Binding of CD44 to hyaluronic acid can be induced by multiple signals and requires the CD44 cytoplasmic domain.
Human Jurkat T cells transfected with a human CD44H gene do not bind fluorescein-conjugated hyaluronic acid (F-HA). Activation of Jurkat CD44 transfectant is required for binding to F-HA. Binding can be induced by anti-CD3 monoclonal antibody (Mab), PMA, calcium ionophore, forskolin, or a monoclonal anti-CD44 Mab (F10-44-2). Cytochalasin D, an inhibitor of actin polymerization, inhibited both PMA-induced and anti-CD44 Mab-induced binding. In contrast, only PMA-induced binding was blocked by inhibitors of microtubule functions: colchicine or Taxol. Therefore, binding induced by PMA and anti-CD44 Mab involves different cytoskeletal proteins. The conclusion that interactions between CD44 and cytoskeletal proteins are important for binding was further supported by our observations that the cytoplasmic domain of CD44 is required for both PMA- and anti-CD44 Mab-induced binding. Jurkat CD44 mutant transfectant lacking the last 23 amino acids of the cytoplasmic domain can be induced to bind FHA. In contrast, Jurkat mutant CD44 transfectant lacking the last 57 amino acids of the cytoplasmic domain was unable to bind. Collectively, these data provide supportive evidence that binding activity of CD44 is under the regulation of multiple signal pathways and requires the presence of the cytoplasmic domain.
Liu
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Institute of Pathology, Skin Disease Research Center, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106-4943, USA.
Zhang
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Mori
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D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology; D003078:Colchicine / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D015638:Cytochalasin D / Q000494:pharmacology; D003593:Cytoplasm / Q000737:chemistry; D003598:Cytoskeletal Proteins / Q000378:metabolism; D003599:Cytoskeleton / Q000502:physiology; D006801:Humans; D018960:Hyaluronan Receptors / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000378:metabolism*; D015759:Ionomycin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D019169:Jurkat Cells; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017239:Paclitaxel / Q000494:pharmacology; D014176:Protein Biosynthesis; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection
D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D003598:Cytoskeletal Proteins; D018960:Hyaluronan Receptors; D007476:Ionophores; D005576:Colforsin; D015638:Cytochalasin D; D015759:Ionomycin; D006820:Hyaluronic Acid; D003513:Cycloheximide; D000242:Cyclic AMP; D013755:Tetradecanoylphorbol Acetate; D017239:Paclitaxel; D003078:Colchicine