Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.21 (CPT)
 4,580 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

LPS, a bacterial endotoxin, induces the expression of many genes in macrophages. We report the cloning of a novel 3.3-kb cDNA that is a member of the thymidylate kinase family of genes. This clone, which we have designated TYKi, was obtained by screening a cDNA library prepared from RNA isolated from the murine cell line RAW264.7 after bacterial LPS treatment. TYKi is quite similar to all thymidylate kinases for which there are sequence data. It conserves two very important domains in these kinases, namely, the catalytic domain or P-loop and the nucleotide binding domain. After LPS exposure, the TYKi message appears at 2 h, peaks at 6 h, and declines at 8 h. LPS induction of TYKi is dependent on de novo protein synthesis. Increasing cytosolic cAMP with forskolin attenuates the LPS induction of TYKi. However, treatment with 8-(4-chlorophenylthio)-cAMP (CPT-cAMP) or dibutyryl-cAMP did not affect the LPS induction of TYKi. In contrast, activation of protein kinase C with phorbol ester augmented the LPS response, whereas inhibiting protein kinase C with 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7) suppressed the LPS response. Removing extracellular Ca2+ with EGTA inhibited LPS induction of TYKi, whereas increasing intracellular calcium with the calcium ionophore A23187 had little effect on the levels of the TYKi transcript. Inhibiting tyrosine kinase with genistein suppressed the induction of TYKi by LPS.
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PMID:A unique member of the thymidylate kinase family that is induced during macrophage activation. 775 51

Dihydropyridine-sensitive calcium channels can be strongly modulated by cAMP-dependent phosphorylation. This modulation takes the form of increased channel availability in cardiac myocytes (for review, see McDonald et al., 1994) and has been suggested to be essential for voltage-dependent facilitation in adrenal chromaffin cells (Artalejo et al., 1992) and skeletal muscle (Sculptoreanu et al., 1993b). To determine the role of cAMP-dependent phosphorylation on dihydropyridine-sensitive calcium channels in hippocampal neurons, we have used both single-channel and whole-cell recording techniques and have examined the effects of the membrane-permeable cAMP analog 8-(4-chlorophenylthio) (CPT)-cAMP and the protein kinase inhibitors 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) and N-[2-(p-bromocinnamyl-amino)ethyl]-5-isoquinolinesulfonamide (H-89). Hippocampal neurons contain two kinds of dihydropyridine-sensitive calcium channel activity: Ls and Lp (Kavalali and Plummer, 1994). The Ls channel closely resembles the cardiac L-type channel, whereas the Lp channel shows a novel low-voltage form of voltage-dependent potentiation (). 8-CPT-cAMP increased the availability of both the Ls and Lp channels and caused a parallel increase in Lp channel reopenings at the repolarization potential that result from voltage-dependent potentiation. This effect was completely blocked by the broad spectrum kinase inhibitor H-7 and by the protein kinase A-specific inhibitor H-89. The two inhibitors, however, did not disrupt baseline potentiation of the Lp channel, suggesting that cAMP-dependent protein kinase activity can enhance Ls and Lp channel activity but is not required for voltage-dependent potentiation in hippocampal neurons.
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PMID:cAMP-dependent enhancement of dihydropyridine-sensitive calcium channel availability in hippocampal neurons. 920 18