of the biomedical problem studied.
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Braunewell KH. The visinin-like proteins VILIP-1 and VILIP-3 in Alzheimer's disease-old wine in new bottles. Front Mol Neurosci 2012; 5:20. [PMID: 22375104 PMCID: PMC3284765 DOI: 10.3389/fnmol.2012.00020] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 02/09/2012] [Indexed: 01/08/2023] Open
Abstract
The neuronal Ca2+-sensor (NCS) proteins VILIP-1 and VILIP-3 have been implicated in the etiology of Alzheimer's disease (AD). Genome-wide association studies (GWAS) show association of genetic variants of VILIP-1 (VSNL1) and VILIP-3 (HPCAL1) with AD+P (+psychosis) and late onset AD (LOAD), respectively. In AD brains the expression of VILIP-1 and VILIP-3 protein and mRNA is down-regulated in cortical and limbic areas. In the hippocampus, for instance, reduced VILIP-1 mRNA levels correlate with the content of neurofibrillary tangles (NFT) and amyloid plaques, the pathological characteristics of AD, and with the mini mental state exam (MMSE), a test for cognitive impairment. More recently, VILIP-1 was evaluated as a cerebrospinal fluid (CSF) biomarker and a prognostic marker for cognitive decline in AD. In CSF increased VILIP-1 levels correlate with levels of Aβ, tau, ApoE4, and reduced MMSE scores. These findings tie in with previous results showing that VILIP-1 is involved in pathological mechanisms of altered Ca2+-homeostasis leading to neuronal loss. In PC12 cells, depending on co-expression with the neuroprotective Ca2+-buffer calbindin D28K, VILIP-1 enhanced tau phosphorylation and cell death. On the other hand, VILIP-1 affects processes, such as cyclic nucleotide signaling and dendritic growth, as well as nicotinergic modulation of neuronal network activity, both of which regulate synaptic plasticity and cognition. Similar to VILIP-1, its interaction partner α4β2 nicotinic acetylcholine receptor (nAChR) is severely reduced in AD, causing severe cognitive deficits. Comparatively little is known about VILIP-3, but its interaction with cytochrome b5, which is part of an antioxidative system impaired in AD, hint toward a role in neuroprotection. A current hypothesis is that the reduced expression of visinin-like protein (VSNLs) in AD is caused by selective vulnerability of subpopulations of neurons, leading to the death of these VILIP-1-expressing neurons, explaining its increased CSF levels. While the Ca2+-sensor appears to be a good biomarker for the detrimental effects of Aβ in AD, its early, possibly Aβ-induced, down-regulation of expression may additionally attenuate neuronal signal pathways regulating the functions of dendrites and neuroplasticity, and as a consequence, this may contribute to cognitive decline in early AD.
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Affiliation(s)
- Karl H Braunewell
- Molecular and Cellular Neuroscience Laboratory, Department Biochemistry and Molecular Biology, Southern Research Institute, Birmingham AL, USA
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5
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Beheshti B, Braude I, Marrano P, Thorner P, Zielenska M, Squire JA. Chromosomal localization of DNA amplifications in neuroblastoma tumors using cDNA microarray comparative genomic hybridization. Neoplasia 2003; 5:53-62. [PMID: 12659670 PMCID: PMC1502121 DOI: 10.1016/s1476-5586(03)80017-9] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Conventional comparative genomic hybridization (CGH) profiling of neuroblastomas has identified many genomic aberrations, although the limited resolution has precluded a precise localization of sequences of interest within amplicons. To map high copy number genomic gains in clinically matched stage IV neuroblastomas, CGH analysis using a 19,200-feature cDNA microarray was used. A dedicated (freely available) algorithm was developed for rapid in silico determination of chromosomal localizations of microarray cDNA targets, and for generation of an ideogram-type profile of copy number changes. Using these methodologies, novel gene amplifications undetectable by chromosome CGH were identified, and larger MYCN amplicon sizes (in one tumor up to 6 Mb) than those previously reported in neuroblastoma were identified. The genes HPCAL1, LPIN1/KIAA0188, NAG, and NSE1/LOC151354 were found to be coamplified with MYCN. To determine whether stage IV primary tumors could be further subclassified based on their genomic copy number profiles, hierarchical clustering was performed. Cluster analysis of microarray CGH data identified three groups: 1) no amplifications evident, 2) a small MYCN amplicon as the only detectable imbalance, and 3) a large MYCN amplicon with additional gene amplifications. Application of CGH to cDNA microarray targets will help to determine both the variation of amplicon size and help better define amplification-dependent and independent pathways of progression in neuroblastoma.
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Affiliation(s)
- Ben Beheshti
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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6
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Lin L, Jeanclos EM, Treuil M, Braunewell KH, Gundelfinger ED, Anand R. The calcium sensor protein visinin-like protein-1 modulates the surface expression and agonist sensitivity of the alpha 4beta 2 nicotinic acetylcholine receptor. J Biol Chem 2002; 277:41872-8. [PMID: 12202488 DOI: 10.1074/jbc.m206857200] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The calcium sensor protein visinin-like protein-1 (VILIP-1) was isolated from a brain cDNA yeast two-hybrid library using the large cytoplasmic domain of the alpha4 subunit as a bait. VILIP-1 is a myristoylated calcium sensor protein that contains three functional calcium binding EF-hand motifs. The alpha4 subunit residues 302-339 were found to be essential for the interaction with VILIP-1. VILIP-1 coimmunopurified with detergent-solubilized recombinant alpha4beta2 acetylcholine receptors (AChRs) expressed in tsA201 cells and with native alpha4 AChRs isolated from brain. Coexpression of VILIP-1 with recombinant alpha4beta2 AChRs up-regulated their surface expression levels approximately 2-fold and increased their agonist sensitivity to acetylcholine approximately 3-fold. The modulation of the recombinant alpha4beta2 AChRs by VILIP-1 was attenuated in VILIP-1 mutants that lacked the ability to be myristoylated or to bind calcium. Collectively, these results suggest that VILIP-1 represents a novel modulator of alpha4beta2 AChRs that increases their surface expression levels and agonist sensitivity in response to changes in the intracellular levels of calcium.
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Affiliation(s)
- Lin Lin
- Neuroscience Center of Excellence, Louisiana, New Orleans 70112, USA
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7
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Lin L, Braunewell KH, Gundelfinger ED, Anand R. Functional analysis of calcium-binding EF-hand motifs of visinin-like protein-1. Biochem Biophys Res Commun 2002; 296:827-32. [PMID: 12200122 DOI: 10.1016/s0006-291x(02)00943-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Visinin-like protein-1 (VILIP-1), a myristoylated calcium sensor protein with three EF-hand motifs, modulates adenylyl cyclase activity. It translocates to membranes when a postulated "calcium-myristoyl switch" is triggered by calcium-binding to expose its sequestered myristoyl moiety. We investigated the contributions of the EF-hand motifs to the translocation of VILIP-1 to membranes and to the modulation of adenylyl cyclase activity. Mutation of residues crucial for binding calcium within each one of the EF-hand motifs indicated that they all contributed to binding calcium. Simultaneous mutations of all of the three EF-hand motifs completely abolished VILIP-1's ability to bind calcium, attenuated but did not eliminate its modulation of adenylyl cyclase activity, and abolished its calcium-dependence for association with cellular membranes. These results show that the calcium-binding EF-hand motifs of VILIP-1 do not have an essential role in modulating adenylyl cyclase activity but instead have a structural role in activating the "calcium-myristoyl switch" of VILIP-1.
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Affiliation(s)
- Lin Lin
- Neuroscience Center of Excellence, 2020 Gravier Street, Suite D, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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8
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Loring JF, Wen X, Lee JM, Seilhamer J, Somogyi R. A gene expression profile of Alzheimer's disease. DNA Cell Biol 2001; 20:683-95. [PMID: 11788046 DOI: 10.1089/10445490152717541] [Citation(s) in RCA: 226] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Postmortem analysis of brains of patients with Alzheimer's disease (AD) has led to diverse theories about the causes of the pathology, suggesting that this complex disease involves multiple physiological changes. In an effort to better understand the variety and integration of these changes, we generated a gene expression profile for AD brain. Comparing affected and unaffected brain regions in nine controls and six AD cases, we showed that 118 of the 7050 sequences on a broadly representative cDNA microarray were differentially expressed in the amygdala and cingulate cortex, two regions affected early in the disease. The identity of these genes suggests the most prominent upregulated physiological correlates of pathology involve chronic inflammation, cell adhesion, cell proliferation, and protein synthesis (31 upregulated genes). Conversely, downregulated correlates of pathology involve signal transduction, energy metabolism, stress response, synaptic vesicle synthesis and function, calcium binding, and cytoskeleton (87 downregulated genes). The results support several separate theories of the causes of AD pathology, as well as add to the list of genes associated with AD. In addition, approximately 10 genes of unknown function were found to correlate with the pathology.
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Affiliation(s)
- J F Loring
- Department of Life Sciences, Incyte Genomics, Inc., Palo Alto, California 94304, USA.
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9
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Spilker C, Richter K, Smalla KH, Manahan-Vaughan D, Gundelfinger ED, Braunewell KH. The neuronal EF-hand calcium-binding protein visinin-like protein-3 is expressed in cerebellar Purkinje cells and shows a calcium-dependent membrane association. Neuroscience 2000; 96:121-9. [PMID: 10683417 DOI: 10.1016/s0306-4522(99)00536-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Visinin-like protein-3 is a member of the family of intracellular neuronal calcium sensors belonging to the superfamily of EF-hand proteins. Members of this family are involved in the calcium-dependent regulation of signal transduction cascades. To gain insights into the characteristics of visinin-like protein-3, we have generated specific antibodies against visinin-like protein-3 and determined the developmental and tissue distribution of the protein and its exact cellular and subcellular localization. Expression of visinin-like protein-3 protein appeared late in development mainly in the cerebellum. It is strongly expressed in cerebellar Purkinje cells. The protein expression results were further confirmed by in situ hybridization and compared with hippocalcin messenger RNA localization. Native cerebellar visinin-like protein-3 was shown to bind calcium and to associate in a calcium-dependent manner with membrane fractions during subcellular fractionation. Recombinant wild-type visinin-like protein-3 was shown to be N-terminally myristoylated in transfected cells. The membrane association was strongly reduced for the non-myristoylated mutant of visinin-like protein-3 in transfected cells. These results suggest that visinin-like protein-3, which is mainly expressed in Purkinje cells in vivo, shows a calcium-dependent association with cell membranes which is mediated by a calcium-myristoyl switch.
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Affiliation(s)
- C Spilker
- Leibniz Institute for Neurobiology, P.O. Box 1860, D-39008, Magdeburg, Germany
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Kobayashi M, Sakai E, Furuta Y, Takamatsu K. Isolation of two human cDNAs, HLP3 and HLP4, homologous to the neuron-specific calcium-binding protein genes. DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 1999; 9:171-6. [PMID: 10520747 DOI: 10.3109/10425179809072192] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We have cloned and sequenced two types of human cDNA, HLP3 and HLP4, encoding a protein of 191 amino acid residues with four EF-hand calcium-binding motifs. The HLP3 and HLP4 proteins are homologous to the neuron-specific calcium-binding proteins and are likely human counterparts of the neural visinin-like protein(NVP) 1 and NVP2 identified in the rat brain (Kajimoto et al. 1993), displaying 98% and 99% amino acid identities with these sequences, respectively. The human HLP3 and 4 mRNAs are detected only in the brain and found at high amount in the cerebral cortex and cerebellum by Northern blot analysis.
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Affiliation(s)
- M Kobayashi
- Department of Physiology, Toho University School of Medicine, Tokyo, Japan
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Bogdanov YD, Balaban PM, Poteryaev DA, Zakharov IS, Belyavsky AV. Putative neuropeptides and an EF-hand motif region are encoded by a novel gene expressed in the four giant interneurons of the terrestrial snail. Neuroscience 1998; 85:637-47. [PMID: 9622259 DOI: 10.1016/s0306-4522(97)00561-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nine giant interneurons located in the pleural and parietal ganglia of the terrestrial snail Helix lucorum L. were reported to be a key element in the network controlling withdrawal behaviour of the animal. Using a combination of complementary DNA subtraction cloning and differential screening approaches we have isolated a novel gene named HCS2 which is expressed predominantly in a subset of these interneurons. The predicted amino acid sequence of the HCS2 protein contains at the N-terminus a hydrophobic leader sequence and four putative neuropeptides, and at the C-terminus a perfect match to the consensus motif of the EF-hand family of the Ca2+-binding proteins. All four predicted neuropeptides bear a C-terminal signature sequence Tyr-Pro-Arg-X (where X is Ile, Leu, Val or Pro), and three of them are likely to be amidated. Physiological action of three synthetic peptides corresponding to the predicted mature HCS2 peptides mimics fairly well the described action of parietal interneurons on follower motoneurons controlling pneumostome closure. In situ hybridization experiments demonstrated that the HCS2 gene is selectively expressed in the four parietal giant interneurons, as well as in several small unidentified neurons. The onset of the HCS2 transcription during embryogenesis coincides temporally with the time-point when the first withdrawal responses of the embryo to tactile stimulation appear. We propose that the HCS2 gene encodes a hybrid precursor protein whose processed products act as neuromodulators or neurotransmitters mediating the withdrawal reactions of the snail, and in addition may participate in the calcium regulatory pathways or calcium homeostasis in command neurons.
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Affiliation(s)
- Y D Bogdanov
- Engelhardt Institute of Molecular Biology, Moscow, Russia
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12
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Raju RV, Magnuson BA, Sharma RK. Mammalian myristoyl CoA: protein N-myristoyltransferase. Mol Cell Biochem 1995; 149-150:191-202. [PMID: 8569729 DOI: 10.1007/bf01076577] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Myristoyl CoA:Protein N-myristoyltransferase (NMT) is the enzyme which catalyses the covalent transfer of myristate from myristoyl CoA to the amino-terminal glycine residue of protein substrates. Although NMT is ubiquitous in eukaryotic cells, the enzyme levels and cellular distribution vary among tissues. In this article, we describe the properties of mammalian NMT(s) with reference to subcellular distribution, molecular weights, substrate specificity and the possible involvement of NMT in pathological processes. The cytosolic fraction of bovine brain contains majority of NMT activity. In contrast, rabbit colon and rat liver NMT activity was predominantly particulate. Regional differences in NMT activity have been observed in both rabbit intestine and bovine brain. Results from our laboratory along with the existing knowledge, provide evidence for the existence of tissue specific isozymes of NMT.
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Affiliation(s)
- R V Raju
- Department of Pathology, College of Medicine, Royal University Hospital, University of Saskatchewan, Saskatoon, Canada
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13
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Kawamura S. Photoreceptor light-adaptation mediated by S-modulin, a member of a possible regulatory protein family of protein phosphorylation in signal transduction. Neurosci Res 1994; 20:293-8. [PMID: 7870382 DOI: 10.1016/0168-0102(94)90050-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In vertebrate retinal photoreceptors, cytoplasmic [Ca2+] decreases upon exposure to light. A Ca(2+)-binding protein, S-modulin, detects this [Ca2+] decrease and reduces the light-sensitivity of the cell to induce light-adaptation. The reduction of the sensitivity is attained by disinhibition or facilitation of rhodopsin phosphorylation, a quenching mechanism of light-activated rhodopsin. S-modulin-like proteins are found in the brain as well. Several of these proteins show similar S-modulin effects, suggesting that these proteins also participate in the regulation of protein phosphorylation in the signal transduction in their host cells.
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Affiliation(s)
- S Kawamura
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
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