Galectin-3 stimulates uptake of extracellular Ca2+ in human Jurkat T-cells.
Galectin-3, a mammalian galactoside-binding protein, is not expressed in the Jurkat T-lymphoblastoid cell line. However, Jurkat cells express surface glycoprotein receptors for galectin-3, one of which is shown to be the glycosylated heavy chain of CD98 (4F2 antigen), a T-cell activation marker. Addition of galectin-3 to Jurkat cells triggers a sustained influx of extracellular Ca2+ in a concentration dependent manner. The induced increase in cytosolic [Ca2+]i is blocked by sugar hapten inhibitors of galectin-3. The galectin-3-induced effect is insensitive to voltage-gated Ca2+ channel antagonists such as prenylamine, nifedipine and diltiazem and to pertussis toxin but is inhibited by cholera toxin. The results suggest that galectin-3 released by accessory cells such as macrophages may bind in vivo to T-cell activation antigens and also participate in Ca2+ signalling.
National Institute for Medical Research, London, UK.
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D000818:Animals; D015703:Antigens, CD / Q000502:physiology; D000943:Antigens, Differentiation / Q000096:biosynthesis / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002352:Carrier Proteins / Q000502:physiology; D002460:Cell Line; D006224:Cricetinae; D005434:Flow Cytometry; D027261:Fusion Regulatory Protein-1; D037502:Galectin 3; D006031:Glycosylation; D006801:Humans; D019169:Jurkat Cells; D007700:Kinetics; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000502:physiology; D011994:Recombinant Proteins / Q000096:biosynthesis; D013601:T-Lymphocytes; D013755:Tetradecanoylphorbol Acetate
D015703:Antigens, CD; D000943:Antigens, Differentiation; D002121:Calcium Channel Blockers; D002352:Carrier Proteins; D027261:Fusion Regulatory Protein-1; D037502:Galectin 3; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium