Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.2 (focal adhesion kinase)
 44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using the 3T3-F442A preadipocyte line as a model of GH-dependent differentiation, early changes in the DNA-binding affinity of transcription factors in response to GH addition were investigated. Addition of 50 ng/ml human GH to cells in chemically defined medium led to a rapid increase in binding activity of activator protein 1 (AP-1) and CCAAT enhancer-binding protein (C/EBP), which was significant at 30 min and reached maximal induction by 2 h (3-fold for AP-1, 2.5-fold for C/EBP). Induction in AP-1 DNA binding correlates with a concomitant GH trans-activation of c-jun and c-fos genes described previously. Using specific antibodies in electrophoretic mobility shift assays and Western blots, it was shown that the increase in activity of C/EBP is the result of an increase in synthesis of two alternatively translated forms of C/EBP beta: 40-C/EBP beta and 23-C/EBP beta. This increase in protein was not accompanied by alteration in mRNA level and could be blocked by a Janus kinase 2 tyrosine kinase inhibitor and a C kinase inhibitor at concentrations shown to inhibit GH-dependent activation of microtubule-associated protein (MAP) kinases. Concomitant with the translationally activated increase in C/EBP beta, a GH-dependent increase was observed in C/EBP delta transcription. This was accompanied by an increase in mRNA for C/EBP delta, which was superinduced by cycloheximide and, unlike the increase in C/EBP beta protein, was not observed with insulin. Thus GH exerts its effects on C/EBP isoforms at two levels: transcriptional activation of C/EBP delta and translational activation of C/EBP beta. It is proposed that GH-dependent phosphorylation results in the efficient translation of 40-C/EBP beta and 23-C/EBP beta (the mouse homolog of the inhibitor liver-enriched inhibitory protein), and that together with the induction of C/EBP delta, these may be involved in initiating the adipocyte differentiation program.
Mol Endocrinol 1995 Jan
PMID:Early responses of trans-activating factors to growth hormone in preadipocytes: differential regulation of CCAAT enhancer-binding protein-beta (C/EBP beta) and C/EBP delta. 776 Aug 44

The human proto-oncogene HCK encodes two versions of a protein-tyrosine kinase, with molecular weights of 59,000 (p59hck) and 61,000 (p61hck). The two proteins arise from a single mRNA by alternative initiations of translation. In this study, we explored the functions of these proteins by determining their locations within cells and by characterizing lipid modifications required for the proteins to reach those locations. We found that p59hck is entirely associated with cellular membranes, including the organelles known as caveolae; in contrast, only a portion of p61hck is situated on membranes, and none is detectable in preparations of caveolae. These distinctions can be attributed to differential modification of the two HCK proteins with fatty acids. Both proteins are at least in part myristoylated, p59hck more so than p61hck. In addition, however, p59hck is palmitoylated on cysteine 3 in the protein. Palmitoylation of the protein requires prior myristoylation and, in turn, is required for targeting to caveolae. These findings are in accord with recent reports for other members of the SRC family of protein-tyrosine kinases. Taken together, the results suggest that HCK and several of its relatives may participate in the functions of caveolae, which apparently include the transduction of signals across the plasma membrane to the interior of the cell.
Mol Cell Biol 1995 Jul
PMID:Myristoylation and differential palmitoylation of the HCK protein-tyrosine kinases govern their attachment to membranes and association with caveolae. 779 57

BRK cell lines that stably express adenovirus E1A and a murine temperature-sensitive p53 undergo apoptosis when p53 assumes the wild-type conformation. Expression of the E1B 19,000-molecular-weight (19K) protein rescues cells from this p53-mediated apoptosis and diverts cells to a growth-arrested state. As p53 likely functions as a tumor suppressor by regulating transcription, the ability of the E1B 19K protein to regulate p53-mediated transactivation and transcriptional repression was investigated. In promoter-reporter assays the E1B 19K did not block p53-mediated transactivation but did alleviate p53-mediated transcriptional repression. E1B 19K expression permitted efficient transcriptional activation of the p21/WAF-1/cip-1 mRNA by p53, consistent with maintenance of the growth arrest function of p53. The E1B 19K protein is thereby unique among DNA virus-transforming proteins that target p53 for inactivation in that it selectively modulates the transcriptional properties of p53. The E1B 19K protein also rescued cells from apoptosis induced by inhibitors of transcription and protein synthesis. This suggests that cell death may result from the inhibition of expression of survival factors which function to maintain cell viability. p53 may induce apoptosis through generalized transcriptional repression. In turn, the E1B 19K protein may prevent p53-mediated apoptosis by alleviating p53-mediated transcriptional repression.
Mol Cell Biol 1995 Feb
PMID:Modulation of p53-mediated transcriptional repression and apoptosis by the adenovirus E1B 19K protein. 782 21

Mutations in the gene for Bruton's tyrosine kinase (Btk) are responsible for X-linked agammaglobulinemia (XLA). Thus far, mutations in this gene have been identified based on alterations in Southern or Northern blot analysis or cDNA sequence. To permit detection of mutations in genomic DNA, we designed PCR primers to flank each of the 19 exons of Btk with splice sites. Two overlapping PCR products were employed for exons longer than 230 base pairs. Single strand conformation polymorphism (SSCP) analysis was used to screen PCR products from 30 unrelated families presumed to carry a Btk mutation. It was possible to amplify DNA in every reaction from every patient, indicating that large deletions in Btk are uncommon. Twenty three different mutations were found in 25 unrelated families, including one family in whom DNA was available from a carrier but not an affected patient. Seven mutations were single base pair substitutions resulting in premature stop codons scattered throughout the gene. Small insertions or deletions causing frameshifts and secondary premature stop codons constituted an additional seven mutations. One patient had a point mutation in the start codon and one patient had a mutation in a splice donor site. Point mutations resulting in amino acid substitutions were seen in nine patients. Northern blot analysis of RNA from three patients with premature stop codons showed an absence of Btk transcript whereas four patients with amino acid substitutions had normal amounts of transcript of normal size. These studies document the considerable variability in the Btk mutations causing XLA and they demonstrate an approach that will be useful for carrier detection as well as mutation identification.
Hum Mol Genet 1994 Oct
PMID:Screening of genomic DNA to identify mutations in the gene for Bruton's tyrosine kinase. 784 97

The defective gene responsible for the recessively inherited immunodeficiency X-linked agammaglobulinemia (XLA) has been shown to encode a cytoplasmic protein tyrosine kinase of the Src family designated Btk (Bruton's tyrosine kinase). To facilitate the search for germline mutations of the Btk gene, we have characterized its genomic structure. Eighteen introns were positioned within the approximately 37 kb gene. Each of the exon/intron boundaries were defined and sequenced, and all but two conform to consensus sequences. We have utilized the genomic organization of Btk and the intervening sequence data to design an assay for amplifying each of the 19 exons from XLA patient DNA for single strand conformation polymorphism (SSCP) analysis. By using this method we have identified mutations in 12 of 14 unrelated affected males: seven different base substitutions and two small deletions. Two of the mutations described in exon 15 of the kinase domain were found in more than one patient and may represent a mutation hot spot. Exon scanning has proven to be a valuable method for identifying the patient mutations in genomic DNA without the use of cDNA. The mutations are easily confirmed with direct sequencing of the amplified exons. This approach will greatly benefit XLA family studies involving carrier detection and prenatal diagnosis. In addition, the mutations identified may reveal residues involved in the specific protein interactions necessary in the B-cell developmental pathway, of which Btk is an integral component.
Hum Mol Genet 1994 Oct
PMID:Genomic organization of the Btk gene and exon scanning for mutations in patients with X-linked agammaglobulinemia. 788 Mar 20

The human growth hormone (hGH) induced a marked reduction in the number of human growth hormone receptors (hGHR) within 60 min, as assessed by immunoblotting of the crude membrane fraction from human IM-9 cells, without an increase in soluble forms of hGHR. The disappearance of hGH-induced hGHR was markedly inhibited by reagents that raise the internal pH of acidic organella and partially by protease inhibitors. These results suggest that hGH stimulation results in degradation of internalized hGHRs, where proteases in acidic compartments such as lysosomes may be involved. The relationship between the hGH concentration and the number of residual cell surface hGHRs 60 min after hGH stimulation yielded a curve with an inverted bell shape showing maximum internalization at 10 nM hGH. A similar relationship was shown in the hGHR degradation. The fact that the ligands in excess gave reduced internalization and degradation supports the idea that dimerization of hGHRs on the cell surface through the bivalent ligand hGH is required for their internalization and subsequent degradation. Following hGH stimulation, several hGHR-associated proteins including JAK2 were phosphorylated. These phosphorylations were inhibited by pretreatment with a protein kinase inhibitor, staurosporine. The hGHR internalization, however, was not markedly affected by the inhibitor. In contrast, the staurosporine inhibited the degradation of hGHR in a dose-dependent manner. These results suggest that staurosporine-sensitive phosphorylation is not required for the hGHR internalization, but the phosphorylation is involved in the degradation of hGHR.
Mol Cell Endocrinol 1994 Dec
PMID:Ligand-induced internalization and phosphorylation-dependent degradation of growth hormone receptor in human IM-9 cells. 789 16

Many natural populations fluctuate widely in population size. This is predicted to reduce effective population size, genetic variation, and reproductive fitness, and to increase inbreeding. The effects of fluctuating population size were examined in small populations of Drosophila melanogaster of the same average size, but maintained using either fluctuating (FPS) or equal (EPS) population sizes. FPS lines were maintained using seven pairs and one pair in alternate generations, and EPS lines with four pairs per generation. Ten replicates of each treatment were maintained. After eight generations, FPS had a higher inbreeding coefficient than EPS (0.60 vs. 0.38), a lower average allozyme heterozygosity (0.068 vs. 0.131), and a much lower relative fitness (0.03 vs. 0.25). Estimates of effective population sizes for FPS and EPS were 3.8 and 7.9 from pedigree inbreeding, and 4.9 vs. 7.1 from changes in average heterozygosities, as compared to theoretical expectations of 3.3 vs. 8.0. Results were generally in accordance with theoretical predictions. Management strategies for populations of rare and endangered species should aim to minimize population fluctuations over generations.
Mol Ecol 1994 Aug
PMID:Modelling problems in conservation genetics using Drosophila: consequences of fluctuating population sizes. 792 63

The erythropoietin (EPO) receptor and the interleukin-2 (IL-2) receptor beta-chain subunit are members of the cytokine receptor superfamily. They have conserved primary amino acid sequences in their cytoplasmic domains and activate phosphorylation of common substrates, suggesting common biochemical signaling mechanisms. We have generated a cell line, CTLL-EPO-R, that contains functional cell surface receptors for both EPO and IL-2. CTLL-EPO-R cells demonstrated similar growth kinetics in EPO and IL-2. Stimulation with EPO resulted in the rapid, dose-dependent tyrosine phosphorylation of JAK2. In contrast, stimulation with IL-2 or the related cytokine IL-4 resulted in the rapid, dose-dependent tyrosine phosphorylation of JAK1 and an additional 116-kDa protein. This 116-kDa protein was itself immunoreactive with a polyclonal antiserum raised against JAK2 and appears to be a novel member of the JAK kinase family. Immune complex kinase assays confirmed that IL-2 and IL-4 activated JAK1 and EPO activated JAK2. These results demonstrate that multiple biochemical pathways are capable of conferring a mitogenic signal in CTLL-EPO-R cells and that the EPO and IL-2 receptors interact with distinct JAK kinase family members within the same cellular background.
Mol Cell Biol 1994 Oct
PMID:Erythropoietin and interleukin-2 activate distinct JAK kinase family members. 793 73

A gene for a novel, putative cytoplasmic tyrosine kinase, TXK has been isolated from a human peripheral blood cDNA library. The complete nucleotide sequence of the cDNA indicates that it is related most closely to EMT, a tyrosine kinase of T cells and to the B-cell tyrosine kinase Btk, which is mutated in X-linked agammaglobulinemia (XLA) in humans and X-linked immunodeficiency disease (XID) in mouse. TXK, like BTK, is a member of the Tec sub-family of Src-type (non-receptor) tyrosine kinases. Like similar Tec sub-family members, and unlike the other Src kinases, TXK lacks both the N-terminal myristylation signal and the C-terminal regulatory tyrosine. TXK expression is detected primarily in T cells and some myeloid cell lines but not in a number of other cell types. TXK shares 60% amino acid homology with EMT and 57% with BTK over the SH3, SH2 (Src-homology) and catalytic domains but unlike BTK, EMT and tec, it lacks Gap 1 homology and steroid hormone receptor homology in the N-terminal region. Genomic clones containing TXK have been isolated and hybridize to chromosome position 4p12.
Hum Mol Genet 1994 Jun
PMID:TXK, a novel human tyrosine kinase expressed in T cells shares sequence identity with Tec family kinases and maps to 4p12. 795 Dec 33

The high-affinity receptor for granulocyte-macrophage colony-stimulating factor (GM-CSF) consists of a unique alpha chain and a beta c subunit that is shared with the receptors for interleukin-3 (IL-3) and IL-5. Two regions of the beta c chain have been defined; these include a membrane-proximal region of the cytoplasmic domain that is required for mitogenesis and a membrane-distal region that is required for activation of Ras, Raf-1, mitogen-activated protein kinase, and S6 kinase. Recent studies have implicated the cytoplasmic protein tyrosine kinase JAK2 in signalling through a number of the cytokine receptors, including the IL-3 and erythropoietin receptors. In the studies described here, we demonstrate that GM-CSF stimulation of cells induces the tyrosine phosphorylation of JAK2 and activates its in vitro kinase activity. Mutational analysis of the beta c chain demonstrates that only the membrane-proximal 62 amino acids of the cytosolic domain are required for JAK2 activation. Thus, JAK2 activation is correlated with induction of mitogenesis but does not, alone, activate the Ras pathway. Carboxyl truncations of the alpha chain, which inactivate the receptor for mitogenesis, are unable to mediate GM-CSF-induced JAK2 activation. Using baculovirus-expressed proteins, we further demonstrate that JAK2 physically associates with the beta c chain but not with the alpha chain. Together, the results further support the hypothesis that the JAK family of kinase are critical to coupling cytokine binding to tyrosine phosphorylation and ultimately mitogenesis.
Mol Cell Biol 1994 Jul
PMID:JAK2 associates with the beta c chain of the receptor for granulocyte-macrophage colony-stimulating factor, and its activation requires the membrane-proximal region. 800 42


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