Insulin-degrading enzyme (IDE) hydrolyzes monomeric polypeptides, including amyloid-β (Aβ) and HIV-1 p6. It also acts as a nonproteolytic chaperone to prevent Aβ polymerization. Here we compare interactions of Aβ and non-amyloidogenic p6 with IDE. Although both exhibited similar proteolysis rates, the binding kinetics to an inactive IDE characterized using relaxation-based NMR were remarkably different. IDE and Aβ formed a sparsely populated complex with a lifetime of milliseconds in which a short hydrophobic cleavage segment of Aβ was anchored to IDE. Strikingly, a second and more stable complex was significantly populated with a subsecond lifetime owing to multiple intermolecular contacts between Aβ and IDE. By selectively sequestering Aβ in this nonproductive complex, IDE likely increases the critical concentration required for fibrillization. In contrast, IDE and p6 formed a transient, submillisecond complex involving a single anchoring p6 motif. Modulation of intermolecular interactions, thus, allows IDE to differentiate between non-amyloidogenic and amyloidogenic substrates.
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http://dx.doi.org/10.1021/acs.biochem.1c00342 | DOI Listing |
Stroke
January 2025
Department of Experimental Neurology, Center for Stroke Research Berlin (CSB), Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany (M.F., S.B., S.M., K.W., M.E., A.M., U.D., C.S.).
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Research Department, Purotech Bio Inc, Yokohama, Japan.
Hepatitis B virus (HBV) infects cells by attaching to heparan sulfate proteoglycans (HSPG) and Na/taurocholate cotransporting polypeptide (NTCP). The endothelial lipase LIPG bridges HSPG and HBV, facilitating HBV attachment. From a randomized peptide expression library, we identified a short sequence binding to LIPG.
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Department of Immunology and Rheumatology, Division of Advanced Preventive Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Individuals diagnosed with Castleman disease (CD) and TAFRO syndrome (characterized by thrombocytopenia, anasarca, fever, bone marrow fibrosis, and organomegaly) displays a wide range of clinical symptoms, including varying patterns of lymph node enlargement, systemic inflammation, and impaired organ function. Some patients may present with both CD and TAFRO syndrome concurrently. A retrospective study conducted across multiple centers in Japan examined 321 cases to determine if the quantity and position of swollen lymph nodes could forecast the clinical progression and intensity of these conditions.
View Article and Find Full Text PDFViruses
December 2024
Third Department of Internal Medicine, Faculty of Medicine, Academic Assembly, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
Achieving HBsAg seroclearance is a key goal in treating chronic hepatitis B virus (HBV) infection but remains difficult with nucleos(t)ide analogues (NAs). Tenofovir alafenamide fumarate (TAF), a recommended NA for managing chronic HBV infection (CHB), has uncertain effects on HBsAg levels and potential adverse events when used long-term after switching from entecavir (ETV). We retrospectively evaluated 77 CHB patients, including 47 who switched from ETV to TAF with a median follow-up of 40 months post-switch and a median of 60 months of HBsAg monitoring pre-switch.
View Article and Find Full Text PDFBiomolecules
January 2025
Department of Gastroenterology and Hepatology, Erasmus Medical Center, Wytemaweg 80, 3015CN Rotterdam, The Netherlands.
Hepatitis B virus (HBV) is a major global health issue, with an estimated 254 million people living with chronic HBV infection worldwide as of 2022. Chronic HBV infection is the leading cause of cirrhosis and liver cancer. Current treatment with nucleos(t)ide analogs is effective in the suppression of viral activity but generally requires lifelong treatment.
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