Search results for "MUTATION"
showing 10 items of 2830 documents
Mutation of the important Tyr-33 residue of chicken avidin: functional and structural consequences
2002
The strong interaction between avidin and biotin is so tight (dissociation constant 10-15M) that conditions usually sufficient for protein denaturing fail to dislodge biotin from the avidin—biotin complex. This kind of irreversible binding hinders the use of avidin in applications such as affinity purification or protein immobilization. To address this concern, we have constructed a series of mutants of the strategically positioned Tyr-33 in order to study the role of this residue in biotin binding, and to create avidin variants with more reversible ligand-binding properties. Unexpectedly, an avidin mutant in which Tyr-33 was replaced with phenylalanine (Avm-Y33F) displayed similar biotin-b…
Phosphorylation of CalDAG-GEFI by protein kinase A prevents Rap1b activation.
2013
Summary Background Signaling via protein kinase A (PKA) and protein kinase G (PKG) is critical for maintaining platelets in the resting state. Both kinases down-regulate the activity of the small GTPase Rap1b, a critical signaling switch for integrin activation and platelet aggregation. However, the mechanism of Rap1b regulation by PKA and PKG is largely unknown. Objective To identify the PKA phosphorylation sites in calcium and diacylglycerol-regulated guanine nucleotide exchange factor I (CalDAG-GEFI), the main GEF for Rap1b in platelets, and the effect of CalDAG-GEFI phosphorylation in Rap1b activation. Methods The phosphorylation sites in CalDAG-GEFI were identified by radio-active phos…
First case in Italy of acquired resistance to oseltamivir in an immunocompromised patient with influenza A/H1N1v infection
2010
A pandemic influenza A/H1N1v strain with the neuraminidase H274Y mutation was detected in nasal secretions of a 2-year-old leukemic patient with influenza-like illness after 18 days of treatment with oseltamivir. At baseline, no drug-resistant virus was found, while 4 days after treatment initiation a mix- ture of wild-type and mutated virus was detected. After treatment interruption, the wild type influenza virus re-emerged and became prevalent in nasal secretions after a few days, suggesting the lower fitness of the mutated virus strain. The patient slowly improved concurrently with a decrease in virus load, which resulted negative 42 days after diagnosis. No other drug-resistant influenz…
Phenotype/Genotype Relationship in Left Ventricular Noncompaction: Ion Channel Gene Mutations Are Associated With Preserved Left Ventricular Systolic…
2021
International audience; Background: Few data exist concerning genotype-phenotype relationships in left ventricular noncompaction (LVNC).Methods and results: From a multicenter French Registry, we report the genetic and clinical spectrum of 95 patients with LVNC, and their genotype-phenotype relationship. Among the 95 LVNC, 45 had at least 1 mutation, including 14 cases of mutation in ion channel genes. In a complementary analysis including 16 additional patients with ion channel gene mutations, for a total of 30 patients with ion channel gene mutation, we found that those patients had higher median LV ejection fraction (60% vs 40%; P < .001) and more biventricular noncompaction (53.1% vs 18…
Phenotypic APC resistance as a marker of hypercoagulability in primitive cerebral lymphoma
2005
Thrombosis is the most frequent complication and the second cause of death in patients with malignant disease. Primary central nervous system non-Hodgkin's lymphoma represents a rare pathology. Resistance to APC is usually linked to a factor V (FV) gene mutation changing an Arg 506 to a Gln in the APC cleavage site.In our study, we aimed at investigating the presence of activated protein C resistance (APC-r) and other markers of hypercoagulability in 25 selected patients with a diagnosis of primitive cerebral lymphoma who had suffered from an ischemic episode of TIA and/or stroke.25 selected patients with a diagnosis of primitive cerebral lymphoma and 50 healthy subjects acted as control gr…
Genotype‐phenotype correlations in Brazilian patients with hereditary angioedema due to C1 inhibitor deficiency. [Carta]
2019
Cylindromatosis (Cyld) gene mutation in T cells promotes the development of an IL-9-dependent allergic phenotype in experimental asthma
2016
Cylindromatosis (CYLD) is a ubiquitously expressed deubiquitinating enzyme which removes activating ubiquitin residues from important signaling molecules of the NF-κB pathway. In CYLDex7/8 transgenic mice, a naturally occurring short isoform (sCYLD) is overexpressed in the absence of full length CYLD, leading to excessive NF-κB activity. Herein, we investigated the impact of the CYLDex7/8 mutation selectively in T cells on the development of experimental allergic airway disease induced by sensitization and challenge with ovalbumin. Compared with their wildtype littermates, mice bearing the T cell-specific mutation (CD4+CYLDex7/8) display stronger eosinophilia and mucus production in the lun…
Proliferative response of CD4+ T cells and hepatitis B virus clearance in chronic hepatitis with or without hepatitis B e-minus hepatitis B virus mut…
1995
To assess the significance of cell-mediated immunity, T cells were derived from the peripheral blood and liver tissue of hepatitis B virus (HBV)-infected patients and controls. The analysis of the 3H-thymidine-uptake in response to a panel of recombinant HBV antigens revealed that peripheral blood mononuclear cells (PBMC) of the 25 viremic patients with inflammatory active, chronic hepatitis B, 16 with wild-type and nine with HBe-minus HBV mutant infection, showed stronger proliferative responses to HBc and HBe antigens than 16 asymptomatic nonviremic HBsAg carriers with normal aminotransferase levels (HBc: SI 19.3 +/- 3.9 vs. 13.0 +/- 3.2 vs. 8.0 +/- 1.2; P.01 and HBe: SI 16.6 +/- 4.0 vs. …
Mutant MHC class II epitopes drive therapeutic immune responses to cancer
2015
Tumour-specific mutations are ideal targets for cancer immunotherapy as they lack expression in healthy tissues and can potentially be recognized as neo-antigens by the mature T-cell repertoire. Their systematic targeting by vaccine approaches, however, has been hampered by the fact that every patient's tumour possesses a unique set of mutations ('the mutanome') that must first be identified. Recently, we proposed a personalized immunotherapy approach to target the full spectrum of a patient's individual tumour-specific mutations. Here we show in three independent murine tumour models that a considerable fraction of non-synonymous cancer mutations is immunogenic and that, unexpectedly, the …