β1,4-galactosyltransferase 4 (B4GalT4) is one of seven B4GalTs that belong to CAZy glycosyltransferase family 7 and transfer galactose to growing sugar moieties of proteins, glycolipids, glycosaminoglycans as well as single sugar for lactose synthesis. Herein, we identify two asparagine-linked glycosylation sites in B4GalT4. We found that mutation of one site (Asn220) had greater impact on enzymatic activity while another (Asn335) on Golgi localization and presence of N-glycans at both sites is required for production of stable and enzymatically active protein and its secretion. Additionally, we confirm B4GalT4 involvement in synthesis of keratan sulfate (KS) by generating A375 B4GalT4 knock-out cell lines that show drastic decrease in the amount of KS proteoglycans and no significant structural changes in N- and O-glycans. We show that KS decrease in A375 cells deficient in B4GalT4 activity can be rescued by overproduction of either partially or fully glycosylated B4GalT4 but not with N-glycan-depleted B4GalT4 version.
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http://dx.doi.org/10.1007/s10719-020-09941-z | DOI Listing |
Cell Mol Life Sci
January 2025
Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale Et Fonctionnelle, 59000, Lille, France.
Glycans are known to be fundamental for many cellular and physiological functions. Congenital disorders of glycosylation (CDG) currently encompassing over 160 subtypes, are characterized by glycan synthesis and/or processing defects. Despite the increasing number of CDG patients, therapeutic options remain very limited as our knowledge on glycan synthesis is fragmented.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Interactions with the Environment Program, Immune System Development and Function Unit, Centro de Biología Molecular Severo Ochoa (CBM), Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid, 28049 Madrid, Spain.
Nitric oxide synthases (NOS) are enzymes responsible for the cellular production of nitric oxide (NO), a highly reactive signaling molecule involved in important physiological and pathological processes. Given its remarkable capacity to diffuse across membranes, NO cannot be stored inside cells and thus requires multiple controlling mechanisms to regulate its biological functions. In particular, the regulation of endothelial nitric oxide synthase (eNOS) activity has been shown to be crucial in vascular homeostasis, primarily affecting cardiovascular disease and other pathophysiological processes of importance for human health.
View Article and Find Full Text PDFJ Immunother Cancer
January 2025
Department of Clinical Laboratory, The Third Medical Center of Chinese PLA General Hospital, Beijing, Beijing, China
Background: Immunotherapy that targets immune checkpoints has achieved revolutionary success, but its application in solid tumors remains limited, highlighting the need for reliable enhancement of the efficacy of immunotherapy. Golgi protein 73 (GP73), a Golgi membrane protein, has been implicated in various cellular processes, including immune regulation. Recent studies suggested that GP73 may play a role in modulating the immune response in patients with cancer.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Key Laboratory of Horticultural Crop Germplasm Innovation and Utilization (Co-Construction by Ministry and Province), Key Laboratory of Horticultural Crop Genetic Improvement and Eco-physiology of Anhui Province, Institute of Horticulture, Anhui Academy of Agricultural Sciences, Hefei 230031, China. Electronic address:
Seed hardness is an important quality characteristic of pomegranate fruit. The development of seed hardness relies on the deposition of lignin in the inner seed coat, but the underlying molecular mechanisms remain unclear. In this study, we identified a member of ABCG transporters, PgABCG9, which may function in seed hardening by negatively regulating lignin biosynthesis.
View Article and Find Full Text PDFFront Cell Dev Biol
December 2024
Departments of Biology, University of York, York, United Kingdom.
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