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Rod Domain (rod + domain)
Selected AbstractsKeratin 9 gene mutations in five Korean families with epidermolytic palmoplantar keratodermaEXPERIMENTAL DERMATOLOGY, Issue 6 2003Joo-Heung Lee Abstract:, Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant disease characterized clinically by localized palmoplantar thickening and histopathologically by granular degeneration of the epidermis. Recent molecular biological studies have revealed that EPPK is caused by mutations of the keratin 9 gene in sequences mainly encoding the highly conserved 1 A rod domain. Here we demonstrate a novel mutation of N160H (position 8 of the 1 A domain) and two other previously reported mutations, R162W and N160S, in five unrelated Korean families with EPPK. The three-dimensional structure of the 1 A domain of the related vimentin intermediate filament protein chain is now known. Based on its likely similarity to the keratin 9 chain, we predict that inappropriate amino acid substitutions in position 10 of 1 A will likely interfere with coiled-coil dimer stability, and those in position 8 will interfere with tetramer stability. Accordingly, these mutations compromise the structural integrity of the keratin intermediate filaments leading to the pathology of EPPK. [source] Actin-binding domain of mouse plectinFEBS JOURNAL, Issue 10 2004Crystal structure, binding to vimentin Plectin, a large and widely expressed cytolinker protein, is composed of several subdomains that harbor binding sites for a variety of different interaction partners. A canonical actin-binding domain (ABD) comprising two calponin homology domains (CH1 and CH2) is located in proximity to its amino terminus. However, the ABD of plectin is unique among actin-binding proteins as it is expressed in the form of distinct, plectin isoform-specific versions. We have determined the three-dimensional structure of two distinct crystalline forms of one of its ABD versions (pleABD/2,) from mouse, to a resolution of 1.95 and 2.0 Å. Comparison of pleABD/2, with the ABDs of fimbrin and utrophin revealed structural similarity between plectin and fimbrin, although the proteins share only low sequence identity. In fact, pleABD/2, has been found to have the same compact fold as the human plectin ABD and the fimbrin ABD, differing from the open conformation described for the ABDs of utrophin and dystrophin. Plectin harbors a specific binding site for intermediate filaments of various types within its carboxy-terminal R5 repeat domain. Our experiments revealed an additional vimentin-binding site of plectin, residing within the CH1 subdomain of its ABD. We show that vimentin binds to this site via the amino-terminal part of its rod domain. This additional amino-terminal intermediate filament protein binding site of plectin may have a function in intermediate filament dynamics and assembly, rather than in linking and stabilizing intermediate filament networks. [source] Are giant axons a pathological marker of charcot-marie-tooth neuropathy type 2E?JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2004T Cavallaro Background: According to electrophysiological and pathological criteria Charcot Marie Tooth (CMT) disease includes primary demyelinating forms (CMT1) and neuropathies with primary axonal loss (CMT2). In CMT1, genetic analysis provided some associations between characteristic lesions and different proteins. In CMT2, four genes were identified recently (CMT2A, B, D, E); the molecular diagnosis is complex and phenotypical hallmarks are lacking. Objectives: To describe the nerve biopsy in three pedigrees with CMT2E caused by mutations of the neurofilament-light chain gene (NF-L): two pedigrees from Campania sharing a Pro22Ser substitution in the head domain of protein and one pedigree from Apulia with a novel Leu268Prol substitution in the central rod domain. In all three pedigrees electrophysiology was consistent with a mixed, demyelinating and axonal neuropathy. Results: The three patients analysed revealed a primary axonopathy characterized by giant axonal swelling filled with densely packed neurofilaments and some atrophic axons. Conclusions: We propose that, in the diagnostic work up of CMT2, giant axons may orientate towards CMT2E. The pathological alterations detected correlate intuitively with an altered function of the neurofilaments which constitute the axonal cytoskeleton and are critical for radial growth and for axonal transport. [source] Absence of neuronal nitric oxide synthase (nNOS) as a pathological marker for the diagnosis of Becker muscular dystrophy with rod domain deletionsNEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 5 2004S. Torelli Immunohistochemistry using antibodies to dystrophin is the pathological basis for the diagnosis of Duchenne and Becker muscular dystrophy (DMD and BMD). While the sarcolemma of DMD muscle is negative, BMD muscle generally shows variable labelling because of the translation of a partially functional dystrophin that is localized to the sarcolemma. In rare cases, however, this labelling is equivocal and similar to that observed in controls making diagnosis difficult. We report here that in such instances immunolabelling with antibodies to the neuronal form of nitric oxide synthase (nNOS) can be useful in suspecting a dystrophinopathy with a mutation in the ,hot-spot' rod domain and help to direct molecular analysis. nNOS localizes to the sarcolemma of mature muscle fibres via several components of the dystrophin-associated protein complex (DAPC) including dystrophin but sarcolemmal nNOS is lost when dystrophin levels are very low or absent because of deletions in critical regions of the rod domain. We report three cases who presented with only mild or no muscle weakness but had elevated serum creatine kinase activity and dystrophin immunolabelling indistinguishable from normal, making a pathological diagnosis difficult. All three cases had a complete absence of sarcolemmal nNOS and were subsequently found to have an in-frame deletion in the common rod domain exons (in these cases 48, 45,51, 47,53) compatible with a BMD. In addition, we observed that nNOS appears to be developmentally regulated with the antibody used and was often absent from the sarcolemma of immature fibres. These findings demonstrate the value of including antibodies to nNOS in routine immunohistochemical studies and that absence of nNOS can be a more sensitive marker than up-regulation of utrophin for diagnosis of BMD. Immaturity of fibres, however, needs to be taken into account, especially in neonates. [source] Bullous Congenital Ichthyosiform Erythroderma: A Sporadic Case Produced by a New KRT10 Gene MutationPEDIATRIC DERMATOLOGY, Issue 4 2009ISABEL BETLLOCH M.D., Ph.D. We report the case of a girl with typical clinical and histopathologic findings of bullous congenital ichthyosiform erythroderma, who was found to have a new mutation in KRT10 gene, Glu445Lys at position 445, affecting the 2B region of the KRT10 protein, the end of the rod domain, where many other keratin mutations associated with hereditary skin disease have been reported. This new mutation contributes to add to the catalog of bullous congenital ichthyosiform erythroderma mutations known. [source] Dynamic association between ,-actinin and ,-integrin regulates contraction of canine tracheal smooth muscleTHE JOURNAL OF PHYSIOLOGY, Issue 3 2006Wenwu Zhang The adhesion junctions of smooth muscle cells may be dynamically regulated during smooth muscle contraction, and this dynamic regulation may be important for the development of active tension. In the present study, the role of ,-actinin during smooth muscle contraction was evaluated in tracheal smooth muscle tissues and freshly dissociated cells. Stimulation with acetylcholine (ACh) increased the localization of ,-actinin at the membrane of freshly dissociated smooth muscle cells, and increased the amount of ,1 integrin that coprecipitated with ,-actinin from muscle tissue homogenates. GFP-,-actinin fusion proteins were expressed in muscle tissues and visualized in live freshly dissociated cells. GFP-,-actinin translocated to the membrane within seconds of stimulation of the cells with ACh. Expression of the integrin-binding rod domain of ,-actinin in smooth muscle tissues depressed active contraction in response to ACh. Expression of the ,-actinin rod domain also inhibited the translocation of endogenous ,-actinin to the membrane, and inhibited the association of endogenous ,-actinin with ,1 -integrin in ,-actinin immunoprecipitates from tissue extracts. However, the expression of ,-actinin rod domain peptides did not inhibit increases in myosin light chain phosphorylation or actin polymerization in response to stimulation with ACh. Results suggest that contractile stimulation of smooth muscle causes the rapid recruitment of ,-actinin to ,-integrin complexes at the membrane, and that the recruitment of ,-actinin to integrin complexes is necessary for active tension development in smooth muscle. [source] Analysis of Dystrophin Gene Deletions Indicates that the Hinge III Region of the Protein Correlates with Disease SeverityANNALS OF HUMAN GENETICS, Issue 3 2005A. Carsana Summary We have investigated the frequency of deletions in the dystrophin gene in 108 unrelated Duchenne and Becker muscular dystrophy (DMD/BMD) patients from southern Italy (DMD, n. 47; BMD, n. 61) and identified 89 deletions. The de novo mutation rate (about 30%), and the preferentially maternal origin of deletional mutations, analysed in families in which the maternal grandparents were available or their haplotypes could be unequivocally reconstructed, are in agreement with data reported for other populations. The correlation between BMD phenotype and type of deletion suggests that, in the distal rod domain region, the deletion size may not be as crucial as the particular combination of missing exons. In fact, we provide immunohistochemical and clinical evidence that in-frame deletion of the hinge III region in the distal rod domain results in a milder phenotype as compared with shorter deletions that do not include the hinge III region. Our data obtained in BMD patients, by confirming inferences arising from minigene transfection experiments in mdx mice, represent an important contribution to gene therapy approaches. [source] Antiplectin autoantibodies in subepidermal blistering diseasesBRITISH JOURNAL OF DERMATOLOGY, Issue 4 2009J.J.A. Buijsrogge Summary Background, Hemidesmosomal proteins may become targets of autoimmunity in subepidermal blistering diseases. Well-known recognized autoantigens are the intracellular plaque protein BP230, the transmembrane BP180 and its shed ectodomain LAD-1. Objectives, To establish the prevalence of autoimmunity against plectin, another intracellular plaque protein, and to investigate its antigenic sites. Methods, Two hundred and eighty-two patients with subepidermal blistering diseases, investigated by routine immunoblot analysis for possible antiplectin antibodies, were included in the study. Epitope mapping was performed using recombinantly produced overlapping plectin domains from the actin-binding domain to the rod domain. The COOH-terminal region of plectin was not included in the study. Results, In 11 of 282 (3·9%) patients an immunoblot staining pattern identical to that of antiplectin monoclonal antibody HD121 was found. Affinity-purified antibodies bound back to normal human skin in a pattern typical for plectin, i.e. to the epidermal basement membrane zone as well as to keratinocytes in the epidermis, and to myocytes. No binding was seen to plectin-deficient skin of a patient with epidermolysis bullosa simplex with muscular dystrophy. Epitope mapping of the plectin molecule showed that the central coiled-coil rod domain is an immunodominant hotspot as 92% of the sera with antiplectin antibodies reacted with it. Most patients with antiplectin antibodies also had antibodies to other pemphigoid antigens. Conclusions, Plectin is a minor pemphigoid antigen with an immunodominant epitope located on the central rod domain. [source] Lethal autosomal recessive epidermolytic ichthyosis due to a novel donor splice-site mutation in KRT10BRITISH JOURNAL OF DERMATOLOGY, Issue 6 2010C. Covaciu Epidermolytic ichthyosis (EI; MIM 113800), previously named bullous congenital ichthyosiform erythroderma or epidermolytic hyperkeratosis, is a rare and clinically variable defect of cornification characterized by generalized erythema, erosions, scaling and easily breaking blisters that become less frequent later in life while hyperkeratosis increases.1 EI is caused by dominant mutations in either KRT1 or KRT10, encoding keratin 1 (K1) and keratin 10 (K10), respectively.1 Usually, mutations are missense substitutions into the highly conserved ,-helical rod domains of the proteins.2,3 However, three inbred pedigrees in which EI is transmitted as a recessive trait due to KRT10 null mutations have been described.4,6 [source] | |||||||||||||