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The CD20 calcium channel is localized to microvilli and constitutively associated with membrane rafts: antibody binding increases the affinity of the association through an epitope-dependent cross-linking-independent mechanism
Journal article   Open access   Peer reviewed

The CD20 calcium channel is localized to microvilli and constitutively associated with membrane rafts: antibody binding increases the affinity of the association through an epitope-dependent cross-linking-independent mechanism

Haidong Li, Linda M Ayer, Maria J Polyak, Cathlin M Mutch, Ryan J Petrie, Laura Gauthier, Neda Shariat, Michael J Hendzel, Andrew R Shaw, Kamala D Patel, …
The Journal of biological chemistry, v 279(19), pp 19893-19901
07 May 2004
PMID: 14976189
url
http://www.jbc.org/content/279/19/19893.full.pdfView
Published, Version of Record (VoR) Open
url
https://doi.org/10.1074/jbc.M400525200View
Published, Version of Record (VoR) Open

Abstract

Actins - chemistry Adenosine Triphosphate - chemistry Antigens, CD20 - metabolism CD59 Antigens - biosynthesis Cell Line, Tumor Cell Membrane - metabolism Cross-Linking Reagents - pharmacology Cytochalasin D - pharmacology Detergents - pharmacology Epitopes - chemistry Flow Cytometry Humans Membrane Microdomains - metabolism Microscopy, Electron Microscopy, Fluorescence Microvilli - metabolism Models, Chemical Octoxynol - pharmacology Protein Conformation Time Factors Transfection
CD20 is a B cell-specific membrane protein that functions in store-operated calcium entry and serves as a useful target for antibody-mediated therapeutic depletion of B cells. Antibody binding to CD20 induces a diversity of biological effects, some of which are dependent on lipid rafts. Rafts are isolated as low density detergent-resistant membranes, initially characterized using Triton X-100. We have previously reported that CD20 is soluble in 1% Triton but that antibodies induce the association of CD20 with Triton-resistant rafts. However, by using several other detergents to isolate rafts and by microscopic co-localization with a glycosylphosphatidylinositol-linked protein, we show in this report that CD20 is constitutively raft-associated. CD20 was distributed in a punctate pattern on the cell surface as visualized by fluorescence imaging and was also localized to microvilli by electron microscopy. The mechanism underlying antibody-induced association of CD20 with Triton-resistant rafts was investigated and found not to require cellular ATP, kinase activity, actin polymerization, or antibody cross-linking but was dependent on the epitope recognized. Thus, antibody-induced insolubility in 1% Triton most likely reflects a transition from relatively weak to strong raft association that occurs as a result of a conformational change in the CD20 protein.

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Collaboration types
Domestic collaboration
Web of Science research areas
Biochemistry & Molecular Biology
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