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"Federici, L."
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ATP2C1 gene mutations in Hailey–Hailey disease and possible roles of SPCA1 isoforms in membrane trafficking
2016
ATP2C1
gene codes for the secretory pathway Ca
2+
/Mn
2+
-ATPase pump type 1 (SPCA1) localizing at the golgi apparatus. Mutations on the human
ATP2C1
gene, causing decreased levels of the SPCA1 expression, have been identified as the cause of the Hailey–Hailey disease, a rare skin disorder. In the last few years, several mutations have been described, and here we summarize how they are distributed along the gene and how missense mutations affect protein expression. SPCA1 is expressed in four different isoforms through alternative splicing of the
ATP2C1
gene and none of these isoforms is differentially affected by any of these mutations. However, a better understanding of the tissue specific expression of the isoforms, their localization along the secretory pathway, their specific binding partners and the role of the C-terminal tail making isoforms different from each other, will be future goals of the research in this field.
Journal Article
The fine-tuning of TRAF2–GSTP1-1 interaction: effect of ligand binding and in situ detection of the complex
2014
We provide the first biochemical evidence of a direct interaction between the glutathione transferase P1-1 (GSTP1-1) and the TRAF domain of TNF receptor-associated factor 2 (TRAF2), and describe how ligand binding modulates such an equilibrium. The dissociation constant of the heterocomplex is
K
d
=0.3
μ
M; however the binding affinity strongly decreases when the active site of GSTP1-1 is occupied by the substrate GSH (
K
d
≥2.6
μ
M) or is inactivated by oxidation (
K
d
=1.7
μ
M). This indicates that GSTP1-1’s TRAF2-binding region involves the GSH-binding site. The GSTP1-1 inhibitor NBDHEX further decreases the complex’s binding affinity, as compared with when GSH is the only ligand; this suggests that the hydrophobic portion of the GSTP1-1 active site also contributes to the interaction. We therefore hypothesize that TRAF2 binding inactivates GSTP1-1; however, analysis of the data, using a model taking into account the dimeric nature of GSTP1-1, suggests that GSTP1-1 engages only one subunit in the complex, whereas the second subunit maintains the catalytic activity or binds to other proteins. We also analyzed GSTP1-1’s association with TRAF2 at the cellular level. The TRAF2–GSTP1-1 complex was constitutively present in U-2OS cells, but strongly decreased in S, G2 and M phases. Thus the interaction appears regulated in a cell cycle-dependent manner. The variations in the levels of individual proteins seem too limited to explain the complex’s drastic decline observed in cells progressing from the G0/G1 to the S–G2–M phases. Moreover, GSH’s intracellular content was so high that it always saturated GSTP1-1. Interestingly, the addition of NBDHEX maintains the TRAF2–GSTP1-1 complex at low levels, thus causing a prolonged cell cycle arrest in the G2/M phase. Overall, these findings suggest that a reversible sequestration of TRAF2 into the complex may be crucial for cell cycle progression and that multiple factors are involved in the fine-tuning of this interaction.
Journal Article
The Crystal Structure of Polygalacturonase-Inhibiting Protein (PGIP), a Leucine-Rich Repeat Protein Involved in Plant Defense
by
Di Matteo, A.
,
De Lorenzo, G.
,
Johnson, K. A.
in
Acetates
,
Amino Acid Sequence
,
Biological Sciences
2003
Polygalacturonase-inhibiting proteins (PGIPs) are plant cell wall proteins that protect plants from fungal invasion. They interact with endopolygalacturonases secreted by phytopathogenic fungi, inhibit their enzymatic activity, and favor the accumulation of oligogalacturonides, which activate plant defense responses. PGIPs are members of the leucine-rich repeat (LRR) protein family that in plants play crucial roles in development, defense against pathogens, and recognition of beneficial microbes. Here we report the crystal structure at 1.7-Å resolution of a PGIP from Phaseolus vulgaris. The structure is characterized by the presence of two β-sheets instead of the single one originally predicted by modeling studies. The structure also reveals a negatively charged surface on the LRR concave face, likely involved in binding polygalacturonases. The structural information on PGIP provides a basis for designing more efficient inhibitors for plant protection.
Journal Article
Upgrade of the Belle II Vertex Detector with Depleted Monolithic Active Pixel Sensors
by
Lacasta, C.
,
Higuchi, T.
,
Bergauer, T.
in
belle ii
,
cmos pixel sensor
,
depleted monolithic active pixel sensor dmaps
2025
The Belle II experiment at the SuperKEKB e + e − collider is preparing for an upgrade of its vertex detector to cope with an increased luminosity of up to 6 × 10 35 cm −2 s −1 . The new vertex detector (VTX) will consist of six layers of depleted monolithic active pixel sensors (DMAPS), with a total material budget of about 3% of X 0 . The OBELIX chip, developed for this upgrade, is derived from the TJ-Monopix2 sensor and manufactured using the Tower Semiconductor 180 nm CMOS technology. It features a 33 µ m pixel pitch, time-stamping capability with 50 ns resolution, and a dedicated digital periphery compatible with the Belle II trigger system, supporting rates up to 30 kHz. The sensor is designed to operate under the expected background hit rate at the target luminosity, with high radiation tolerance, up to 5 × 10 14 n eq /cm 2 and 1 MGy, while maintaining a power density in the range of 200-300 mW/cm 2 , corresponding to hit rates from a few MHz/cm 2 up to 120 MHz/cm 2 . This paper presents results from laboratory measurements and beam tests performed on TJ-Monopix2 chips, including both not-irradiated and irradiated devices. Particular focus is given to the performance of irradiated sensors as a function of temperature, a key aspect for defining the maximum allowable operating temperature for OBELIX. These studies provide essential input for the thermal design of the VTX cooling system, especially for the innermost layers where power density and hit rates are highest.
Journal Article
Concurrent Validity of a New Contact Mat for Estimating Vertical Jump Height
2016
The vertical jump is a commonly used test and widely studied in literature. Indeed, it is one of the most prevalent method of assessment on sport performance because the jump height is highly correlated with leg extensor muscles power. This paper deals with the study on a new contact mat system whose performances have been compared with a force platform. Some tests have been performed and the relative comparative results will be presented. The study shows a significant concurrent validity of Wi-JumpLe system for the flight and ground contact time measurements. In conclusion, the new contact mat structure together with the electronic measurement system is legitimate to assess vertical jump height and leg extensors muscle power.
Journal Article
Structural Requirements of endopolygalacturonase for the Interaction with PGIP (Polygalacturonase-Inhibiting Protein)
by
Caprari, C.
,
Di Matteo, A.
,
De Lorenzo, G.
in
Active sites
,
Amino acids
,
antagonists & inhibitors
2001
To invade a plant tissue, phytopathogenic fungi produce several cell wall-degrading enzymes; among them, endopolygalacturonase (PG) catalyzes the fragmentation and solubilization of homogalacturonan. Polygalacturonase-inhibiting proteins (PGIPs), found in the cell wall of many plants, counteract fungal PGs by forming specific complexes with them. We report the crystal structure at 1.73 Å resolution of PG from the phytopathogenic fungus Fusariurn moniliforme (FmPG). The structure of FmPG was useful to study the mode of interaction of the enzyme with PGIP-2 from Phaseolus vulgaris. Several amino acids of FmPG were mutated, and their contribution to the formation of the complex with PGIP-2 was investigated by surface plasmon resonance. The residues Lys-269 and Arg-267, located inside the active site cleft, and His-188, at the edge of the active site cleft, are critical for the formation of the complex, which is consistent with the observed competitive inhibition of the enzyme played by PGIP-2. The replacement of His-188 with a proline or the insertion of a tryptophan after position 270, variations that both occur in plant PGs, interferes with the formation of the complex. We suggest that these variations are important structural requirements of plant PGs to prevent PGIP binding.
Journal Article
Structural investigation of nucleophosmin interaction with the tumor suppressor Fbw7γ
2017
Nucleophosmin (NPM1) is a multifunctional nucleolar protein implicated in ribogenesis, centrosome duplication, cell cycle control, regulation of DNA repair and apoptotic response to stress stimuli. The majority of these functions are played through the interactions with a variety of protein partners. NPM1 is frequently overexpressed in solid tumors of different histological origin. Furthermore NPM1 is the most frequently mutated protein in acute myeloid leukemia (AML) patients. Mutations map to the C-terminal domain and lead to the aberrant and stable localization of the protein in the cytoplasm of leukemic blasts. Among NPM1 protein partners, a pivotal role is played by the tumor suppressor Fbw7γ, an E3-ubiquitin ligase that degrades oncoproteins like c-MYC, cyclin E, Notch and c-jun. In AML with NPM1 mutations, Fbw7γ is degraded following its abnormal cytosolic delocalization by mutated NPM1. This mechanism also applies to other tumor suppressors and it has been suggested that it may play a key role in leukemogenesis. Here we analyse the interaction between NPM1 and Fbw7γ, by identifying the protein surfaces implicated in recognition and key aminoacids involved. Based on the results of computational methods, we propose a structural model for the interaction, which is substantiated by experimental findings on several site-directed mutants. We also extend the analysis to two other NPM1 partners (HIV Tat and CENP-W) and conclude that NPM1 uses the same molecular surface as a platform for recognizing different protein partners. We suggest that this region of NPM1 may be targeted for cancer treatment.
Journal Article
A decision tree for genetic diagnosis of hereditary periodic fever in unselected patients
2006
Background: The diagnostic value of molecular analysis of the familial Mediterranean fever (FMF) gene (Mediterranean fever (MEFV)) has been well established only in patients selected on the basis of ethnic background or clinical criteria. Genetic diagnosis for other hereditary periodic fever syndromes has been poorly evaluated. Objective: To determine the diagnostic contribution of genetic tests for hereditary periodic syndromes in a large, unselected series of patients. Methods: A retrospective study was conducted on 1941 patients referred to us for FMF genetic tests between 1997 and 2005. MEFV genotypes were compared with clinical data to appraise criteria for FMF diagnosis. Genetic tests for tumour necrosis factor receptor-associated periodic syndrome (TRAPS), hyperimmunoglobulinaemia D syndrome (HIDS) and cryopyrin-associated periodic syndromes (CAPS) were also reviewed. Results: 71% of the 1574 patients with enough data had a clinical diagnosis of FMF according to the widely used Israeli criteria. Two MEFV mutations were found in only 409 patients of this subgroup (sensitivity = 37%) and in 15 (3.3%) of the patients with an improbable clinical diagnosis of FMF (specificity = 97%). Molecular diagnosis for alternate hereditary periodic syndromes was carried out in 456 of the patients having a non-conclusive FMF genetic test. A positive diagnosis was obtained in 31 of these patients (TRAPS (n = 19), HIDS (n = 4) and CAPS (n = 8)). Conclusions: First-line MEFV mutation screening in patients with clinically typical FMF may be appropriate only in particular areas. To optimise genetic diagnosis, we propose a decision tree, which, with the advice of an expert practitioner, could help redirect test indications towards non-FMF hereditary periodic syndromes.
Journal Article
Refractory auto-inflammatory syndrome associated with digenic transmission of low-penetrance tumour necrosis factor receptor-associated periodic syndrome and cryopyrin-associated periodic syndrome mutations
by
Federici, L
,
Touitou, I
,
Jorgensen, C
in
Adult
,
Carrier Proteins - genetics
,
Familial Mediterranean Fever - genetics
2006
Following publications describing the efficacy of etanercept (enbrel), a recombinant human TNF receptor 1B fusion protein in patients with TRAPS 3 and anakinra (kineret), a recombinant human interleukin-1 (IL1)-receptor antagonist, in patients with CAPS, 4 targeted biotherapies have been repeatedly and successfully given for these two conditions. The proband's daughter, aged 8 years, had fever, urticaria and oral aphthosis. Because these phenotypes overlapped with symptoms reported for TRAPS and CAPS, we first sequenced TNFRSF1A exons 2-4 and CIAS1 exon 3, thereby covering 98% of the known mutations in both genes.
Journal Article