ZAP-70 association with T cell receptor zeta (TCRzeta): fluorescence imaging of dynamic changes upon cellular stimulation

The nonreceptor protein tyrosine kinase ZAP-70 is a critical enzyme required for successful T lymphocyte activation. After antigenic stimulation, ZAP-70 rapidly associates with T cell receptor (TCR) subunits. The kinetics of its translocation to the cell surface, the properties of its specific interaction with the TCRzeta chain expressed as a chimeric protein (TTzeta and Tzetazeta), and its mobility in different intracellular compartments were studied in individual live HeLa cells, using ZAP-70 and Tzetazeta fused to green fluorescent protein (ZAP-70 GFP and Tzetazeta-GFP, respectively). Time-lapse imaging using confocal microscopy indicated that the activation-induced redistribution of ZAP-70 to the plasma membrane, after a delayed onset, is of long duration. The presence of the TCRzeta chain is critical for the redistribution, which is enhanced when an active form of the protein tyrosine kinase Lck is coexpressed. Binding specificity to TTzeta was indicated using mutant ZAP-70 GFPs and a truncated zeta chimera. Photobleaching techniques revealed that ZAP-70 GFP has decreased mobility at the plasma membrane, in contrast to its rapid mobility in the cytosol and nucleus. Tzetazeta- GFP is relatively immobile, while peripherally located ZAP-70 in stimulated cells is less mobile than cytosolic ZAP-70 in unstimulated cells, a phenotype confirmed by determining the respective diffusion constants. Examination of the specific molecular association of signaling proteins using these approaches has provided new insights into the TCRzeta-ZAP-70 interaction and will be a powerful tool for continuing studies of lymphocyte activation.     

Agreement set and anticontent attitudes in the F scale: A reinterpretation.

The results of Peabody's (1961) study of attitude content and agreement set, presumably finding 2 kinds of Ss, one prone to agree irrespective of item content, the other likely to take an antiauthoritarian position irrespective of item direction, were reanalyzed. An alternative hypothesis was proposed, which explained the asymmetric results as mainly due to asymmetric reversals of F Scale items and consequent displacement of the neutral points of the reversed items. This displacement made the Ss scoring low on the original scale appear consistent, and the high scorers appear inconsistent in their attitudes at the phenotypic level. Yet while there is some evidence of possible response set, the majority of responses by most Ss seem perfectly consistent if the variation in item location is taken into account. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Programming in a wide spectrum language: a collection of examples

The paper exemplifies programming in a wide spectrum language by presenting styles which range from non-operative specifications—using abstract types and tools from predicate logic as well as set theory—over recursive functions, to procedural program with variables. Besides a number of basic types, we develop an interpreter for parts of the language itself, an algorithm for applying transformation rules to program representations, a text editor, and a simulation of Backus' functional programming language.     

H. H. Goddard and the immigrants.

Responds to comments by D. D. Dorfman (see record 1982-25821-001), D. Gersh (see record 1982-25825-001), R. J. Herrnstein (1981), and L. J. Kamin (see record 1982-25833-001) on the source of data cited in H. H. Goddard's (1917) article on mental tests with immigrants. An attempt is made to clarify what the cited data about the immigrants represent. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Activation of nuclear factor of activated T cells-(NFAT) and activating protein 1 (AP-1) by oncogenic 70Z Cbl requires an intact phosphotyrosine binding domain but not Crk(L) or p85 phosphatidylinositol 3-kinase association

The Cbl proto-oncogene product is a complex adapter protein that functions as a negative regulator of protein tyrosine kinases. It is rapidly tyrosine-phosphorylated and associates with Crk(L) and p85 phosphatidylinositol 3-kinase (PI3K) upon engagement of numerous receptors linked to tyrosine kinases. Elucidation of the mechanism(s) underlying Cbl deregulation is therefore of considerable interest. The 70Z Cbl oncoprotein shows increased baseline tyrosine phosphorylation in fibroblasts and enhances nuclear factor of activated T cells (NFAT) activity in Jurkat T cells. Its transforming ability has been proposed to relate to its increased phosphotyrosine content. We demonstrate that 70Z Cbl shows increased basal and activation-induced tyrosine phosphorylation and association with Crk(L) and p85 PI3K in Jurkat T cells. 70Z Cbl, however, retains the ability to enhance NFAT and activating protein 1 (AP1) activity in the absence of Crk(L)/p85 PI3K association. In contrast, the G306E mutation, which inactivates the phosphotyrosine binding domain of Cbl, blocks NFAT/AP1 activation by 70Z Cbl. We conclude that 70Z Cbl-induced NFAT/AP1 activation requires the phosphotyrosine binding domain but not Crk(L)/p85 PI3K association. We hypothesize that 70Z Cbl acts as a dominant negative by blocking the negative regulatory function of the Cbl phosphotyrosine binding domain on protein-tyrosine kinases.     

LAT is required for TCR-mediated activation of PLCgamma1 and the Ras pathway

In this study, we present the further characterization of a mutant Jurkat T cell line, J.CaM2, that is defective in TCR-mediated signal transduction. Although initial TCR-mediated signaling events such as the inducible tyrosine phosphorylation of the TCR-zeta chain and ZAP-70 are intact in J.CaM2, subsequent events, including increases in intracellular calcium, Ras activation, and IL-2 gene expression are defective. Subsequent analysis of J.CaM2 demonstrated a severe deficiency in pp36/LAT expression, a recently cloned adaptor protein implicated in TCR signaling. Importantly, reexpression of LAT in J.CaM2 restored all aspects of TCR signaling. These results demonstrate a necessary and exclusive role for LAT in T cell activation.     

Long-pulse laser emission from rhodamine 6G

The properties of the rhodamine 6G flashlamp-pumped circulating dye laser with cyclooctatetraene and cycloheptatriene as triplet-state quenchers are described. Particular attention is given to such observables as pulse duration, frequency sweep, and early termination of the laser pulse. From the experimental results and the theory of dye lasers, it is concluded that the thermal effects may not play a dominant role in such lasers.     

Output properties of the Nd+3:SeOCl2liquid laser

Laser action in the liquid medium Nd⁺³: SeOCl2is described. Details concerning the cell construction and the dependence of output on cell geometry and optical feedback are presented. Output energies of 13 joules with a differential efficiency of 1 percent are reported. An interpretation is offered for the phenomenon of self-Q-switching or the generation of multimegawatt spikes at low values of optical feedback.     

Research Dependent on Deception Increases the Psychological Pollution of the World.

This commentary confronts the use of deception in psychological experiments. A subject enters a psychological experiment with an attitude of trust. After the experimenter has manipulated the subject by means of deception, he will dehoax him, and this dehoaxing has become a standard part of such experiments. The subject of a deception-based experiment knows from personal experience that at least one psychologist in his professional role as a psychologist uses deception. Such a subject may never enter another psychological experiment with a trusting attitude. For some subjects it might even generalize further to a less trustful attitude toward people in general. Here then is the psychological pollution: the generation by psychologists of mistrust between individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)