We recently reported that the rat asialoglycoprotein receptor binds oligosaccharides terminating with sialic acid (Sia) alpha2,6GalNAc. Despite a high percentage of identical amino acids in their sequences, orthologues of the asialoglycoprotein receptor (ASGP-R) in different mammals differ in their specificity for terminal Siaalpha2,6GalNAc. The recombinant subunit 1 of the ASGP-R from the rat (RHL-1 or rat hepatic lectin) and the mouse (MHL-1 or mouse hepatic lectin), which differ at only 12 positions in the amino acid sequence of their carbohydrate recognition domains, binds Siaalpha2,6GalNAcbeta1,4GlcNAcbeta1,2Man-bovine serum albumin and GalNAcbeta1,4GlcNAcbeta1,2Man-bovine serum albumin in ratios of 16:1.0 and 1.0:1.0, respectively. Mutagenesis was used to show that amino acids both in the immediate vicinity of the proposed binding site for terminal GalNAc and on the alpha2 helix that is distant from the binding site contribute to the specificity for terminal Siaalpha2,6GalNAc. Thus, multiple amino acid sequence alterations in two key locations contribute to the difference in specificity observed for the rat and mouse ASGP-Rs. We hypothesize that the altered specificity of ASPG-R orthologues in such evolutionarily closely related species reflects rapidly changing requirements for recognition of endogenous or exogenous oligosaccharides in vivo.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1074/jbc.M406647200 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Whole-Body Physiologically Based Pharmacokinetic Modeling of GalNAc-Conjugated siRNAs.
Pharmaceutics
January 2025
Department of Pharmaceutical Bioscience, Translational Drug Discovery and Development, Uppsala University, SE-75124 Uppsala, Sweden.
: N-acetyl-galactosamine small interfering RNAs (GalNAc-siRNA) are an emerging class of drugs due to their durable knockdown of disease-related proteins. Direct conjugation of GalNAc onto the siRNA enables targeted uptake into hepatocytes via GalNAc recognition of the Asialoglycoprotein Receptor (ASGPR). With a transient plasma exposure combined with a prolonged liver half-life, GalNAc-siRNA exhibits distinct disposition characteristics.
View Article and Find Full Text PDFIntegrated SegFlow, µSIA, and UPLC for Online Sialic Acid Quantitation of Glycoproteins Directly from Bioreactors.
Eng Life Sci
January 2025
Analytical Development & Analytical Attribute Science in Biologics Bristol Myers Squibb Devens Massachusetts USA.
This study emphasizes the critical importance of closely monitoring and controlling the sialic acid content in therapeutic glycoproteins, including EPO, interferon-γ, Orencia, Enbrel, and others, as the level of sialylation directly impacts their pharmacokinetics (PK), immunogenicity, potency, and overall clinical performance due to its influence on protein clearance via hepatic asialoglycoprotein receptors (ASGPR). The ASGPR recognizes and binds to glycoproteins exposed to terminal galactose or N-acetylgalactosamine residues, leading to receptor-mediated endocytosis. Recent studies have demonstrated that sialylation of O-linked glycan plays a role in protecting against macrophage galactose lectin (MGL)-mediated clearance.
View Article and Find Full Text PDFPreparation of oat galactolipid and anti-liver cancer effects of oat galactolipid-modified curcumin-loaded liver targeting vesicle.
Front Pharmacol
January 2025
Hubei Shizhen Laboratory, Wuhan, China.
Introduction: The mortality rate for liver cancer is extremely high but clinical treatments have not made much progress, so it is necessary to develop anticancer agents with lower toxicities and more effective liver-targeting drug delivery systems (LTDDSs). At present, LTDDSs mediated by the asialoglycoprotein receptor (ASGPR) show excellent effects at improving the liver-targeting and antitumor effects of drugs. However, the galactosyl ligands are typically prepared by chemical synthesis and have some shortcomings.
View Article and Find Full Text PDFTargeted Degradation of HCV Polymerase by GalNAc-Conjugated ApTACs for Pan-Genotypic Antiviral Therapy with High Resistance Barriers.
J Med Chem
January 2025
Department of Ophthalmology, Tianjin Medical University General Hospital, International Joint Laboratory of Ocular Diseases (Ministry of Education), Tianjin Key Laboratory of Ocular Trauma, Tianjin Institute of Eye Health and Eye Diseases, China-U.K. "Belt and Road" Ophthalmology Joint Laboratory, Laboratory of Molecular Ophthalmology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Medical University, Tianjin 300070, China.
Hepatitis C virus (HCV) infection is a major cause of chronic liver disease. Although interferon-free direct-acting antivirals have led to significant advancements in the treatment of HCV infection, the high genetic variability of the virus and the emergence of acquired drug resistance pose potential threats to their effectiveness. In this study, we develop a broad-spectrum aptamer-based proteolysis targeting chimera, designated dNS5B, which effectively degrades both pan-genotypic NS5B polymerase and drug-resistant mutants through ubiquitin proteasome system.
View Article and Find Full Text PDFAn updated systematic review about various effects of microplastics on cancer: A pharmacological and in-silico based analysis.
Mol Aspects Med
February 2025
Stem Cells Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Epidemiology, West Kazakhstan Marat Ospanov Medical University, Aktobe, Kazakhstan; Department of Natural Sciences, West Kazakhstan Marat Ospanov Medical University, Aktobe, Kazakhstan. Electronic address:
Microplastics (MPs) are known as substantial environmental and health threats because of their pervasive existence and potential function in human diseases. This study is the first research in which a comprehensive analysis of various impacts of MPs on cancer cells is performed through pharmacological and in silico approaches. Moreover, our results demonstrate that MPs have both promotive and suppressive impacts on cancer cells, changing some of the important features of these kinds of cells including cellular viability, migration, metastasis, and apoptosis.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!