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The Ca2+/calmodulin (CaM)-dependent protein phosphatase calcineurin is rapidly phosphorylated (0.8 mol of 32PO4 per mol of 60-kDa subunit of calcineurin) by brain Ca2+/CaM-dependent protein kinase II (CaM-kinase II). This reaction requires the autophosphorylated, Ca2+-independent form of CaM-kinase II since Ca2+/CaM binding to calcineurin inhibits(More)
Calcineurin, a Ca2+/calmodulin-dependent phosphoprotein phosphatase found in several tissues, is highly concentrated in mammalian brain. In an attempt to identify endogenous brain substrates for calcineurin, kinetic analyses of the dephosphorylation of several well-characterized phosphoproteins purified from brain were performed. The proteins studied were:(More)
Studies on the interaction of calcineurin with its activator, calmodulin, showed that the 1:1 complex is the activated species. Concomitant with activation, a time-dependent deactivation of the phosphatase was observed. The process followed first order kinetics and was dependent on the presence of both Ca2+ and calmodulin. The deactivation rate constant at(More)
Studies were designed to determine if treatment with indomethacin influenced the growth of a transplantable, metastatic, rat mammary tumor. Female, Wistar-Furth inbred rats were fed either a standard chow diet or a semipurified diet containing 2, 5, 10, or 20% stripped corn oil. Indomethacin was given in drinking water, and rats consumed between 2.5 and 3.0(More)
A study of tumor incidence and tumor growth rates in 7,12-dimethylbenz(a)anthracene-treated female Sprague-Dawley rats fed different types and amounts of dietary fat indicates that the difference in tumor incidence may be a reflection of marked differences in the growth of neoplastic clones to a palpable size within the time frame of the study. In addition,(More)
Calcineurin, a Ca2+- and calmodulin-dependent phosphoprotein phosphatase, was dramatically activated by Ni2+ ions. Activation by Ni2+ was independent of calmodulin and was not reversed by high concentrations of chelators. With histone H1 as substrate, the Km's obtained with Ca2+ and Ni2+ were 2.2 and 4.2 microM, and the kcat's were 0.5 and 24.3 min-1,(More)
Because of the presence of bile-salt-activated lipase in cat milk, the dependence of the kitten on bile-salt-activated lipase is anticipated for milk fat absorption. To test this hypothesis, we initiated a feeding experiment comparing the growth rate of kittens fed with formula with those fed with formula and supplemented with purified human milk(More)
The two major forms of lung carcinoma, small cell lung carcinoma (SCLC) and non-small cell lung carcinoma (NSCLC), are clinically distinct, and are also differentiated by morphology and behavior in culture. SCLC cells have a greater metastatic potential than NSCLC cells in vivo, and exhibit a unique spherical morphology in culture due to their inability to(More)
Autophosphorylation plays an essential role in proteolytic activation of the type II calmodulin-dependent protein kinase (CaM kinase II). Limited proteolysis of CaM kinase II by trypsin, alpha-chymotrypsin, and Ca2+-stimulated neutral protease (calpain) yielded a catalytically active kinase fragment only when the holoenzyme was autophosphorylated prior to(More)
Modification of the type II calmodulin-dependent protein kinase by 5'-p-fluorosulfonylbenzoyl adenosine (FSBA) resulted in a time-dependent inactivation of the enzyme. The reaction followed pseudo-first-order kinetics and showed a nonlinear dependence on reagent concentration. The rate of inactivation was sensitive to Mg2+- and calmodulin-induced(More)