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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this report, we show that the overexpression of tissue transglutaminase (tTG) in the human neuroblastoma cell line SK-N-BE(2) renders these neural crest-derived cells highly susceptible to death by apoptosis. Cells transfected with a full-length tTG cDNA, under the control of a constitutive promoter, show a drastic reduction in proliferative capacity paralleled by a large increase in cell death rate. The dying tTG-transfected cells exhibit both cytoplasmic and nuclear changes characteristic of cells undergoing apoptosis. The tTG-transfected cells express high Bcl-2 protein levels as well as phenotypic neural cell adhesion molecule markers (NCAM and neurofilaments) of cells differentiating along the neuronal pathway. In keeping with these findings, transfection of neuroblastoma cells with an expression vector containing segments of the human tTG cDNA in antisense orientation resulted in a pronounced decrease of both spontaneous and retinoic acid (RA)-induced apoptosis. We also present evidence that (i) the apoptotic program of these neuroectodermal cells is strictly regulated by RA and (ii) cell death by apoptosis in the human neuroblastoma SK-N-BE(2) cells preferentially occurs in the substrate-adherent phenotype. For the first time, we report here a direct effect of tTG in the phenotypic maturation toward apoptosis. These results indicate that the tTG-dependent irreversible cross-linking of intracellular protein represents an important biochemical event in the induction of the structural changes featuring cells dying by apoptosis.
Mol Cell Biol 1994 Oct
PMID:Tissue transglutaminase and apoptosis: sense and antisense transfection studies with human neuroblastoma cells. 793 79

Transglutaminase, a zero length cross-linker that catalyzes the formation of isopeptide bonds between proximal Gln and Lys side chains, was used as a structural and conformational probe of the hexadecameric phosphorylase kinase molecule (alpha beta gamma delta)4. Brief cross-linking of nonactivated kinase caused formation of alpha-beta dimers, with no cross-linking involving the gamma- and delta-subunits. When the kinase was first activated by autophosphorylation, significant amounts of alpha-alpha dimers were also observed in addition to the alpha-beta, demonstrating the occurrence of a conformational change in the alpha-subunits concomitant with activation. Both dimers resulted from intramolecular cross-linking. Because the COOH-terminal regions of the alpha-subunits are at the lobe tips of this bilobal kinase (Wilkinson D. A. Marion, T. N., Tillman, D. M., Norcum, M. T., Hainfeld, J. F., Seyer, J. M., and Carlson, G. M. (1994) J. Mol. Biol. 235, 974-982), the formation of zero length cross-linked alpha-alpha dimers indicates that the polypeptide backbones of these subunits must stretch from the lobe tips to a more central location where they abut each other. Excess putrescine, as the amine substrate in place of endogenous Lys, was incorporated by transglutaminase predominately into the alpha-subunits of the kinase, with only slight modification of the beta- and gamma-subunits. Exogenous calmodulin (delta'), an activator of the kinase with a binding site on the alpha-subunits (James, P., Cohen, P., and Carafoli, E. (1991) J. Biol. Chem. 266, 7087-7091), was a potent inhibitor of cross-linking. It also inhibited incorporation of putrescine into the alpha-subunits but stimulated incorporation into the beta- and gamma-subunits. Heparin, another activator of the kinase, had the same effects as exogenous calmodulin on cross-linking and putrescine incorporation, suggesting a commonality in the mechanism through which these two effectors activate the holoenzyme, including promoting a conformational change that increases the surface accessibility of target Gln residues on the catalytic gamma-subunit.
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PMID:Zero length conformation-dependent cross-linking of phosphorylase kinase subunits by transglutaminase. 796 56

The present study examines interferon-gamma (IFN gamma)-induced changes in the expression of immunomodulatory genes, proliferation-associated genes, and squamous-specific genes in primary cultures of human bronchial epithelial cells and fibroblasts. IFN gamma induced the expression of guanylate binding protein (GBP or p67) and the MHC class II antigen, HLADR alpha, in both epithelial cells and fibroblasts. In contrast, the expression of complement component C3 was induced in bronchial epithelial cells but not in fibroblasts. Similarly, IFN gamma induced growth arrest (EC50 approximately 50 U/ml) only in bronchial epithelial cells. This growth arrest was accompanied by a down-regulation of cdc2, E2F-1, and p53 mRNA levels and was associated with expression of the squamous-specific marker genes, transglutaminase type I and cornifin. These findings are consistent with IFN gamma inducing squamous differentiation in bronchial epithelial cells. In contrast, several lung carcinoma cell lines did not respond to IFN gamma with respect to the down-regulation of proliferation-associated genes or the induction of squamous-specific genes. However, GBP expression was induced in all the cell lines in response to IFN gamma. The present study demonstrates that cultured human bronchial epithelial cells are sensitive to the immunomodulatory, growth-inhibitory, and differentiation-inducing properties of IFN gamma. In contrast, several lung carcinoma cell lines are insensitive to the growth-inhibitory and differentiation-inducing actions of IFN gamma, suggesting they may have acquired defects in certain IFN gamma signaling pathways. Although the growth of human bronchial fibroblasts is not altered, expression of certain immunomodulatory genes is induced by IFN gamma.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Respir Cell Mol Biol 1994 Aug
PMID:Differential responsiveness of human bronchial epithelial cells, lung carcinoma cells, and bronchial fibroblasts to interferon-gamma in vitro. 804 75

In the present study we describe the full length cDNA sequence for rabbit transglutaminase type I as well as the sequence for a 2.9-kilobase (kb) promoter fragment of the gene. Transglutaminase type I mRNA expression was inhibited in squamous differentiating epithelia by retinoic acid (RA) in a dose-dependent (EC50 = 1-2 nM) and transcriptional manner. In human epidermal keratinocytes transglutaminase type I mRNA was induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment, and this induction could be inhibited by bryostatin 1. In contrast, TPA treatment inhibited the expression of c-myc mRNA. Bryostatin 1 but not RA could prevent this decrease in c-myc mRNA expression, indicating that transglutaminase type I mRNA expression was associated with differentiation and not growth arrest. An SP1 element was found within 50 base pairs 5' of the transcription initiation site. A TATA-like element (CATAAAC) was found but was not capable of activating transcription. In addition, putative response elements for C-MYC, Ker1/AP2, 2 AP1 sites, a CK-8-mer, and an AP2 site were present in the 2.9-kb fragment. Transfection of RbTE cells with the 2.9-kb fragment ligated to a promoterless luciferase vector resulted in 2.2-fold more luciferase expression in differentiated vs. undifferentiated cells. Furthermore, luciferase activity was induced 7.4-fold in human epidermal keratinocytes induced to differentiate with TPA. TPA-induced luciferase activity was inhibited by both bryostatin 1 and RA. No known RA response elements were identified in the promoter.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Endocrinol 1993 Mar
PMID:Regulation of transglutaminase type I expression in squamous differentiating rabbit tracheal epithelial cells and human epidermal keratinocytes: effects of retinoic acid and phorbol esters. 809 65

Rapid changes in transglutaminase (TG) activity, 45Ca(2+)-influx and [3H]leucine incorporation in superior cervical ganglia (SCG), and nodose ganglia (NG) excised from adult rats were examined following addition of membrane-depolarizing agents veratridine (Ver) or high extracellular [K+]o during aerobic incubation in vitro at 37 degrees C. Addition of KCl (50 mM) stimulated TG activity to a maximal extent (four to six-fold) in SCG and NG after 30 min. Ver (0.2 mM) also increased TG activity in both ganglia after 30 min. Kinetic studies showed that the stimulation of TG activity in both ganglia caused by each depolarization condition was associated with a decrease in Km and an increase in Vmax value. The depolarizing agents Ver and high [K+]o also caused significant increases in 45Ca2+ influx into both ganglia. The Ver-induced increases in TG activity and 45Ca2+ accumulation were antagonized by tetrodotoxin (TTX, 1 microM), a sodium channel blocker. The K(+)-induced increase in TG activity was not blocked by tetraethylammonium (TEA, 20 mM), a potassium channel antagonist, although TEA did block the K(+)-induced increase in 45Ca2+ accumulation. The membrane-perturbing, sialic acid-containing compounds, GM1-ganglioside (GM1, 5 nM) and alpha-sialyl cholesterol (alpha-SC, 20 microM), were moderate inhibitors of the K(+)-induced effects on TG activity and 45Ca2+ accumulation. The sialyl compounds had little effect on Ver-induced accumulation of 45Ca2+ but enhanced the Ver-evoked stimulation in TG activity. These results suggests that the veratridine- and K(+)-induced increases in TG activity occur via modulation of Ca2+ and Na+ channel gating mechanisms that are pharmacologically distinct for each depolarizing agent. The veratridine- and K(+)-induced decrease in [3H]leucine incorporation could be a result of stimulation of TG activity as a consequence of degenerative alterations.
Mol Chem Neuropathol
PMID:Effects of depolarizing agents on transglutaminase activity, Ca2+ influx, and protein synthesis in superior cervical and nodose ganglia excised from rats. 810 33

Yoshida tumor cells contain consistent amounts of type 2 transglutaminase, along with a membrane bound form of the enzyme. Digitonin permeabilized cells retain a large proportion of type 2 TGase and of substrate proteins which are labelled by radioactive putrescine in the presence of calcium. GTP inhibits protein labelling at low calcium concentration by inhibiting type 2 TGase without affecting membrane-bound TGase. These results support the notion that inhibition of type 2 TGase by GTP is physiologically relevant.
Biochem Mol Biol Int 1993 Jul
PMID:Regulation of transglutaminase activity by GTP in digitonin permeabilized Yoshida tumor cells. 810 19

We have used antisense RNA technology to inhibit endogenous PTH-related peptide (PTHRP) production in an established human keratinocyte cell line, HPK1A, to assess the role of PTHRP as a modulator of cell differentiation. Initially to determine the specificity of any alterations in cell function that might be observed, HPK1A cells and Rat-2 fibroblasts (which do not synthesize PTHRP) were both infected with the same retrovirus (pYN) containing antisense PTHRP. In contrast to antisense-infected HPK1A cells (HPK1A-AS), which show accelerated growth indices when endogenous PTHRP production is blocked, antisense-infected Rat-2 cells (Rat-2-AS) displayed no increase in cell proliferation. Consequently, this alteration in HPK1A cell function appeared to be specific to the inhibition of PTHRP production. In HPK1A-AS cells, no PTHRP transcript was observed in cytoplasmic RNA, and none was sequestered in a nuclear RNA preparation. Therefore, hybridization with the antisense strand appears to destabilize PTHRP mRNA, leading to rapid disappearance of the sense-antisense heteroduplex. We then examined the effect of PTHRP inhibition on keratinocyte differentiation using three indices. PTHRP inhibition in HPK1A-AS cells resulted in reduced high mol wt keratin production, as assessed by immunocytochemistry. Expression of mRNA encoding transglutaminase and involucrin was decreased in HPK1A-AS cells compared to that in control cells under conditions of high ambient calcium. Involucrin protein levels were also diminished in HPK1A-AS cells in parallel with the reduced levels of involucrin gene expression. These data, therefore, show that interference with PTHRP production inhibits expression of maturation-specific keratinocyte indices and indicate that endogenous PTHRP acts to enhance differentiation in this keratinocyte model.
Mol Endocrinol 1994 Feb
PMID:Antisense-mediated inhibition of parathyroid hormone-related peptide production in a keratinocyte cell line impedes differentiation. 817 Apr 70

After weaning, the mammary gland ceases lactation and involutes. The wet weight of the gland decreases by 70% within 4 days of weaning. This involves significant tissue remodelling as the ducts regress and return to the resting state. The presence of apoptotic bodies in the luminal epithelial compartment 2 to 3 days after weaning provides clear evidence that a substantial proportion of the regression is attributable to the induction of active cell death (ACD) of the epithelial cells. These changes in the architecture of the gland were found to be mirrored by changes in gene expression. The steady-state level of beta-casein mRNA decreased rapidly after weaning from the high levels seen during lactation to undetectable levels by 8 days after weaning. The steady-state levels of expression of a number of genes associated with ACD, including TRPM-2, tissue transglutaminase (TGase) and poly(ADP-ribose) polymerase (PARP), increased transiently during this time-frame. The steady-state level of TRPM-2 mRNA increased 2 days after weaning, reaching a peak on day 4, and decreasing to undetectable levels by day 8 after weaning. The steady-state levels of two other mRNAs, TGase and PARP, showed very similar kinetics. In contrast, the mRNA for Hsp 27, which has been shown to be induced during prostate regression, was not significantly induced in the regressing mammary gland. In-situ hybridization demonstrated that the TRPM-2, TGase and PARP genes were expressed predominantly in the luminal epithelial cells of the ducts. These cells expressed beta-casein mRNA during lactation, and underwent ACD after weaning. While the ultrastructural changes in the mammary gland after weaning, and the induction of TRPM-2, TGase and PARP mRNAs, are reminiscent of apoptosis in the prostate, several features of the process are different. Most notably, the disruption of the secretory processes and the lack of increased expression of Hsp 27 in the regressing mammary gland suggest that there may be a number of important events in ACD that are not common to all cells.
J Mol Endocrinol 1994 Feb
PMID:Induction of gene expression during involution of the lactating mammary gland of the rat. 818 14

Human plasma fibronectin is a high molecular weight (530,000), multi-domain, modular glycoprotein, consisting of two nearly identical subunits disulfide-bridged close to their C-terminal ends. Three sites that can be differentially labeled with fluorescent probes are present on each fibronectin subunit, the transglutaminase-sensitive Gln3 residue and the two free sulfhydryl residues, Cys1201 and Cys2196. These sites are located, respectively, in the N-terminal heparin/fibrin-binding domain, between the central DNA and cell-binding domains, and just before the C-terminal fibrin-binding domain. To map the relative spatial arrangement of these domains, steady-state and lifetime fluorescence energy transfer techniques were employed. Our results show that the minimal intramolecular distances between the labeled Gln3-Cys1201 and Gln3-Cys2196 pairs are 5.5(+/- 0.6) nm and 5.7(+/- 0.7) nm, respectively, as measured by steady-state methods. Lifetime methods gave somewhat higher distances of 8.1(+/- 0.2) nm and 7.6(+/- 0.2) nm, respectively, between these sites. The binding of heparin or subjection to high ionic strength had only a minor effect, while in the presence of 50% (w/v) glycerol, an increase of about 25% in the intramolecular distances between these sites was observed. A similar effect was induced by binding of fibronectin to the surface of Cytodex beads, an event which was previously shown instead to markedly increase the intersubunit distances between the Gln3-Gln3 and Cys1201-Cys1201 pairs. The solution structure of fibronectin was further investigated by elastic light-scattering and circular dichroism measurements. By elastic light-scattering, the radius of gyration of fibronectin was found to be 15.3(+/- 0.8) nm in the presence of 30% (w/v) glycerol, in contrast to a value of 8.6(+/- 0.3) nm under physiological conditions. Far and near ultraviolet circular dichroism spectra showed that only minor changes in the secondary structure of fibronectin take place on increasing the glycerol content of the solvent up to 34% (w/v). Our results complement previously available information on the solution structure of fibronectin and on its transition from the native compact conformation to a more expanded form on increasing ionic strength or glycerol content. In either situation, fibronectin seems to retain a basic structural core, in which the N-terminal, the central and the C-terminal regions of the two subunits strongly interact with each other. A major role of hydrophobic forces, in stabilizing the fibronectin conformations under these conditions, is therefore postulated. The transition to the extended forms seen in many electron micrographs can instead be explained by disruption of the proposed structural core upon adsorption to surfaces.
J Mol Biol 1993 Mar 20
PMID:Solution structure of human plasma fibronectin under different solvent conditions. Fluorescence energy transfer, circular dichroism and light-scattering studies. 846 68

alpha 1-Adrenoceptors in most tissues couple with the heterotrimeric GTP-binding protein Gq, the alpha subunit of which activates the beta-isoforms of phospholipase C. However, in heart (and in liver) alpha 1-adrenoceptors have been reported to couple to a high molecular weight GTP-binding protein. Gh, which functions both as a type II transglutaminase and as a receptor coupling protein. Gh activates a phospholipase isoform distinct from phospholipase C-beta. Here we report that isolation and culture of neonatal cardiomyocytes decreased the expression of Gh without reducing the content of Gq or Gi. Gh was readily detected in extracts from intact neonatal and adult heart tissues. The expression of Gh thus appears to be a feature of intact cardiac tissue.
J Mol Cell Cardiol 1995 Oct
PMID:Isolation of neonatal cardiomyocytes reduces the expression of the GTP-binding protein, Gh. 857 53


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