In order to find a highly sensitive fluorophore, 3-azolyl-7-diethylaminocoumarin derivatives were synthesized. Both the absorption and fluorescence maxima of the coumarin-thiazole compounds showed red shifts with increases of the molar absorptivities and fluorescence intensities, in comparison with those of the corresponding coumarin-oxazole compounds. Among them, 3-(5-ethoxycarbonyl-1,3-thiazol-2-yl)-7-diethylamino-2H-chromen -2-one (3e) was one of the most promising candidates as a fluorophore accessible for analytical purposes in the fields of analytical and biological chemistry.
The tyrosine kinases Jak1 and Jak3 are known to be associated with the beta and gamma chains of interleukin-2 receptor (IL-2R). They are activated by stimulation with IL-2, IL-4, IL-7, IL-9, or IL-15, receptors of which share the gamma chain of the IL-2R. We have obtained direct evidence of Jak1 association with the alpha chains of receptors for IL-4, IL-7 and IL-9 and with the beta chain of IL-2R, which is also common to the IL-15R. Furthermore, we have prepared mutant IL-2R beta chains with a mutation in the box 1 region, which is conserved among the IL-2R beta chain and the alpha chains of the other cytokine receptors sharing the IL-2R gamma chain. Using MOLT-4 transfectants with the mutant beta chains, we found that two conserved proline residues within the box 1 region are essentially involved in association with Jak1. The MOLT-4 transfectants with the mutant beta chains lacking Jak1 association showed IL-2 responsiveness, in terms of activation of Jak3 and Stat5 and induction of cell growth, indicating that Jak1 is dispensable for IL-2-mediated cell growth signaling and that Jak1 activation is not required for activation of Jak3 and Stat5 in the MOLT-4 transfectants.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.