Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.16 (calcineurin)
 17,112 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Okadaic acid, a protein phosphatase inhibitor, is a strong tumor promoter which activates protein phosphorylation. Because another activator of protein phosphorylation, phorbol esters, stimulates hematopoietic differentiation, we sought to determine whether okadaic acid could also induce the differentiation of the human leukemic cell line U937. Differentiation was assessed by measuring changes in the following: mRNA levels, cell growth, morphology, cell surface markers, and the ability to induce superoxide. We found that okadaic acid treatment of U937 cells induces immediate increases in total cellular levels of both c-jun and c-fos mRNAs. Nuclear run-on experiments demonstrate that initial increases are secondary to increases in transcription, whereas latter changes may be secondary to mRNA stabilization. Like phorbol esters, okadaic acid treatment also activates AP-1 enhancer activity and induces the phosphorylation of c-Jun protein. Approximately 6-12 hours after treatment with okadaic acid, mRNA levels of c-myc, p34cdc2, and p58GTA, two cell cycle regulated protein kinases, decrease. Okadaic acid inhibits the growth of U937 cells, induces changes in nuclear morphology, stimulates increases in Mac-1 and Leu 11 surface antigens, and induces these cells to produce superoxide. These changes, taken together, suggest that U937 cells have been induced by okadaic acid to differentiate towards a more mature cell type.
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PMID:Induction of differentiation and c-jun expression in human leukemic cells by okadaic acid, an inhibitor of protein phosphatases. 131 24

Members of the Hedgehog (Hh) family of signaling proteins are powerful regulators of developmental processes in many organisms and have been implicated in many human disease states. Here we report the results of a genome-wide RNA interference screen in Drosophila melanogaster cells for new components of the Hh signaling pathway. The screen identified hundreds of potential new regulators of Hh signaling, including many large protein complexes with pleiotropic effects, such as the coat protein complex I (COPI) complex, the ribosome and the proteasome. We identified the multimeric protein phosphatase 2A (PP2A) and two new kinases, the D. melanogaster orthologs of the vertebrate PITSLRE and cyclin-dependent kinase-9 (CDK9) kinases, as Hh regulators. We also identified a large group of constitutive and alternative splicing factors, two nucleoporins involved in mRNA export and several RNA-regulatory proteins as potent regulators of Hh signal transduction, indicating that splicing regulation and mRNA transport have a previously unrecognized role in Hh signaling. Finally, we showed that several of these genes have conserved roles in mammalian Hh signaling.
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PMID:A genome-wide RNA interference screen in Drosophila melanogaster cells for new components of the Hh signaling pathway. 1631 96