Biology subjects

Yoneda, Y.

Publications and source records attributed to Yoneda, Y..

3 recordsLinked to original sources

bioRxiv2021

SARS-CoV-2 ORF6 disturbs nucleocytoplasmic trafficking to advance the viral replication

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus responsible for the coronavirus disease 2019 pandemic. ORF6 is known to antagonize the interferon signaling by inhibiting the nuclear translocation of STAT1. Here we show that ORF6 acts as a virulence factor through two distinct strategies. First, ORF6 directly interacts with STAT1 in an IFN-independent manner to inhibit its nuclear translocation. Second, ORF6 directly binds to importin 1, which is a nuclear transport factor encoded by KPNA2, leading to a significant suppression of importin 1-mediated nuclear transport. Furthermore, we found that KPNA2 knockout enhances the viral replication, suggesting that importin 1 suppresses the viral propagation. Additionally, the analyses of gene expression data revealed that importin 1 levels decreased significantly in the lungs of older individuals. Taken together, SARS-CoV-2 ORF6 disrupts the nucleocytoplasmic trafficking to accelerate the viral replication, resulting in the disease progression, especially in older individuals.

microbiology↗

bioRxiv2020

Variable optical properties of light-harvesting complex II revisited

Understanding photosynthetic light harvesting requires knowledge of the molecular mechanisms that dissipate excess energy in thylakoids. However, it remains unclear how the physical environment of light-harvesting complex II (LHCII) influences the process of chlorophyll de-excitation. Here, we demonstrate that protein-protein interactions between LHCIIs affect the optical properties of LHCII and thus influence the total energy budget. Aggregation of LHCII in the dark altered its absorption properties, independent of the amount of prior light exposure. We also revisited the triplet excited state involved in light-induced fluorescence quenching and found another relaxation pathway involving emission in the green region, which might be related to triplet excited energy transfer to neighboring carotenoids and annihilation processes that result in photoluminescence. LHCII- containing liposomes with different protein densities exhibited altered fluorescence and scattering properties. Our results suggest that macromolecular reorganization affects overall optical properties, which need to be addressed to compare the level of energy dissipation.

plant biology↗

bioRxiv2020

Importin α2 associates with chromatin via a novel DNA binding domain

Nuclear transport of proteins is important for facilitating appropriate nuclear functions. The proteins of the importin family play key roles in nuclear transport as transport receptors for a huge number of nuclear proteins. Additionally, these proteins possess other functions, including chromatin association and gene regulation. However, these non-transport functions of importin are not yet fully understood, especially their molecular-level mechanisms for functioning with chromatin and their consequences. Here, we report the novel molecular characteristics of importin involving binding to diverse sequences in chromatin. We newly identified and characterized a DNA-binding domain--the Nucleic Acid Associating Trolley pole domain (NAAT domain)--in the N-terminal region of importin within the conventional importin {beta} binding (IBB) domain, which was shown to be necessary for nuclear transport of cargo proteins. We propose a stroll and locate model to explain the association of importin with chromatin. This is the first study to delineate the interaction between importin and chromatin DNA via the NAAT domain, indicating the bifunctionality of the importin N-terminal region for nuclear transport and chromatin association.

molecular biology↗