HIV-1 Vpu induces downregulation of cell surface NTB-A to evade lysis of HIV-1 infected cells by NK cells. Here we show that Vpu affects the anterograde transport and the glycosylation pattern of NTB-A by a mechanism that is distinct from the Vpu induced downregulation of CD4 and tetherin. In the presence of Vpu, only the high mannose form of NTB-A was detectable, suggesting that Vpu prevented the formation of the mature form of NTB-A. This phenomenon is associated with the ability of Vpu to downregulate cell surface NTB-A by retention of NTB-A within the Golgi-compartment. Furthermore, the Vpu-mediated effect on NTB-A glycosylation is highly conserved among Vpu proteins derived from HIV-1 and SIV and corresponds to the level of downregulation of NTB-A. Together, these results suggest that the reduction of NTB-A from the cell surface is associated with the Vpu-mediated effect on the glycosylation pattern of newly synthesized NTB-A molecules.
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http://dx.doi.org/10.1016/j.virol.2013.02.021 | DOI Listing |
Nano Lett
January 2025
Zhejiang Engineering Research Center for Tissue Repair Materials and Wenzhou Key Laboratory of Biomaterials and Engineering and Wenzhou Key Laboratory of Biophysics, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325001, China.
Saccharides and peptides with markedly disparate stereochemical features serve as pivotal chiral molecular partners in living systems. The importance of glycosylation in influencing glycopeptide self-assembly has been recognized. However, how different chiral combinations of saccharides and peptides influence the macroscopic hydrogel mechanics, fiber nanomechanics, asymmetric molecular packing, and thermodynamic changes during glycopeptide self-assembly remains unknown.
View Article and Find Full Text PDFJ Carbohydr Chem
April 2024
Department of Chemistry, University of Florida, 214 Leigh Hall, Gainesville, FL 32611, USA.
Glycosylphosphatidylinositol (GPI) anchors contain a unique α-D-glucosamine-(1→6)--inositol [αGlcN(1,6)Ins] motif in their conserved core structure. To facilitate investigations of the functional roles of this structural motif, two GPI analogues containing unnatural βGlcN(1,6)Ins, instead of αGlcN(1,6)Ins, and an alkyne group at different positions of the GPI core were designed and synthesized. To this end, an orthogonally protected pseudopentasaccharide derivative of GPIs with the βGlcN(1,6)Ins motif was convergently constructed via [3+2] glycosylation and used as the common intermediate to prepare both GPI analogues by streamlined synthetic protocols.
View Article and Find Full Text PDFAppl Biochem Biotechnol
January 2025
Unidad de Biotecnología Industrial, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco A.C, 45019, Zapopan, Jal, Mexico.
Lipases from the basidiomycete fungus Ustilago maydis are promising but underexplored biocatalysts due to their high homology with Candida antarctica lipases. This study provides a comprehensive characterization of a recombinant CALB-like lipase from U. maydis, expressed in Pichia pastoris (rUMLB), and compares its properties with those of the well-studied recombinant lipase B from C.
View Article and Find Full Text PDFJ Virol
January 2025
Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, USA.
Discovered in 1994 in lesions of an AIDS patient, Kaposi's sarcoma-associated herpesvirus (KSHV) is a member of the gammaherpesvirus subfamily of the family, which contains a total of nine that infect humans. These viruses all contain a large envelope glycoprotein, glycoprotein B (gB), that is required for viral fusion with host cell membrane to initial infection. Although the atomic structures of five other human herpesviruses in their postfusion conformation and one in its prefusion conformation are known, the atomic structure of KSHV gB has not been reported.
View Article and Find Full Text PDFJ Chem Inf Model
January 2025
Department of Biochemistry, University of Oxford, Oxford OX1 3QU, U.K.
Sugars are ubiquitous in biology; they occur in all kingdoms of life. Despite their prevalence, they have often been somewhat neglected in studies of structure-dynamics-function relationships of macromolecules to which they are attached, with the exception of nucleic acids. This is largely due to the inherent difficulties of not only studying the conformational dynamics of sugars using experimental methods but indeed also resolving their static structures.
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