Charles M. Schworer

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Fractional volumes of lysosomal-vacuolar elements and long lived protein degradation were quantitatively correlated in rat livers perfused in the single pass mode with varying levels of plasma amino acids. Volumes were determined stereologically; degradation was measured in a second stage cyclic perfusion from the linear accumulation of valine in the(More)
The Ca2+(calmodulin (CaM))-dependent protein kinase II, purified from either rabbit liver or rat brain, was preincubated under conditions that are known to promote its autophosphorylation. When kinase activity was assayed after this preincubation, it was observed that excess EGTA could block no more than 40-60% of the total Ca2+- and CaM-dependent activity(More)
Two novel isoforms of the Ca2+/calmodulin-dependent protein kinase II delta subunit were detected in rat aorta. Identification of the subunits was based on two independent lines of evidence, i.e. detection by immunoblotting of differently sized delta subunits and DNA sequence analysis of partial cDNA clones of the kinase. Cytosolic extracts from rat brain,(More)
Amino acid deprivation and glucagon are both potent inducers of autography and proteolysis in liver. Because glucagon enhanced the metabolic utilization of some amino acids, the catabolic response to both of these stimuli could be achieved by a lowering of intracellular amino acid pools. Alternatively, glucagon could act independently of amino acids. To(More)
Regulatory mechanisms of rat brain Ca2+/calmodulin-dependent protein kinase II (CaM-kinase II) were probed using a synthetic peptide (CaMK-(281-309] corresponding to residues 281-309 (alpha-subunit) which contained the calmodulin (CaM)-binding and inhibitory domains and also the initial autophosphorylation site (Thr286). Kinetic analyses indicated that(More)
Incubation of purified rat brain Ca2+/calmodulin-dependent protein kinase II for 2 min in the presence of Ca2+, calmodulin (CaM), Mg2+, and ATP converted the kinase from a completely Ca2+-dependent kinase to a substantially Ca2+-independent form with little loss of total activity. Subsequent addition of EGTA to the autophosphorylation reaction enhanced(More)
Activation of Ca2+/calmodulin (CaM)-dependent protein kinase II (CaM kinase II) and development of the Ca2+/CaM-independent (autonomous) form of the kinase was investigated in cultured vascular smooth muscle (VSM) cells. Within 15 s of ionomycin (1 microM) exposure 52.7 +/- 4.4% of the kinase became autonomous, a response that was partially maintained for(More)
Calcium/calmodulin (CaM)-dependent protein kinase II (CaM-kinase II) contained within the postsynaptic density (PSD) was shown to become partially Ca2+-independent following initial activation by Ca2+/CaM. Generation of this Ca2+-independent species was dependent upon autophosphorylation of both subunits of the enzyme in the presence of Mg2+/ATP/Ca2+/CaM(More)
Exposure of cultured rat aortic vascular smooth muscle (VSM) cells to the Ca2+ ionophore ionomycin produced an increase in extracellular signal-regulated kinase 1/2 (ERK1/2) activity that was maximal between 2 and 5 minutes but then declined to basal values within 20 minutes of stimulation. Elevation of [Ca2+]i in VSM cells leads to an even more rapid(More)
We show that phenylalanine is able to control the extent of activation and, as a result, the catalytic activity of rat liver phenylalanine hydroxylase in vivo, in perfused liver, and in vitro. Both phosphorylated and unphosphorylated enzyme activities are controlled by phenylalanine activation and, overall, this mechanism appears to be a major means of(More)