Regulation of ZAP-70 intracellular localization: visualization with the green fluorescent protein.
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.
Sloan-Lancaster
J
J
Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, Bethesda, Maryland 20892, USA.
Zhang
W
W
Presley
J
J
Williams
B L
BL
Abraham
R T
RT
Lippincott-Schwartz
J
J
Samelson
L E
LE
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000941:Antigens / Q000235:genetics; D019556:COS Cells; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D002467:Cell Nucleus / Q000737:chemistry / Q000201:enzymology / Q000235:genetics; D002999:Clone Cells; D004789:Enzyme Activation / Q000235:genetics; D019085:Fluorescent Antibody Technique, Direct; D049452:Green Fluorescent Proteins; D006801:Humans; D007424:Intracellular Fluid / Q000201:enzymology*; D019169:Jurkat Cells; D008164:Luminescent Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000235:genetics / Q000502:physiology; D009685:Nuclear Envelope / Q000737:chemistry; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism; D013194:Staining and Labeling; D014443:Tyrosine / Q000378:metabolism; D051746:ZAP-70 Protein-Tyrosine Kinase
D000911:Antibodies, Monoclonal; D000941:Antigens; D008164:Luminescent Proteins; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human