Regulation of ZAP-70 Intracellular Localization: Visualization with the Green Fluorescent Protein |
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| Authors: | Joanne Sloan-Lancaster Weiguo Zhang John Presley Brandi L Williams Robert T Abraham Jennifer Lippincott-Schwartz and Lawrence E Samelson |
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| Institution: | From *the Section on Lymphocyte Signaling and ‡the Unit of Organelle Biology, Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892; and §The Department of Immunology, Mayo Clinic, Rochester, Minnesota 55905 |
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| Abstract: | To investigate the cellular dynamics of ZAP-70, we have studied the distribution and regulation of its intracellular location using a ZAP-70 green fluorescent protein chimera. Initial experiments in epithelial cells indicated that ZAP-70 is diffusely located throughout the quiescent cell, and accumulates at the plasma membrane upon cellular activation, a phenotype enhanced by the coexpression of Lck and the initiation of ZAP-70 kinase activity. Subsequent studies in T cells confirmed this phenotype. Intriguingly, a large amount of ZAP-70, both chimeric and endogenous, resides in the nucleus of quiescent and activated cells. Nuclear ZAP-70 becomes tyrosine phosphorylated upon stimulation via the T cell receptor, indicating that it may have an important biologic function. |
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