scholarly journals Modelling protein functional domains in signal transduction using Maude

2003 ◽  
Vol 4 (3) ◽  
pp. 236-245 ◽  
Author(s):  
M. G. Sriram
Keyword(s):  
Signal Transduction ◽  
Functional Domains ◽  
Protein Functional Domains

MUNC13–4 Mutations in Patients with Hemophagocytic Lymphohistiocytosis Are Scattered over the Functional Domains of the Protein.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1249-1249
Author(s):  
Alessandra Santoro ◽  
Sonia Cannella ◽  
Giovanna Bossi ◽  
Federico Gallo ◽  
Antonino Trizzino ◽  
...  
Keyword(s):  
Hemophagocytic Lymphohistiocytosis ◽  
Stop Codon ◽  
Functional Domains ◽  
Functional Domain ◽  
Missense Mutations ◽  
Coding Region ◽  
Cycle Sequencing ◽  
Familial Form ◽  
Protein Functional Domains

Abstract Mutations of PRF1 and MUNC13–4 genes, involved with cellular cytotoxicity, are associated with the familial form of Hemophagocytic Lymphohistiocytosis (HLH) type 2 (FHL2) and 3 (FHL3). In all patients with HLH, in which PRF1 mutations had been excluded, we screened MUNC13–4 mutations. The 32 exons and their proximal flanking regions of MUNC13–4 gene were sequenced by “cycle sequencing” approach (BigDye Terminator, Applied Biosystems). Of 60 patients, 21 had MUNC13–4 mutations. 5 were reported mutations: 753+1G>T, 817C>T (R273X); 1389+1G>A; 1822del 12 bp (del V608-A611); 2346–9delGGAG (R782FsX12). Of 16 novel mutations 2 (2212C>T and 2650C>T) introduce a stop codon (at Q738 and Q884); 4 cause frameshift: 441delA (P147fsX14), 532delC (Q178fsX70), 3082delC (L1028fsX), and 3226insG (H1076fsX51). Of 8 missense mutations [175G>A (A59T), 419T>C (I140T), 610A>G (M204B), 1241G>T (R414L), 1847A>G (E616G), 2039G>C (R680P), 2570T>G (F857C), 2782C>T (R928C)], 6 fall within the protein functional domains; each of the 2 falling outside was associated with 2 additional pathogenic mutations. The remaining novel 1992+5 G>A and 2448insC −12 fall outside the coding region but are close enough to induce alternative splicing. We identified polymorphisms 279C>T and 3198A>G. The 2599A>G (K867E) transition was found in several unrelated families, including one homozygous parent. To assess its frequency we studied 50 consecutive newborns, of which 64% were heterozygous. To understand the effects of the mutations we analysed Munc13–4 protein expression from CTL and/or NK cells by western blot using an antibody raised against amino acids 1–262. Trace amounts of protein could be detected only in 5 patients. Analysis of granule polarisation in 2 patients with trace amounts of Munc13–4 protein showed many more docked granules visible than in controls, consistent with a block in granule secretion in these patients. Median age at diagnosis of FHL3 was 6.5 months, but 8/21 (38%) patients were diagnosed when older than 5 years, with one young adult of 18 years. CNS disease was present in 10 patients; NK was markedly reduced or absent in all patients tested. MUNC13–4 mutations were found in 35% of our HLH patients non type-2. Mutations were almost entirely different from those reported so far and scattered over different exons, but in far most cases they fall within the protein functional domain. Since these patients may develop the disease during adolescence or even later on, not only pediatric but also as adults hematologists should include FHL-2 and 3 in the differential diagnosis of children and young adults with fever, cytopenia, splenomegaly and hypercytokinemia.

Ultrastructural aspects of olfactory signal transduction and its development

1994 ◽  
Vol 52 ◽  
pp. 142-143
Author(s):  
Bert Ph. M. Menco
Keyword(s):  
Signal Transduction ◽  
Olfactory Receptor ◽  
Receptor Cell ◽  
Freeze Substitution ◽  
Luminal Surface ◽  
Tissue Sections ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Olfactory Signal ◽  
Odor Molecule

Vertebrate olfactory receptor cells are specialized neurons that have numerous long tapering cilia. The distal parts of these cilia line the interface between the external odorous environment and the luminal surface of the olfactory epithelium. The length and number of these cilia results in a large surface area that presumably increases the chance that an odor molecule will meet a receptor cell. Advanced methods of cryoprepration and immuno-gold labeling were particularly useful to preserve the delicate ultrastructural and immunocytochemical features of olfactory cilia required for localization of molecules involved in olfactory signal-transduction. We subjected olfactory tissues to freeze-substitution in acetone (unfixed tissues) or methanol (fixed tissues) followed by low temperature embedding in Lowicryl K11M for that purpose. Tissue sections were immunoreacted with several antibodies against proteins that are presumably important in olfactory signal-transduction.

Signal-regulated oxidation of proteins via MICAL

2020 ◽  
Vol 48 (2) ◽  
pp. 613-620
Author(s):  
Clara Ortegón Salas ◽  
Katharina Schneider ◽  
Christopher Horst Lillig ◽  
Manuela Gellert
Keyword(s):  
Signal Transduction ◽  
Hydrogen Peroxide ◽  
Cell Death ◽  
Redox Regulation ◽  
Signal Transduction Pathways ◽  
Cellular Functions ◽  
Intracellular Signals ◽  
Amino Acid Side Chains ◽  
Specific Receptors ◽  
Sulfur Containing

Processing of and responding to various signals is an essential cellular function that influences survival, homeostasis, development, and cell death. Extra- or intracellular signals are perceived via specific receptors and transduced in a particular signalling pathway that results in a precise response. Reversible post-translational redox modifications of cysteinyl and methionyl residues have been characterised in countless signal transduction pathways. Due to the low reactivity of most sulfur-containing amino acid side chains with hydrogen peroxide, for instance, and also to ensure specificity, redox signalling requires catalysis, just like phosphorylation signalling requires kinases and phosphatases. While reducing enzymes of both cysteinyl- and methionyl-derivates have been characterised in great detail before, the discovery and characterisation of MICAL proteins evinced the first examples of specific oxidases in signal transduction. This article provides an overview of the functions of MICAL proteins in the redox regulation of cellular functions.

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