1. Role of the cysteine-rich domain of the t-SNARE component, SYNDET, in membrane binding and subcellular localization.
- Author
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Koticha DK, Huddleston SJ, Witkin JW, and Baldini G
- Subjects
- Animals, Cell Membrane metabolism, Fluorescent Antibody Technique, Membrane Proteins genetics, Mice, Microscopy, Confocal, Microscopy, Immunoelectron, Mutagenesis, Site-Directed, Mutation genetics, Palmitates metabolism, Protein Binding, SNARE Proteins, Sequence Deletion genetics, Synaptosomal-Associated Protein 25, Transfection genetics, Tumor Cells, Cultured, Cysteine genetics, Membrane Proteins metabolism, Nerve Tissue Proteins metabolism, Vesicular Transport Proteins
- Abstract
Wild-type syndet is efficiently recruited at the plasma membrane in transfected AtT-20 cells. A deletion at the cysteine-rich domain abolishes palmitoylation, membrane binding, and plasma membrane distribution of syndet. Syndet, SNAP-25A, and SNAP-25B share four cysteine residues, of which three, Cys2, Cys4, and Cys5, are absolutely conserved in all three homologs. Mutations at any pair of cysteines within cysteines 2, 4, and 5 shift syndet from the cell surface into the cytoplasm. Thus, at least two cysteines within the conserved triplet are necessary for plasma membrane localization. Syndet C1S/C3S, with substitutions at the pair Cys1 and Cys3, distributes to the plasma membrane, a Golgi-like compartment, and the cytosol. We conclude that Cys1 and Cys3 are not absolutely necessary for membrane binding or plasma membrane localization. Our results show that the cysteine-rich domain of syndet plays a major role in its subcellular distribution.
- Published
- 1999
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