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)

Transcriptional activation of human heat shock protein (HSP) genes by heat shock or other stresses is regulated by the activation of a heat shock factor (HSF). Activated HSF posttranslationally acquires DNA-binding ability. We previously reported that quercetin and some other flavonoids inhibited the induction of HSPs in HeLa and COLO 320DM cells, derived from a human colon cancer, at the level of mRNA accumulation. In this study, we examined the effects of quercetin on the induction of HSP70 promoter-regulated chloramphenicol acetyltransferase (CAT) activity and on the binding of HSF to the heat shock element (HSE) by a gel mobility shift assay with extracts of COLO 320DM cells. Quercetin inhibited heat-induced CAT activity in COS-7 and COLO 320DM cells which were transfected with plasmids bearing the CAT gene under the control of the promoter region of the human HSP70 gene. Treatment with quercetin inhibited the binding of HSF to the HSE in whole-cell extracts activated in vivo by heat shock and in cytoplasmic extracts activated in vitro by elevated temperature or by urea. The binding of HSF activated in vitro by Nonidet P-40 was not suppressed by the addition of quercetin. The formation of the HSF-HSE complex was not inhibited when quercetin was added only during the binding reaction of HSF to the HSE after in vitro heat activation. Quercetin thus interacts with HSF and inhibits the induction of HSPs after heat shock through inhibition of HSF activation.
Mol Cell Biol 1992 Aug
PMID:Inhibition of the activation of heat shock factor in vivo and in vitro by flavonoids. 132 38

A cDNA encoding a novel human glutamate receptor subunit protein was isolated from a human hippocampal library. This cDNA, termed humEAA2, is most closely related to rat cDNAs for kainate receptor proteins and, when expressed in COS cells, is associated with high affinity kainate receptor binding. The relative potency of compounds in displacing [3H]kainate binding was kainate greater than quisqualate greater than domoate greater than L-glutamate much greater than 6,7-dinitroquinoxaline-2,3-dione greater than dihydrokainate greater than 6-cyano-7-nitroquinoxaline-2,3-dione greater than (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid. Homomeric expression of humEAA2 does not appear to elicit ligand-gated channel activity. Nevertheless, the molecular structure and pharmacology of high affinity kainate binding suggest that humEAA2 is a novel subunit protein of a human kainate receptor complex.
Mol Pharmacol 1992 Jul
PMID:Molecular structure and pharmacological characterization of humEAA2, a novel human kainate receptor subunit. 132 49

Using a powerful expression cloning method in COS cells, we have cloned the TGF-beta types II and III receptors. The type III TGF-beta receptor is a membrane-bound proteoglycan with a core protein of about 110 kDa. Stable expression of the type III receptor in L6 myoblasts leads to an apparent increase in the ability of the type II receptor to bind iodinated TGF-beta 1. The cloned type II receptor has a predicted protein core of about 60 kDa with a cysteine-rich extracellular domain, a single transmembrane domain, and a functional serine/threonine kinase domain that is homologous to the activin receptor and to the C. elegans protein daf-1. These results implicate serine/threonine phosphorylation as an important mechanism of TGF-beta action.
Mol Reprod Dev 1992 Jun
PMID:Expression cloning of TGF-beta receptors. 132 47

Retinoic acid receptor (RAR) and thyroid hormone receptor (T3R) are structurally similar and can bind as homodimers or T3R-RAR heterodimers to a single synthetic DNA response element. The interaction of these two types of receptors with wild type elements, however, has not been systematically investigated. Promoter elements from genes regulated by retinoic acid (RA) or thyroid hormone (T3) were tested for response to T3 and RA in transient transfections in both JEG and COS cells. The elements were classified as primarily responsive to RA or to T3 or responsive to both ligands. Binding of highly purified RAR alpha and T3R alpha to the various elements was assessed using the gel shift assay. Those elements predominantly responsive to one ligand showed preferential binding to the appropriate receptor. A series of point mutations were introduced into the rat GH T3 response element to further define sequence requirements for response to both RA and T3. Down-mutations in any of the three hexamers (previously demonstrated to be required for full response to T3 and full binding of T3R) also decreased RA induction and RAR binding. However, only one of two sets of up-mutations for T3 response also increased RA induction, demonstrating differences in hexamer preference between RAR and T3R. Variation in spacing of the three hexamers did not influence RA vs. T3 induction or RAR vs. T3R binding according to the predictions of a simple hexamer spacing model. There was a strong correlation between the extent of T3R dimer binding and strength of T3 induction for a subset of elements studied in JEG cells (r = 0.97, P < 0.01) and a weaker but significant correlation in COS cells (r = 0.65, P < 0.05)). In contrast, RAR dimer binding by the wild type elements did not quantitatively correlate with RA induction in either JEG (r = 0.13, P > 0.05) or COS cells (r = 0.21, P > 0.05). These results suggests that RAR interacts with a heterodimer partner(s) which influences binding site specificity, whereas T3R heterodimer partner(s) is less likely to alter binding site recognition. The observed difference in COS and JEG cells as well as the weak T3R binding-function relationship of the malic enzyme element, however, suggest that the influence of T3R heterodimer partner(s) on binding site specificity is likely to vary with cell type and the specific element tested.
Mol Endocrinol 1992 Oct
PMID:Differential capacity of wild type promoter elements for binding and trans-activation by retinoic acid and thyroid hormone receptors. 133 48

We previously reported the cloning of two distinct somatostatin receptor (SSTR) subtypes, SSTR1 and SSTR2. Although both SSTR1 and SSTR2 bound somatostatin specifically and with high affinity, neither was coupled to adenylyl cyclase, a major cellular effector of somatostatin's actions. Here we report the cloning and functional characterization of a third member of the SSTR family. Human SSTR3 is a protein of 418 amino acids and has 45% and 46% identity with human SSTR1 and SSTR2, respectively. RNA blotting studies showed that SSTR3 mRNA could be readily detected in brain and pancreatic islets. The pharmacological properties of human SSTR3 were characterized by transiently expressing the human SSTR3 gene in COS-1 cells. Membranes from cells expressing human SSTR3 bound the somatostatin agonist [125I]CGP 23996 specifically and with high affinity, with a rank order of potency of somatostatin-28 = CGP 23996 > somatostatin-14 > SMS-201-995. Studies using cells transiently coexpressing the human dopamine D1 receptor and human SSTR3 showed that somatostatin was able to inhibit dopamine-stimulated cAMP formation in a dose-dependent manner, indicating that SSTR3 was functionally coupled to adenylyl cyclase. These results indicate that the diverse biological effects of somatostatin are mediated by a family of receptor with distinct, but overlapping, tissue distributions, unique pharmacological properties, and potentially different functions.
Mol Endocrinol 1992 Dec
PMID:Somatostatin receptors, an expanding gene family: cloning and functional characterization of human SSTR3, a protein coupled to adenylyl cyclase. 133 45

Complementary DNA (cDNA) clones containing the entire coding region of human choline acetyltransferase (ChAT) were isolated from cDNA libraries prepared from the autopsied spinal cord. In the human cDNA, the ATG codon assigned to the putative initiation codon for pig, rat and mouse ChAT cDNAs was replaced by ACG. The human cDNA contained an in-frame ATG codon 324 nucleotides upstream of the ACG codon. Therefore, human ChAT cDNA should code for a 748 amino acid polypeptide of 82.6 kDa. This deduced molecular weight was larger than that of ChAT protein purified from the human brain and placenta (64-70 kDa). The human ChAT cDNA containing the entire coding region was ligated to an expression vector and introduced into African green monkey kidney (COS) cells and Chinese hamster ovary (CHO) cells. The cells expressed high ChAT activity and produced two protein bands immunostained with an antibody to monkey ChAT. The molecular weight of the proteins was estimated to be approximately 70 and 80 kDa by polyacrylamide-SDS gel electrophoresis. When partial cDNAs that lacked the first ATG but contained the replaced ACG codon were introduced into COS cells, the cells expressed moderate ChAT activity and an immunoreactive protein band of 70 kDa. These results indicate that translation of human ChAT mRNA starts at two sites and produces two enzyme proteins with different molecular weights. It might be that the larger form of ChAT molecule is an enzyme precursor for processing or that the N-terminal extrapeptide is needed for subcellular localization of the enzyme.
Brain Res Mol Brain Res 1992 Dec
PMID:A complementary DNA for human choline acetyltransferase induces two forms of enzyme with different molecular weights in cultured cells. 133 37

We have isolated a bovine prolactin (bPRL) receptor cDNA from an endometrial cDNA library, which predicts a 557 amino acid transmembrane protein similar to the long forms of other characterized prolactin receptors. The predicted cytoplasmic domain is slightly truncated primarily by a stop codon located 36 codons 5' from the stop utilized in the human hepatic transcript. When expressed in COS cells, this cDNA was shown to encode a protein which bound bovine placental lactogen (bPL) and bPRL with nearly equal affinity (KD for bPL, 2.03 x 10(-10) M; bPRL, 3.07 x 10(-10) M). Northern analysis demonstrated multiple transcripts, with maternal liver, corpus luteum, intestine, endometrium and fetal liver containing a major transcript of about 3.8 kb, and maternal corpus luteum and endometrium, a second sized transcript of apparently equal abundance of 4.4 kb. This difference did not appear to be within the coding region. Primer extension analysis of maternal hepatic and endometrial transcripts revealed considerable heterogeneity. Examination of the distribution of prolactin and growth hormone receptor transcripts at mid-pregnancy by semi-quantitative reverse transcriptase polymerase chain reaction showed that both are widespread in bovine fetal and placental tissues. This isolation of bovine prolactin receptor cDNA, and description of receptor distribution will facilitate study of the action of the placental and pituitary members of this gene family during pregnancy.
Mol Cell Endocrinol 1992 Nov
PMID:Molecular cloning of the bovine prolactin receptor and distribution of prolactin and growth hormone receptor transcripts in fetal and utero-placental tissues. 133 25

We have isolated the gonadotropin-releasing hormone receptor (GnRH-R) from a rat anterior pituitary cDNA library, determined its sequence and demonstrated receptor function. The 2.2 kb rat GnRH-R clone encodes a protein of 327 amino acids. A 1.3 kb clone encoding the mouse GnRH-R has previously been described (Tsutsumi et al., 1992). Although both the mouse and rat protein share significant homology with molecules belonging to the family of G protein-coupled receptors, they have certain unusual features, an example being the complete absence of a COOH terminal tail. The 3'-untranslated region reported missing in the mouse is present in the rat cDNA, where an extended 1 kb of 3'-untranslated region extending to the poly-A tail is shown. At the amino acid level, the rat GnRH-R shows considerable homology with that of the mouse. Electrophysiological studies with Xenopus oocytes and transfection of the cDNA into COS-1 cells, have shown that the 2.2 kb cDNA clone encodes a functional receptor.
Mol Cell Endocrinol 1992 Dec
PMID:Molecular cloning and characterisation of the rat pituitary gonadotropin-releasing hormone (GnRH) receptor. 133 27

On the basis of extensive radioligand data and more limited functional data, three pharmacological subtypes of alpha 2-adrenergic receptors have been identified. More recently, three human genes or cDNAs for alpha 2-adrenergic receptors have been identified by molecular cloning. The relationship, however, among the pharmacologically defined subtypes and those identified by molecular cloning has not been clear. In order to resolve this issue, we have compared the pharmacological characteristics of the receptors identified by molecular cloning and expressed in COS-7 cells with the characteristics of the pharmacologically defined receptors in their respective prototypic tissue or cell line. The affinities (Ki values) of 12 subtype-selective alpha 2-adrenergic antagonists were determined for the alpha 2 receptor in the six preparations, by radioligand binding. Correlation analyses of the pKi values indicate that the alpha 2A subtype, as defined in the HT29 cell line, the alpha 2B receptor of the neonatal rat lung, and the alpha 2C subtype, as defined in an oppossum kidney cell line, correspond to the cloned human alpha 2-C10, alpha 2-C2, and alpha 2-C4 receptor subtypes, respectively.
Mol Pharmacol 1992 Jul
PMID:Pharmacological characteristics of alpha 2-adrenergic receptors: comparison of pharmacologically defined subtypes with subtypes identified by molecular cloning. 135 47

Molecular cloning and ligand binding studies have shown the alpha 2 class of adrenergic receptor (alpha 2-AR) to be a family of at least three related subtypes in humans. These studies have not, however, identified distinct subtype-specific functions for these receptors in vivo. It should be possible to extend the analysis of alpha 2-AR subtype function to the animal level through the use of experimental mammalian embryology in mice. To begin this process, we have isolated two mouse genomic clones encoding alpha 2-AR subtypes and expressed these genes in COS-7 cells for binding studies. Sequence homology and ligand binding data allow the assignment of one clone (M alpha 2-4H) as the mouse homolog of the human alpha 2-C4 subtype. The other clone (M alpha 2-10H) closely resembles the human alpha 2-C10 subtype in sequence but binds with significantly lower affinity to yohimbine and rauwolscine, members of a distinct class of bulky alpha 2-selective antagonists commonly used to evaluate alpha 2-AR function in vivo. To define the domain(s) responsible for this unusual binding property, we constructed a series of M alpha 2-10H/human alpha 2-C10 chimeric receptors. Analysis of these receptors identified a conservative Cys201 to Ser201 change in the fifth transmembrane domain of M alpha 2-10H as being responsible for the low affinity of the mouse receptor for yohimbine.
Mol Pharmacol 1992 Jul
PMID:Cloning of two mouse genes encoding alpha 2-adrenergic receptor subtypes and identification of a single amino acid in the mouse alpha 2-C10 homolog responsible for an interspecies variation in antagonist binding. 135 49


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