The Experts below are selected from a list of 1067016 Experts worldwide ranked by ideXlab platform
Ke Dong - One of the best experts on this subject based on the ideXlab platform.
-
DSC1 channel dependent developmental regulation of pyrethroid susceptibility in drosophila melanogaster
Pesticide Biochemistry and Physiology, 2018Co-Authors: Xueting Chen, Yuanyuan Wang, Ke DongAbstract:Abstract Pyrethroid insecticides modify the gating of voltage-gated sodium channels, thus disrupting the function of the nervous system. In Drosophila melanogaster, para encodes a functional sodium channel. Drosophila Sodium Channel 1 (DSC1), although considered as a putative sodium channel gene for decades due to its high sequence similarity with sodium channels, encodes a voltage-gated cation channel with high permeability to Ca2+. Previous study showed that knockout of the DSC1 gene (DSC1−/−) caused Drosophila adults to be more susceptible to pyrethroids and the adult giant fiber (GF) neural circuit were more susceptible to pyrethroids. Considering distinct expression of DSC1 transcripts in adults and larvae, we examined the role of DSC1 channels in regulating pyrethroid susceptibility in Drosophila larvae. We conducted insecticide bioassays and examined the susceptibility of the larval neuromuscular junction (NMJ) to pyrethroids using w1118, an insecticide-susceptible line, DSC1−/−, parats1 (a pyrethroid-resistant line carrying a mutation in para) and a double mutation line parats1; DSC1−/−. We found that, like the adult GF system, the NMJ of DSC1−/− flies is more susceptible to pyrethroids than that of w1118 with the pyrethroid susceptibility ranked as DSC1−/− > w1118 > parats1; DSC1−/− > parats1. However, DSC1−/− larvae were about two-fold more resistant to pyrethroids than w1118 larvae, and the pyrethroid susceptibility of larvae ranked as w1118 > DSC1−/− > parats1; DSC1−/− > parats1. These results reveal common and distinct roles of DSC1 channels in regulating the action of pyrethroids in adults and larvae of D. melanogaster.
-
distinct roles of the dmnav and DSC1 channels in the action of ddt and pyrethroids
Neurotoxicology, 2015Co-Authors: Frank D. Rinkevich, Josh Tolinski, Atsushi Ueda, Boris S Zhorov, Ke DongAbstract:Voltage-gated sodium channels (Nav channels) are critical for electrical signaling in the nervous system and are the primary targets of the insecticides DDT and pyrethroids. In Drosophila melanogaster, besides the canonical Nav channel, Para (also called DmNav), there is a sodium channel-like cation channel called DSC1 (Drosophila sodium channel 1). Temperature-sensitive paralytic mutations in DmNav (para(ts)) confer resistance to DDT and pyrethroids, whereas DSC1 knockout flies exhibit enhanced sensitivity to pyrethroids. To further define the roles and interaction of DmNav and DSC1 channels in DDT and pyrethroid neurotoxicology, we generated a DmNav/DSC1 double mutant line by introducing a para(ts1) allele (carrying the I265N mutation) into a DSC1 knockout line. We confirmed that the I265N mutation reduced the sensitivity to two pyrethroids, permethrin and deltamethrin of a DmNav variant expressed in Xenopus oocytes. Computer modeling predicts that the I265N mutation confers pyrethroid resistance by allosterically altering the second pyrethroid receptor site on the DmNav channel. Furthermore, we found that I265N-mediated pyrethroid resistance in para(ts1) mutant flies was almost completely abolished in para(ts1);DSC1(-/-) double mutant flies. Unexpectedly, however, the DSC1 knockout flies were less sensitive to DDT, compared to the control flies (w(1118A)), and the para(ts1);DSC1(-/-) double mutant flies were even more resistant to DDT compared to the DSC1 knockout or para(ts1) mutant. Our findings revealed distinct roles of the DmNav and DSC1 channels in the neurotoxicology of DDT vs. pyrethroids and implicate the exciting possibility of using DSC1 channel blockers or modifiers in the management of pyrethroid resistance.
-
The Drosophila Sodium Channel 1 (DSC1): The founding member of a new family of voltage-gated cation channels
Pesticide biochemistry and physiology, 2014Co-Authors: Ke Dong, Frank D. Rinkevich, Lingxin WangAbstract:It has been nearly three decades since the identification of the Drosophila Sodium Channel 1 (DSC1) gene from Drosophila melanogaster. The orthologs of the DSC1 gene have now been identified in other insect species including BSC1 from Blattella germanica. Functional analyses of DSC1/BSC1 channels in Xenopus oocytes reveal that DSC1 and BSC1 encode voltage-gated cation channels that are more permeable to Ca(2+) than to Na(+). Genetic and electrophysiological analyses show that knockout of the DSC1 gene in D. melanogaster causes behavioral and neurological modifications. In this review, we summarize major findings from recent studies and highlight a unique role of the DSC1 channel, distinct from that of the sodium channel, in regulating membrane excitability and modulating toxicity of pyrethroid insecticides.
-
role of the DSC1 channel in regulating neuronal excitability in drosophila melanogaster extending nervous system stability under stress
PLOS Genetics, 2013Co-Authors: Tianxiang Zhang, Lingxin Wang, Zhiqi Liu, Zhe Wang, Ningguang Luo, Lan Jiang, Ke DongAbstract:Voltage-gated ion channels are essential for electrical signaling in neurons and other excitable cells. Among them, voltage-gated sodium and calcium channels are four-domain proteins, and ion selectivity is strongly influenced by a ring of amino acids in the pore regions of these channels. Sodium channels contain a DEKA motif (i.e., amino acids D, E, K, and A at the pore positions of domains I, II, III, and IV, respectively), whereas voltage-gated calcium channels contain an EEEE motif (i.e., acidic residues, E, at all four positions). Recently, a novel family of ion channel proteins that contain an intermediate DEEA motif has been found in a variety of invertebrate species. However, the physiological role of this new family of ion channels in animal biology remains elusive. DSC1 in Drosophila melanogaster is a prototype of this new family of ion channels. In this study, we generated two DSC1 knockout lines using ends-out gene targeting via homologous recombination. DSC1 mutant flies exhibited impaired olfaction and a distinct jumpy phenotype that is intensified by heat shock and starvation. Electrophysiological analysis of the giant fiber system (GFS), a well-defined central neural circuit, revealed that DSC1 mutants are altered in the activities of the GFS, including the ability of the GFS to follow repetitive stimulation (i.e., following ability) and response to heat shock, starvation, and pyrethroid insecticides. These results reveal an important role of the DSC1 channel in modulating the stability of neural circuits, particularly under environmental stresses, likely by maintaining the sustainability of synaptic transmission.
-
molecular characterization of DSC1 orthologs in invertebrate species
Insect Biochemistry and Molecular Biology, 2012Co-Authors: Ying Jun Cui, Ke Dong, Chuanxi ZhangAbstract:DSC1 and BSC1 are two founding members of a novel family of invertebrate voltage-gated cation channels with close structural and evolutionary relationships to voltage-gated sodium and calcium channels. In this study, we searched the published genome sequences for DSC1 orthologs. DSC1 orthologs were found in all 48 insect species, and in other invertebrate species belonging to phyla Mollusca, Cnidaria, Hemichordata and Echinodermata. However, DSC1 orthologs were not found in four arachnid species, Ixodes scapularis, Rhipicephalus microplus, Tetranychus urticae and Varroa destructor, two species in Annelida or any vertebrate species. We then cloned and sequenced NlSC1 and BmSC1 full-length cDNAs from the brown planthopper (Nilaparvata lugens) and the silkworm (Bombyx mori), respectively. NlSC1 and BmSC1 share about 50% identity with DSC1, and the expression of NlSC1 and BmSC1 transcripts was most abundant in the head and antenna in adults. All DSC1 orthologs contain a unique and conserved DEEA motif, instead of the EEEE or EEDD motif in classical calcium channels or the DEKA motif in sodium channels. Phylogenetic analyses revealed that DSC1 and its orthologs form a separate group distinct from the classical voltage-gated sodium and calcium channels and constitute a unique family of cation channels. The DSC1/BSC1-family channels could be potential targets of new and safe insecticides for pest control.
Judy Wai Ping Yam - One of the best experts on this subject based on the ideXlab platform.
-
abstract 2141 camp pka signaling enhances activity of deleted in liver cancer 1 dlc1 tumor suppressor in suppressing liver cancer tumorigenesis
Cancer Research, 2012Co-Authors: Lo-kong Chan, Karen Man-fong Sze, Edith Yuk Ting Tse, Yin-shan Yeung, Judy Wai Ping YamAbstract:Deleted in Liver Cancer 1 (DLC1) which encodes a RhoGTPase-activating protein (RhoGAP) is a tumor suppressor frequently inactivated in a wide spectrum of human cancers. The RhoGAP activity has been shown to play a predominant role in the biological activities of DLC1. It has been shown that cells with silenced DLC1 exhibit increased active RhoA level. This finding provides evidence about the activation of RhoA as the consequence of deregulated DLC1 and points to the importance of RhoGAP activity in the biological activity of DLC1. In this regard, it is important to comprehend how RhoGAP activity of DLC1 is related. Here, we show that DLC1 was robustly phosphorylated by cyclic AMP (cAMP)/Protein kinase A (PKA) signaling in cells. Phosphorylation of DLC1 was enhanced by forskolin, a known activator of PKA while suppressed when H-89, an inhibitor of PKA was added. Direct phosphorylation of DLC1 by PKA was further confirmed by the in vitro kinase assay. Using specific phospho-DLC1 antibodies, PKA was shown to phosphorylate DLC1 at S431 and S549. Functional assays demonstrate that phosphorylation at S549 plays a critical role in provoking the inhibitory activity of DLC1 in suppressing growth and motility of Ras-transduced p53 null mouse hepatoblasts. When compared with the stable clone of wild-type DLC1, stable clone of DLC1 phosphomimetic mutant, S549D, displayed a largely reduced growth of subcutaneous and orthotopic liver implanted tumors and an enhanced apoptosis. The migration and invasion rates of S549D cells were also significantly inhibited. Furthermore, S549D expression abolished stress fiber formation but failed to alter filopodia protrusions. These functional effects exerted by S549D were ascribed to the enhanced RhoGAP activity against RhoA. To further investigate the mechanism through which the RhoGAP activity is enhanced, we found that DLC1 dimerized upon S549 phosphorylation. Our findings have revealed for the first time about the regulation of RhoGAP activity of DLC1 via dimerization. Our study suggests a molecular link between PKA and DLC1/Rho pathways and underscores the importance of S549 phosphorylation in the regulation of RhoGAP activity of DLC1. (This study was funded by the Small Project Funding Program, The University of Hong Kong 200907176125) Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2141. doi:1538-7445.AM2012-2141
-
deleted in liver cancer 1 dlc1 negatively regulates rho rock mlc pathway in hepatocellular carcinoma
PLOS ONE, 2008Co-Authors: Carmen Chak-lui Wong, Yickpang Ching, Chunming Wong, Lo-kong Chan, Judy Wai Ping YamAbstract:Aims Deleted in liver cancer 1 (DLC1), a member of RhoGTPase activating protein (GAP) family, is known to have suppressive activities in tumorigenicity and cancer metastasis. However, the underlying molecular mechanisms of how DLC1 suppresses cell motility have not been fully elucidated. Rho-kinase (ROCK) is an immediate down-stream effector of RhoA in mediating cellular cytoskeletal events and cell motility. In the present study, we aimed to investigate the effects of DLC1 on Rho/ROCK signaling pathway in hepatocellular carcinoma (HCC). Methodology/Principal Findings We demonstrated that DLC1 negatively regulated ROCK-dependent actomyosin contractility. From immumofluorescence study, we found that ectopic expression of DLC1 abrogated Rho/ROCK-mediated cytoskeletal reorganization including formation of stress fibers and focal adhesions. It also downregulated cortical phosphorylation of myosin light chain 2 (MLC2). These inhibitory events by DLC1 were RhoGAP-dependent, as RhoGAP-deficient mutant of DLC1 (DLC1 K714E) abolished these inhibitory events. In addition, from western study, DLC1 inhibited ROCK-related myosin light chain phosphatase targeting unit 1 (MYPT1) phosphorylation at Threonine 853. By examining cell morphology under microscope, we found that ectopic expression of dominant-active ROCK released cells from DLC1-induced cytoskeletal collapse and cell shrinkage. Conclusion Our data suggest that DLC1 negatively regulates Rho/ROCK/MLC2. This implicates a ROCK-mediated pathway of DLC1 in suppressing metastasis of HCC cells and enriches our understanding in the molecular mechanisms involved in the progression of hepatocellular carcinoma.
-
rho gtpase activating protein deleted in liver cancer suppresses cell proliferation and invasion in hepatocellular carcinoma
Cancer Research, 2005Co-Authors: Chunming Wong, Yickpang Ching, Judy Wai Ping Yam, Taion Yau, Thomas Hoyin Leung, Dongyan JinAbstract:Deleted in liver cancer (DLC1) is a candidate tumor suppressor gene recently isolated from human hepatocellular carcinoma. Structurally, DLC1 protein contains a conserved GTPase-activating protein for Rho family protein (RhoGAP) domain, which has been thought to regulate the activity of Rho family proteins. Previous studies indicated that DLC1 was frequently inactivated in cancer cells. In the present study, we aimed to characterize the tumor suppressor roles of DLC1 in hepatocellular carcinoma. We showed that DLC1 significantly inhibited cell proliferation, anchorage-independent growth, and in vivo tumorigenicity when stably expressed in hepatocellular carcinoma cells. Moreover, DLC1 expression greatly reduced the motility and invasiveness of hepatocellular carcinoma cells. With RhoGAP-deficient DLC1 mutant (DLC1-K714E), we showed that the RhoGAP activity was essential for DLC1-mediated tumor suppressor function. Furthermore, the 292– to 648–amino acid region and the steroidogenic acute regulatory related lipid transfer domain played an auxiliary role to RhoGAP and tumor suppressor function of DLC1. Taken together, our findings showed that DLC1 functions as a tumor suppressor in hepatocellular carcinoma and provide the first evidence to support the hypothesis that DLC1 suppresses cancer cell growth by negatively regulating the activity of Rho proteins.
Li Feng - One of the best experts on this subject based on the ideXlab platform.
-
disc1 regulates the proliferation and migration of mouse neural stem progenitor cells through pax5 sox2 dll1 and neurog2
Frontiers in Cellular Neuroscience, 2017Co-Authors: Weiting Tang, Zhaohui Luo, Yi Shu, Zongwei Yue, Bo Xiao, Li FengAbstract:Background: Disrupted-in-schizophrenia 1 (DISC1) regulates neurogenesis and is a genetic risk factor for major psychiatric disorders. However, how DISC1 dysfunction affects neurogenesis and cell cycle progression at the molecular level is still unknown. Here, we investigated the role of DISC1 in regulating proliferation, migration, cell cycle progression, and apoptosis in mouse neural stem/progenitor cells (MNSPCs) in vitro. Methods: MNSPCs were isolated and cultured from mouse fetal hippocampi. Retroviral vectors or siRNAs were used to manipulate DISC1 expression in MNSPCs. Proliferation, migration, cell cycle progression, and apoptosis of altered MNSPCs were analyzed in cell proliferation assays (MTS), transwell system, and flow cytometry. A neurogenesis specific PCR array was used to identify genes downstream of DISC1, and functional analysis was performed through transfection of expression plasmids and siRNAs. Results: Loss of DISC1 reduced proliferation and migration of MNSPCs, while an increase in DISC1 led to increased proliferation and migration. Meanwhile, an increase in the proportion of cells in G0/G1 phase was concomitant with reduced levels of DISC1, but significant changes were not observed in the number MNSPCs undergoing apoptosis. Pax5, Sox2, Dll1 and Neurog2 emerged as candidate molecules downstream of DISC1, and rescue experiments demonstrated that increased or decreased expression of either molecule regulated proliferation and migration in DISC1-altered MNSPCs. Conclusions: These results suggest that Pax5, Sox2, Dll1, and Neurog2 mediate DISC1 activity in MNSPC proliferation and migration.
-
DISC1 Regulates the Proliferation and Migration of Mouse Neural Stem/Progenitor Cells through Pax5, Sox2, Dll1 and Neurog2
Frontiers Media S.A., 2017Co-Authors: Weiting Tang, Zhaohui Luo, Yi Shu, Zongwei Yue, Bo Xiao, Li FengAbstract:Background: Disrupted-in-schizophrenia 1 (DISC1) regulates neurogenesis and is a genetic risk factor for major psychiatric disorders. However, how DISC1 dysfunction affects neurogenesis and cell cycle progression at the molecular level is still unknown. Here, we investigated the role of DISC1 in regulating proliferation, migration, cell cycle progression and apoptosis in mouse neural stem/progenitor cells (MNSPCs) in vitro.Methods: MNSPCs were isolated and cultured from mouse fetal hippocampi. Retroviral vectors or siRNAs were used to manipulate DISC1 expression in MNSPCs. Proliferation, migration, cell cycle progression and apoptosis of altered MNSPCs were analyzed in cell proliferation assays (MTS), transwell system and flow cytometry. A neurogenesis specific polymerase chain reaction (PCR) array was used to identify genes downstream of DISC1, and functional analysis was performed through transfection of expression plasmids and siRNAs.Results: Loss of DISC1 reduced proliferation and migration of MNSPCs, while an increase in DISC1 led to increased proliferation and migration. Meanwhile, an increase in the proportion of cells in G0/G1 phase was concomitant with reduced levels of DISC1, but significant changes were not observed in the number MNSPCs undergoing apoptosis. Paired box gene 5 (Pax5), sex determining region Y-box 2 (Sox2), delta-like1 (Dll1) and Neurogenin2 (Neurog2) emerged as candidate molecules downstream of DISC1, and rescue experiments demonstrated that increased or decreased expression of either molecule regulated proliferation and migration in DISC1-altered MNSPCs.Conclusion: These results suggest that Pax5, Sox2, Dll1 and Neurog2 mediate DISC1 activity in MNSPC proliferation and migration
A Goverse - One of the best experts on this subject based on the ideXlab platform.
-
the tir nb lrr pair DSC1 and wrky19 contributes to basal immunity of arabidopsis to the root knot nematode meloidogyne incognita
BMC Plant Biology, 2020Co-Authors: S Warmerdam, Mark G Sterken, Octavina C A Sukarta, Casper Van Schaik, Marian Oortwijn, Jose L Lozanotorres, Jaap Bakker, Geert Smant, A GoverseAbstract:Root-knot nematodes transform vascular host cells into permanent feeding structures to withdraw nutrients from the host plant. Ecotypes of Arabidopsis thaliana can display large quantitative variation in susceptibility to the root-knot nematode Meloidogyne incognita, which is thought to be independent of dominant major resistance genes. However, in an earlier genome-wide association study of the interaction between Arabidopsis and M. incognita we identified a quantitative trait locus harboring homologs of dominant resistance genes but with minor effect on susceptibility to the M. incognita population tested. Here, we report on the characterization of two of these genes encoding the TIR-NB-LRR immune receptor DSC1 (DOMINANT SUPPRESSOR OF Camta 3 NUMBER 1) and the TIR-NB-LRR-WRKY-MAPx protein WRKY19 in nematode-infected Arabidopsis roots. Nematode infection studies and whole transcriptome analyses using the Arabidopsis mutants showed that DSC1 and WRKY19 co-regulate susceptibility of Arabidopsis to M. incognita. Given the head-to-head orientation of DSC1 and WRKY19 in the Arabidopsis genome our data suggests that both genes may function as a TIR-NB-LRR immune receptor pair. Unlike other TIR-NB-LRR pairs involved in dominant disease resistance in plants, DSC1 and WRKY19 most likely regulate basal levels of immunity to root-knot nematodes.
Ken Ishii - One of the best experts on this subject based on the ideXlab platform.
-
pemphigus vulgaris and foliaceus igg autoantibodies directly block heterophilic transinteraction between desmoglein and desmocollin
Journal of Investigative Dermatology, 2020Co-Authors: Ken Ishii, John R Stanley, Masayuki Amagai, Kenji Yoshida, Jun Yamagami, Akira IshikoAbstract:Anti-desmoglein (Dsg) 1 and Dsg3 IgG autoantibodies in pemphigus foliaceus and pemphigus vulgaris cause blisters through loss of desmosomal adhesion. It is controversial whether blister formation is due to direct inhibition of Dsg, intracellular signaling events causing desmosome destabilization, or both. Recent studies show that heterophilic binding between Dsg and desmocollin (Dsc) is the fundamental adhesive unit of desmosomes. To eliminate cellular contributions to potential pathogenicity of pemphigus antibodies, bead assays coated with recombinant Dsg1, DSC1, Dsg3, or Dsc3 ectodomains were developed. A mixture of Dsg beads and Dsc beads formed large aggregates, confirming that the heterophilic binding is dominant. The pathogenic anti-Dsg1 and anti-Dsg3 mAbs, which bind the transadhesive interface, blocked the aggregation of Dsg1/DSC1 and Dsg3/Dsc3 beads, respectively, whereas nonpathogenic mAbs did not. All sera tested from eight patients with pemphigus foliaceus and eight patients with mucosal pemphigus vulgaris with active disease inhibited the adhesion of Dsg1/DSC1 and Dsg3/Dsc3 beads, respectively. When paired sera obtained from seven patients with pemphigus foliaceus and six patients with pemphigus vulgaris in active disease and remission were compared, the former inhibited aggregation better than the latter. These findings strongly suggest that steric hindrance of heterophilic transinteraction between Dsg and Dsc is important for disease pathology in both pemphigus foliaceus and pemphigus vulgaris.
-
Coordinated expression of desmoglein 1 and desmocollin 1 regulates intercellular adhesion.
Differentiation; research in biological diversity, 2004Co-Authors: Rachel L. Dusek, Ken Ishii, Linda J. Sheu, Lisa M. GodselAbstract:Desmoglein 1 (Dsg1) is a component of desmosomes present in the upper epidermis and can be targeted by autoimmune antibodies or bacterial toxins, resulting in skin blistering diseases. These defects in tissue integrity are believed to result from compromised desmosomal adhesion; yet, previous attempts to directly test the adhesive roles of desmosomal cadherins using normally non-adherent L cells have yielded mixed results. Here, two complementary approaches were used to better resolve the molecular determinants for Dsg1-mediated adhesion: (1) a tetracycline-inducible system was used to modulate the levels of Dsg1 expressed in L cell lines containing desmocollin 1 (DSC1) and plakoglobin (PG) and (2) a retroviral gene delivery system was used to introduce Dsg1 into normal human epidermal keratinocytes (NHEK). By increasing Dsg1 expression relative to DSC1 and PG, we were able to demonstrate that the ratio of Dsg1:DSC1 is a critical determinant of desmosomal adhesion in fibroblasts. The distribution of Dsg1 was organized at areas of cell–cell contact in the multicellular aggregates that formed in these suspension cultures. Similarly, the introduction of Dsg1 into NHEKs was capable of increasing the aggregation of single cell suspensions and further enhanced the adhesive strength of intact epithelial sheets. Endogenous DSC1 levels were also increased in NHEKs containing Dsg1, providing further support for the coordination of these two desmosomal cadherins in regulating adhesive structures. These Dsg1-mediated effects on intercellular adhesion were directly related to the presence of an intact extracellular domain as ETA, a toxin that specifically cleaves this desmosomal cadherin, inhibited adhesion in both fibroblasts and keratinocytes. Collectively, these observations demonstrate that Dsg1 promotes the formation of intercellular adhesion complexes and suggest that the relative level of Dsg and Dsc expressed at the cell surface regulates this adhesive process.
-
Assembly of desmosomal cadherins into desmosomes is isoform dependent
Journal of Investigative Dermatology, 2001Co-Authors: Ken Ishii, Leslie J Bannon, Suzanne M. Norvell, Evangeline V Amargo, Lauren T. PascoeAbstract:Desmosomes are intercellular adhesive junctions that exhibit cell- and differentiation-specific differences in their molecular composition. In complex epithelia, desmosomes contain multiple representatives of the desmosomal cadherin family, which includes three desmogleins and three desmocollins. Rules governing the assembly of desmosomal cadherin isoforms into desmosomes of different cell types are unknown. Here we compared the assembly properties of desmoglein 2 (Dsg2) and desmocollin 2 (Dsc2), which are widely expressed, with Dsg1 and DSC1, which are expressed in the differentiated layers of complex epithelia, by introducing myc-tagged forms into simple and squamous epithelial cells that do not express Dsg1 or DSC1. Dsc2.myc and Dsg2.myc assembled efficiently into desmosomes in every cell type in spite of significant shifts in the stoichiometric relationship between desmogleins and desmocollins. In contrast, DSC1a.myc, DSC1b.myc, and Dsg1.myc did not stably incorporate into desmosomes in any line. Coexpression of DSC1a.myc or DSC1b.myc and Dsg1.myc did not lead to their colocalization and failed to enhance incorporation of either cadherin into desmosomes. Dsg1.myc, but not DSC1a, DSC1b, disrupted desmosome assembly in a cell-type-specific manner, and disruption correlated with the recruitment of Dsg1.myc, but not DSC1a or DSC1b, into a Triton-insoluble pool. The plakoglobin:E-cadherin ratio decreased in Dsg1-expressing cells with disrupted desmosomes, but a decrease was also observed in a DSC1a line. Thus, a modest reduction of plakoglobin associated with E-cadherin is apparently not sufficient to disrupt desmosome assembly. Our results demonstrate that desmosome assembly tolerates large shifts in cadherin stoichiometry, but is sensitive to isoform-specific differences exhibited by desmogleins and desmocollins.
-
Human Desmocollin 1 (DSC1) Is an Autoantigen for the Subcorneal Pustular Dermatosis Type of IgA Pemphigus
Journal of Investigative Dermatology, 1997Co-Authors: Chie Kiyokawa, Minoru Miyasato, Martyn A.j. Chidgey, David R. Garrod, Koji Komori, Yasushi Kobayashi, Osamu Mori, Ken IshiiAbstract:IgA pemphigus showing IgA anti-keratinocyte cell surface autoantibodies is divided into subcorneal pustular dermatosis (SPD) and intraepidermal neutrophilic IgA dermatosis (IEN) types. We previously showed by immunoblotting that IgA from some IgA pemphigus patients reacted with bovine desmocollins (Dsc), but not human Dsc. To determine the antigen for IgA pemphigus, we focused on conformation-dependent epitopes of Dsc, because sera of patients with classical pemphigus recognize conformation-sensitive epitopes of desmogleins. We constructed mammalian expression vectors containing the entire coding sequences of human DSC1, Dsc2, and Dsc3 and transiently transfected them into COS7 cells by lipofection. Immunofluorescence of COS7 cells transfected with single human Dscs showed that IgA antibodies of all six SPD-type IgA pemphigus cases reacted with the surface of cells expressing DSC1, but not with cells expressing Dsc2 or Dsc3. In contrast, none of seven IEN-type IgA pemphigus cases reacted with cells transfected with any Dscs. These results convincingly indicate that human DSC1 is an autoantigen for SPD-type IgA pemphigus, suggesting the possibility of an important role for DSC1 in the pathogenesis of this disease. This study shows that a Dsc can be an autoimmune target in human skin disease.
