Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this work, we demonstrate that the phosphatidylinositol 3,4,5-trisphosphate-binding protein JFC1 is an ATP-binding protein with magnesium-dependent ATPase activity. We show that JFC1 specifically binds to the ATP analog 8-azido-[alpha-(32)P]ATP. The affinity of JFC1 for [alpha-(32)P]ATP was 10x greater than its affinity for [alpha-(32)P]ADP; the protein did not appear to bind to [alpha-(32)P]GTP. JFC1 hydrolyzed [alpha-(32)P]ATP in a Mg(2+)-dependent manner. JFC1, which also hydrolyzed dATP, has a relatively high affinity for ATP, with a K(M) value of 58 microM, and a k(cat) value of 2.27 per min. The predicted amino acid sequence of JFC1 denotes a putative nucleotide-binding site similar to those in the GHKL ATPase/kinase superfamily. However, a truncation of JFC1 that contains boxes G2 and G3 but not boxes N and G1 of the Bergerat-binding site showed residual ATPase activity. Secondly, the antitumor ATP-mimetic agent geldanamycin, which inhibits the ATPase activity of Hsp-90, did not affect JFC1 ATPase. Therefore, the characteristics of the ATP-binding site of JFC1 are unique. Phosphatidylinositol 3,4,5-trisphosphate, a high-affinity ligand of JFC1 did not affect its ATPase kinetics parameters, suggesting that the phosphoinositide have a different role in JFC1 function.
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PMID:Characterization of the nucleotide-binding capacity and the ATPase activity of the PIP3-binding protein JFC1. 1155 74

The human promoter region of JFC1, a phosphatidylinositol 3,4,5-trisphosphate binding ATPase, was isolated by amplification of a 549 bp region upstream of the jfc1 gene by the use of a double-PCR system. By primer extension analysis we mapped the transcription initiation site at nucleotide -321 relative to the translation start site. Putative regulatory elements were identified in the jfc1 TATA-less promoter, including three consensus sites for nuclear factor-kappaB (NF-kappaB). We analysed the three putative NF-kappaB binding sites by gel retardation and supershift assays. Each of the putative NF-kappaB sites interacted specifically with recombinant NF-kappaB p50, and the complexes co-migrated with those formed by the NF-kappaB consensus sequence and p50. An antibody to p50 generated a supershifted complex for these NF-kappaB sites. These sites formed specific complexes with nuclear proteins from tumour necrosis factor alpha (TNFalpha)-treated WEHI 231 cells, which were supershifted with antibodies against p50 and p65. The jfc1 promoter was transcriptionally active in various cell lines, as determined by luciferase reporter assays following transfection with a jfc1 promoter luciferase vector. Co-transfection with NF-kappaB expression vectors or stimulation with TNFalpha resulted in significant transactivation of the jfc1 promoter construct, although transactivation of a mutated jfc1 promoter was negligible. The expression of a dominant negative IkappaB (inhibitor kappaB) decreased basal jfc1 promoter activity. The cell lines PC-3, LNCaP and DU-145, but not Epstein-Barr virus-transformed lymphocytes, showed a dramatic increase in the expression of JFC1 after treatment with TNFalpha, suggesting that transcriptional activation of JFC1 by the TNFalpha/NF-kappaB pathway is significant in prostate carcinoma cell lines.
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PMID:JFC1 is transcriptionally activated by nuclear factor-kappaB and up-regulated by tumour necrosis factor alpha in prostate carcinoma cells. 1213 62