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Glycosylation of a key cubilin Asn residue results in reduced binding to albumin

DIR@IMTECH: CSIR-Institute of Microbial Technology

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Title Glycosylation of a key cubilin Asn residue results in reduced binding to albumin
 
Creator Yadav, Shiv Pratap Singh
Yu, Aiying
Zhao, Jingfu
Singh, Jasdeep
Kakkar, Saloni
Chakraborty, Srinivas
Mechref, Yehia
Molitoris, Bruce
Wagner, Mark C.
 
Subject QR Microbiology
 
Description Kidney disease often manifests with an increase in proteinuria, which can result from both glomerular and/or proximal tubule injury. The proximal tubules are the major site of protein and peptide endocytosis of the glomerular filtrate, and cubilin is the proximal tubule brush border membrane glycoprotein receptor that binds filtered albumin and initiates its processing in proximal tubules. Albumin also undergoes multiple modifications depending upon the physiologic state. We previously documented that carbamylated albumin had reduced cubilin binding, but the effects of cubilin modifications on binding albumin remain unclear. Here, we investigate the cubilin-albumin binding interaction to define the impact of cubilin glycosylation and map the key glycosylation sites while also targeting specific changes in a rat model of proteinuria. We identified a key Asn residue, N1285, that when glycosylated reduced albumin binding. In addition, we found a pH-induced conformation change may contribute to ligand release. To further define the albumin-cubilin binding site, we determined the solution structure of cubilin's albumin-binding domain, CUB7,8, using small-angle X-ray scattering and molecular modeling. We combined this information with mass spectrometry crosslinking experiments of CUB7,8 and albumin that provides a model of the key amino acids required for cubilin-albumin binding. Together, our data supports an important role for glycosylation in regulating the cubilin interaction with albumin, which is altered in proteinuria and provides new insight into the binding interface necessary for the cubilin-albumin interaction.
 
Publisher Elsevier
 
Date 2022-08
 
Type Article
PeerReviewed
 
Relation https://www.sciencedirect.com/science/article/pii/S0021925822008146?via%3Dihub
http://crdd.osdd.net/open/3065/
 
Identifier Yadav, Shiv Pratap Singh and Yu, Aiying and Zhao, Jingfu and Singh, Jasdeep and Kakkar, Saloni and Chakraborty, Srinivas and Mechref, Yehia and Molitoris, Bruce and Wagner, Mark C. (2022) Glycosylation of a key cubilin Asn residue results in reduced binding to albumin. JOURNAL OF BIOLOGICAL CHEMISTRY, 298 (10).