Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cDNA for acid beta-glucosidase, the Gaucher disease enzyme, was overexpressed in a variety of mammalian cells and in Sf9 insect cells. Whether overexpressed from the MFG-GC retrovirus or the tetracycline transactivator system, there was a large discrepancy between the amounts of mRNA (>750-fold) and acid beta-glucosidase protein (approximately 6- to 14-fold) produced in mammalian cells. This was not observed in Sf9 insect cells. Quantitative evaluation of translation of this mRNA in intact mammalian cells indicated a 55- to 135-fold inefficiency in cell lines compared to normal human skin fibroblasts. In vitro translation efficiency with acid beta-glucosidase mRNAs from overexpressing mammalian or insect cells was similar to that from normal human fibroblasts. A cytoplasmic, heat labile protein was suggested as inhibitory to in vitro translation of these RNAs. North-Western blots and cytoplasmic depletion experiments showed this to be an 80-kDa cytoplasmic mRNA-binding protein that recognized acid beta-glucosidase coding sequences. The cytoplasmic protein was not detected in insect cells. These results implicate acid beta-glucosidase coding sequences and a heat labile cytoplasmic protein in modulating the translation of overexpressed mRNA in transgenic cell lines.
Mol Genet Metab 1998 Jun
PMID:Translational inefficiency of acid beta-glucosidase mRNA in transgenic mammalian cells. 970 33

The mechanisms by which transforming growth factor beta (TGF-beta) and related ligands regulate transcription remain poorly understood. The winged-helix (WH) transcription factor fork head activin signal transducer 1 (FAST-1) was identified as a mediator of activin signaling in Xenopus embryos (X. Chen, M. J. Rubock, and M. Whitman, Nature 383:691-696, 1996). We have cloned a novel WH gene from the mouse which shares many properties with FAST-1. We find that this gene, which we call FAST-2, is able to mediate transcriptional activation by TGF-beta. FAST-2 also interacts directly with Smad2, a cytoplasmic protein which is translocated to the nucleus in response to TGF-beta, and forms a multimeric complex with Smad2 and Smad4 on the activin response element, a high-affinity binding site for FAST-1. Analysis of the sequences of FAST-1 and FAST-2 reveals substantial protein sequence divergence compared to known vertebrate orthologs in the WH family. This suggests that FAST-2 represents a new WH gene related to FAST-1, which functions to mediate TGF-beta signals in mammals. We have also examined the structure of the FAST-2 gene and find that it overlaps with a kinesin motor protein gene. The genes are transcribed in opposite orientations, and their transcripts overlap in the 3' untranslated region.
Mol Cell Biol 1999 Jan
PMID:FAST-2 is a mammalian winged-helix protein which mediates transforming growth factor beta signals. 985 66

Fluoride is an acknowledged bone anabolic agent. Nevertheless, a narrow therapeutic window and the adverse effects at higher therapeutic doses prevent broad clinical application of fluoride for treatment of diseases of bone loss, such as osteoporosis. The cellular and molecular mechanisms of fluoride action are poorly understood. recent advances in the elucidation of signal transduction pathways induced by fluoride in osteoblastic cells are reviewed. Fluoride and traces of aluminum form a complex, fluoroaluminate, which stimulates cellular heterotrimeric G proteins. Such complex can form in food, drinking water and in the organism after administration of sodium fluoride. Fluoroaluminate crosses the cell membrane and directly binds to the membrane-associated inactive G alpha protein subunits. Within the G alpha subunit, fluoroaluminate occupies the position next to GDP. The resulting G alpha-GDP-AlF4- complex assumes an active state conformation, which resembles that of G alpha-GTP complex. Under physiological conditions, G alpha-GTP complex is formed upon activation of seven transmembrane receptors that couple to heterotrimeric G proteins. Both fluoroaluminate-activated and receptor-activated G alpha subunits are capable of transmitting intracellular signals that lead to cellular responses. In bone-forming cells osteoblasts, fluoroaluminate stimulates pertussis toxin-sensitive G alpha i proteins. G alpha i activation leads to the reduction in cAMP (cyclic adenosine monophosphate) levels and to the activation of mitogen activated protein kinases, Erks (extracellular signal-regulated kinases) and p70 S6 kinase. These kinases are involved in the regulation of gene transcription and protein syntheses. Fluoroaluminate also stimulates pertussis toxin-insensitive proteins. Pertussis toxin-insensitive G proteins, most likely from G alpha 12 class, cause the activation of several cytoplasmic protein tyrosine kinases [Src, Pyk2 (proline-rich tyrosine kinase 2), and Fak (focal adhesion kinase)]. Activation of Erks can lead to osteoblast proliferation and differentiation, while activation of Src, Pyk2 and Fak can modulate the adhesion properties of osteoblasts. Osteoblast adhesion may, in turn, influence differentiation, migration, and apoptosis of these cells. The susceptibility of osteoblasts to fluoroaluminate can be achieved by their specific cellular context and by the rigidity of the surrounding bone tissue. In particular, higher levels of G alpha i proteins and of certain focal adhesion proteins are expressed by osteoblastic rather than by fibroblastic cells. The rigidity of adhesion substratum of osteoblasts may signal on its own and potentiate the signaling by fluoroaluminate. The information on mechanisms of intracellular signaling by fluoroaluminate can be utilized to identify a fluoroaluminate mimic, a drug that exhibits anabolic action on bone with a broader therapeutic range and less adverse effects than fluoride.
Int J Mol Med 1999 Feb
PMID:Heterotrimeric G proteins as fluoride targets in bone (review). 991 18

A mutation in NMD3 was found to be lethal in the absence of XRN1, which encodes the major cytoplasmic exoribonuclease responsible for mRNA turnover. Molecular genetic analysis of NMD3 revealed that it is an essential gene required for stable 60S ribosomal subunits. Cells bearing a temperature-sensitive allele of NMD3 had decreased levels of 60S subunits at the nonpermissive temperature which resulted in the formation of half-mer polysomes. Pulse-chase analysis of rRNA biogenesis indicated that 25S rRNA was made and processed with kinetics similar to wild-type kinetics. However, the mature RNA was rapidly degraded, with a half-life of 4 min. Nmd3p fractionated as a cytoplasmic protein and sedimented in the position of free 60S subunits in sucrose gradients. These results suggest that Nmd3p is a cytoplasmic factor required for a late cytoplasmic assembly step of the 60S subunit but is not a ribosomal protein. Putative orthologs of Nmd3p exist in Drosophila, in nematodes, and in archaebacteria but not in eubacteria. The Nmd3 protein sequence does not contain readily recognizable motifs of known function. However, these proteins all have an amino-terminal domain containing four repeats of Cx2C, reminiscent of zinc-binding proteins, implicated in nucleic acid binding or protein oligomerization.
Mol Cell Biol 1999 Mar
PMID:NMD3 encodes an essential cytoplasmic protein required for stable 60S ribosomal subunits in Saccharomyces cerevisiae. 1002 25

The Madin Darby bovine kidney (MDBK) cell line was used to investigate the mechanisms underlying the cAMP regulation of insulin-like growth factor binding protein-3 (IGFBP-3) gene expression. Treatment of confluent monolayers either with forskolin or cAMP produced a 60- to 75-fold induction of IGFBP-3 mRNA and protein levels. This effect did not require new protein synthesis as inhibition of translation by cycloheximide actually caused a 2-fold increase in the cAMP induction. The rates of IGFBP-3 gene transcription, assessed by nuclear run-on assays, increased approximately 15-fold in cells exposed to cAMP. In addition, the half-life of the IGFBP-3 mRNA transcript was increased approximately 3-fold in the presence of cAMP. Gel mobility shift and competition experiments revealed the specific binding of an approximately 42-kDa cytoplasmic protein factor to the 3'-untranslated region (3'-UTR) of the IGFBP-3 mRNA. A 21-nucleotide uridine-rich segment that contained no AUUUA motif was sufficient for the specific binding. The binding activity of this protein was reduced after cAMP treatment but was increased by phosphatase treatment. In conclusion, the cAMP induction of IGFBP-3 mRNA in MDBK cells occurred at both the transcriptional and posttranscriptional levels. The IGFBP-3 mRNA stabilization in MDBK cells probably involved the phosphorylation of a member of the family of U-rich region mRNA-binding proteins and is the first reported member whose RNA-binding activity is reduced by cAMP.
Mol Endocrinol 1999 Mar
PMID:Transcriptional and posttranscriptional regulation of insulin-like growth factor binding protein-3 by cyclic adenosine 3',5'-monophosphate: messenger RNA stabilization is accompanied by decreased binding of a 42-kDa protein to a uridine-rich domain in the 3'-untranslated region. 1007 6

A cytoplasmic protein tyrosine phosphatase (PTPase) designated as striatal enriched phosphatase with a molecular weight of 46 kDa (STEP46) is highly expressed in striatal neurons with dopamine D1-receptors. To examine the hypothesis that STEP46 is involved in the neuronal functions modulated by the cyclic adenosine 3', 5'-monophosphate (cAMP)-signaling system, we introduced the complementary DNA of STEP46 into the pheochromocytoma cell line PC12, which exhibits neuronal differentiation characterized by neurite outgrowth in response to cAMP and nerve growth factor stimulation, and we established subclonal cell lines that constitutively overexpress STEP46 protein with PTPase activity. The subclones expressing STEP46 showed increased neurite outgrowth during differentiation induced by a cAMP analogue (dibutyryl cAMP). The positive regulatory role of STEP46 in the cAMP-induced neuronal differentiation of PC12 cells indicates that STEP46 may play a role in neuronal processes modulated by the cAMP-signaling cascade as a PTPase.
Brain Res Mol Brain Res 1999 Apr 06
PMID:Overexpression of striatal enriched phosphatase (STEP) promotes the neurite outgrowth induced by a cAMP analogue in PC12 cells. 1010 Dec 26

We have previously shown that human munc13 (hmunc13) is up-regulated by hyperglycemia under in vitro conditions in human mesangial cell cultures. The purpose of the present study was to determine the cellular function of hmunc13. To do this, we have investigated the subcellular localization of hmunc13 in a transiently transfected renal cell line, opossum kidney cells. We have found that hmunc13 is a cytoplasmic protein and is translocated to the Golgi apparatus after phorbol ester stimulation. In addition, cells transfected with hmunc13 demonstrate apoptosis after treatment with phorbol ester, but cells transfected with an hmunc13 deletion mutant in which the diacylglycerol (C1) binding domain is absent exhibit no change in intracellular distribution and no induction of apoptosis in the presence of phorbol ester stimulation. We conclude that both the diacylglycerol-induced translocation and the apoptosis represent functional activity of hmunc13. We have also demonstrated that munc13-1 and munc13-2 are localized mainly to cortical epithelial cells in rat kidney and both are overexpressed under conditions of hyperglycemia in a streptozotocin-treated diabetic rat model. Taken together, our data suggest that hmunc13 serves as a diacylglycerol-activated, PKC-independent signaling pathway capable of inducing apoptosis and that this pathway may contribute to the renal cell complications of hyperglycemia.
Mol Biol Cell 1999 May
PMID:Human munc13 is a diacylglycerol receptor that induces apoptosis and may contribute to renal cell injury in hyperglycemia. 1023 66

The chaperone function of the mammalian 70-kDa heat shock proteins Hsc70 and Hsp70 is modulated by physical interactions with four previously identified chaperone cofactors: Hsp40, BAG-1, the Hsc70-interacting protein Hip, and the Hsc70-Hsp90-organizing protein Hop. Hip and Hop interact with Hsc70 via a tetratricopeptide repeat domain. In a search for additional tetratricopeptide repeat-containing proteins, we have identified a novel 35-kDa cytoplasmic protein, carboxyl terminus of Hsc70-interacting protein (CHIP). CHIP is highly expressed in adult striated muscle in vivo and is expressed broadly in vitro in tissue culture. Hsc70 and Hsp70 were identified as potential interaction partners for this protein in a yeast two-hybrid screen. In vitro binding assays demonstrated direct interactions between CHIP and both Hsc70 and Hsp70, and complexes containing CHIP and Hsc70 were identified in immunoprecipitates of human skeletal muscle cells in vivo. Using glutathione S-transferase fusions, we found that CHIP interacted with the carboxy-terminal residues 540 to 650 of Hsc70, whereas Hsc70 interacted with the amino-terminal residues 1 to 197 (containing the tetratricopeptide domain and an adjacent charged domain) of CHIP. Recombinant CHIP inhibited Hsp40-stimulated ATPase activity of Hsc70 and Hsp70, suggesting that CHIP blocks the forward reaction of the Hsc70-Hsp70 substrate-binding cycle. Consistent with this observation, both luciferase refolding and substrate binding in the presence of Hsp40 and Hsp70 were inhibited by CHIP. Taken together, these results indicate that CHIP decreases net ATPase activity and reduces chaperone efficiency, and they implicate CHIP in the negative regulation of the forward reaction of the Hsc70-Hsp70 substrate-binding cycle.
Mol Cell Biol 1999 Jun
PMID:Identification of CHIP, a novel tetratricopeptide repeat-containing protein that interacts with heat shock proteins and negatively regulates chaperone functions. 1033 Jan 92

Integrin-linked kinase (ILK) is a recently identified cytoplasmic protein serine/threonine kinase implicated in integrin-, growth factor- and Wnt-signaling pathways. It contains several structurally conserved motifs including ankyrin repeats, pleckstrin-homology (PH) domain and protein kinase catalytic domain that are critical for signal transduction. Recent studies have documented that ILK plays important roles in bi-directional ( and ) transmembrane signaling pathways via integrins and other proteins, leading to regulation of cell adhesion, growth, survival, extracellular matrix deposition and potentially differentiation. Furthermore, ILK is implicated in tumorigenesis and ILK appears to be a useful diagnostic marker of certain human tumors. The identification of novel ILK-associated proteins will provide a better understanding of how ILK functions in intracellular signal transduction cascades and tumorigenesis.
Int J Mol Med 1999 Jun
PMID:Integrin-linked kinase and associated proteins (review). 1034 Dec 84

Activation of ERK/MAPK is a key event downstream of RAS. The duration, extent, and timing of MAPK activity is integral to signal specificity. Consequently, inactivation of MAPK by phosphatases has emerged as a critical element in the precise control of signal output. We have cloned and characterized a novel cytoplasmic protein tyrosine phosphatase, PTP-ER, which is related to mammalian PCPTP1, LC-PTP/HePTP, and STEP tyrosine phosphatases. PTP-ER mutants produce extra R7 cells and enhance activated Ras1 signaling. Ectopic expression of PTP-ER dramatically inhibits RAS1/MAPK signaling. PTP-ER binds to and inactivates Drosophila ERK/MAPK; however, it is unable to dephosphorylate and downregulate Drosophila MAPKSevenmaker. Resistance to PTP-ER activity partially accounts for the Sevenmaker mutant phenotype.
Mol Cell 1999 Jun
PMID:PTP-ER, a novel tyrosine phosphatase, functions downstream of Ras1 to downregulate MAP kinase during Drosophila eye development. 1039 62


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