Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:B0FTZ7 (catenin)
 18,795 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alterations in intercellular junction and membrane cytoskeletal proteins may underlie some of the morphological, invasive and metastatic properties of cancer. E-cadherin, a transmembrane protein that functions in epithelial cell-cell interactions at adherens junctions, is linked to the membrane cytoskeletal matrix through interactions with alpha- and beta-catenin. We have carried out studies of E-cadherin and alpha- and beta-catenin in 18 breast cancer cell lines to determine the prevalence and nature of alterations in these genes in breast cancer. Ten lines failed to express E-cadherin protein at detectable levels and seven failed to produce detectable levels of E-cadherin transcripts. In a line lacking E-cadherin expression (SK-BR-3) a homozygous deletion of a large portion of the E-cadherin gene was noted. Localized sequence alterations in E-cadherin transcripts were not identified in any lines. In contrast to the results of a previous study, no relationship was identified between E-cadherin expression and HER-2/NEU expression. Two of the 18 lines had no detectable alpha-catenin protein and six others had reduced levels. The two lines lacking alpha-catenin protein had reduced or undetectable levels of alpha-catenin transcripts, while no consistent changes in alpha-catenin transcript levels were seen in the lines with reduced, but detectable, levels of alpha-catenin protein. Similarly, although two lines lacked beta-catenin protein, in most lines the levels of beta-catenin transcripts and protein were not well correlated with one another. Our findings suggest that alterations in E-cadherin and alpha- and beta-catenin expression are frequent in human breast cancer-derived cell lines, and that in some cases the decreased expression may result from mutations in the genes. Furthermore, the frequent alterations in the expression of these proteins argue that loss of function in the E-cadherin-catenin pathway may be critical in the development of many breast cancers.
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PMID:Frequent alterations in E-cadherin and alpha- and beta-catenin expression in human breast cancer cell lines. 747 52

The calcium-dependent class of cell adhesion molecules known as cadherins mediate homotypic cell interactions in most epithelia. We have now investigated the expression and distribution of cadherins and cadherin-associated molecules in the developing and maturing rat testis. E-Cadherin was not detected in the seminiferous tubule at any time in development or in the adult. In contrast, Leydig cells expressed E-cadherin between day 15 of gestation and postnatal day 3. alpha- and beta-catenins were expressed throughout the developing testis, but were particularly prominent in Leydig cells. In the maturing testis, alpha-catenin and plakoglobin became progressively more restricted to the basal part of the seminiferous epithelium and by 23 days exhibited a pattern characteristic of the Sertoli cell junctional complex. beta-Catenin recruitment to the Sertoli cell junctional complex was not complete until 60 days. alpha-Catenin and plakoglobin were not present at sites of Sertoli cell-germ cell contacts. Northern blot analysis of testicular RNA showed three mRNA species hybridizing with N-cadherin cDNA. A pan-cadherin antibody specific for a region of the highly conserved C-terminal of all cadherins stained sites of Sertoli-spermatocyte and Sertoli-round spermatid contact in the adult rat seminiferous epithelium, but did not stain the Sertoli cell tight junctional complex. Western blots of testicular extracts indicated that the molecule(s) recognized by these antibodies had an approximate molecular mass of 120 kilodalton, typical of members of the cadherin family. Therefore, although Sertoli cells do not express E-cadherin, another member(s) of the cadherin family is present in the testis, but may not be directly involved in tight junction dynamics as in other cells. Instead, cadherin-mediated adhesion is likely to be involved in Sertoli cell-germ cell interactions. As catenins are not present at these sites, our results suggest a catenin-independent role of cadherins in germ cell adhesion to Sertoli cells.
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PMID:Cadherins and cadherin-associated molecules in the developing and maturing rat testis. 750 30

The cadherin-catenin complex has an important role in cell-cell adhesion and may also function in signaling pathways. We report that overexpression of three cadherin types in Xenopus embryos causes them to develop with reduced dorsal axial structures. The same phenotype is produced in embryos that have been depleted of maternal beta-catenin protein by an antisense oligodeoxynucleotide complementary to beta-catenin mRNA. They show an inhibition in the expression of dorsal mesodermal markers MyoD and goosecoid, but not of ventral and general mesodermal markers. They lack notochords, somites, and neural tubes and are defective in dorsal mesodermal signaling in Nieuwkoop assays. The phenotype can be rescued by the injection of beta-catenin mRNA and not by the injection of Xwnt-8 mRNA. These results show that beta-catenin has an important role in dorsal mesoderm induction. They directly demonstrate the activity of a maternal mRNA in axis specification.
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PMID:Overexpression of cadherins and underexpression of beta-catenin inhibit dorsal mesoderm induction in early Xenopus embryos. 752 1

Loss of epithelioid organization in carcinoma cell lines has been related to invasiveness and poor differentiation of tumors. We investigated the invasion in vitro of various human colon cancer cell lines. Most cell lines were noninvasive into chick heart fragments, and this correlated with an epithelioid morphotype. Only cell lines COLO320DM, SW620, and variants of HCT-8 and DLD-1 were invasive and nonepithelioid. We examined in these cell lines whether invasiveness was related to changes in the structure and function of the E-cadherin/catenin complex. E-cadherin functions as an invasion suppressor and as a cell-cell adhesion molecule when linked to the cytoskeleton via alpha-catenin plus beta- or gamma-catenin. All noninvasive cell lines showed E-cadherin linked to these catenins. The E-cadherin-dependent cell-cell adhesion function in these cell lines was demonstrated by two assays in vitro. It was interesting that all invasive cell lines showed a dysfunctional E-cadherin/catenin complex. COLO320DM, SW480, and SW620 cells were defective in E-cadherin expression, whereas the invasive variants of HCT-8 and DLD-1 lacked the alpha-catenin protein. From clonal epithelioid HCT-8 cultures with functional E-cadherin/catenin complexes, we subcloned, repeatedly, round cell variants that were again invasive and expressed no alpha-catenin protein. Our data suggest that reproducible transformations toward a more invasive phenotype in HCT-8 cells are associated with down-regulation of alpha-catenin. The mechanisms of this transformation and the level of alpha-catenin down-regulation are currently investigated.
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PMID:Transition from the noninvasive to the invasive phenotype and loss of alpha-catenin in human colon cancer cells. 755 55

Calcium-dependent homotypic cell-cell adhesion, mediated by molecules such as E-cadherin, guides the establishment of classical epithelial cell polarity and contributes to the control of migration, growth, and differentiation. These actions involve additional proteins, including alpha- and beta-catenin (or plakoglobin) and p120, as well as linkage to the cortical actin cytoskeleton. The molecular basis for these interactions and their hierarchy of interaction remain controversial. We demonstrate a direct interaction between F-actin and alpha (E)-catenin, an activity not shared by either the cytoplasmic domain of E-cadherin or beta-catenin. Sedimentation assays and direct visualization by transmission electron microscopy reveal that alpha 1(E)-catenin binds and bundles F-actin in vitro with micromolar affinity at a catenin/G-actin monomer ratio of approximately 1:7 (mol/mol). Recombinant human beta-catenin can simultaneously bind to the alpha-catenin/actin complex but does not bind actin directly. Recombinant fragments encompassing the amino-terminal 228 residues of alpha 1(E)-catenin or the carboxyl-terminal 447 residues individually bind actin in cosedimentation assays with reduced affinity compared with the full-length protein, and neither fragment bundles actin. Except for similarities to vinculin, neither region contains sequences homologous to established actin-binding proteins. Collectively these data indicate that alpha 1 (E)-catenin is a novel actin-binding and -bundling protein and support a model in which alpha 1(E)-catenin is responsible for organizing and tethering actin filaments at the zones of E-cadherin-mediated cell-cell contact.
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PMID:Alpha 1(E)-catenin is an actin-binding and -bundling protein mediating the attachment of F-actin to the membrane adhesion complex. 756 23

A pseudogene (CTNNAP1) for the human alpha E-catenin gene was isolated from a human genomic phage library. The pseudogene sequence shows 90% similarity to the alpha E-catenin mRNA at the nucleotide level. Thirty-eight stop codons in all three reading frames and multiple other mutations were found, indicating that the pseudogene does not encode a functional protein. No introns were found in the region corresponding to the open reading frame of the alpha E-catenin cDNA, and two direct repeats flank this same region. Hence, the pseudogene can be classified as a processed pseudogene. Polymerase chain reaction with pseudogene-specific primers on genomic DNA and cDNA from human cell lines and healthy blood donors demonstrated the general occurrence of the pseudogene and the lack of its transcription. By fluorescence in situ hybridization the pseudogene was mapped to human chromosome 5q22 and the alpha E-catenin gene to the formerly disputed locus 5q31. This is the first report of a pseudogene for a member of the cadherin-catenin cell-cell adhesion complex.
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PMID:Isolation and characterization of a human pseudogene (CTNNAP1) for alpha E-catenin (CTNNA1): assignment of the pseudogene to 5q22 and the alpha E-catenin gene to 5q31. 760 73

Cadherins and catenins play an important role in cell-cell adhesion. Two of the catenins, beta and gamma, are members of a group of proteins that contains a repeating amino acid motif originally described for the Drosophila segment polarity gene armadillo. Another member of this group is a 120-kD protein termed p120, originally identified as a substrate of the tyrosine kinase pp60src. In this paper, we show that endothelial and epithelial cells express p120 and p100, a 100-kD, p120-related protein. Peptide sequencing of p100 establishes it as highly related to p120. p120 and p100 both appear associated with the cadherin/catenin complex, but independent p120/catenin and p100/catenin complexes can be isolated. This association is shown by coimmunoprecipitation of cadherins and catenins with an anti-p120/p100 antibody, and of p120/p100 with cadherin or catenin antibodies. Immunocytochemical analysis with a p120-specific antibody reveals junctional colocalization of p120 and beta-catenin in epithelial cells. Catenins and p120/p100 also colocalize in endothelial and epithelial cells in culture and in tissue sections. The cellular content of p120/p100 and beta-catenin is similar in MDCK cells, but only approximately 20% of the p120/p100 pool associates with the cadherin/catenin complex. Our data provide further evidence for interactions among the different arm proteins and suggest that p120/p100 may participate in regulating the function of cadherins and, thereby, other processes influenced by cell-cell adhesion.
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PMID:p120, a p120-related protein (p100), and the cadherin/catenin complex. 761 37

A number of genetic changes have been documented in prostate cancer, ranging from allelic loss to point mutations and changes in DNA methylation patterns (summarized in Fig. 1). The most consistent changes seen are those of allelic loss events, with the majority of tumours examined showing loss of alleles from at least one chromosomal arm. The short arm of chromosome 8, followed by the long arm of chromosome 16, seem to be the most frequent regions of loss, suggesting the presence of novel tumour suppressor genes. Deletions of one copy of the RB and TP53 genes are less frequent as are mutations of the TP53 gene, and accumulating evidence suggests the presence of an additional tumour suppressor gene on chromosome 17p, which is frequently inactivated in prostate cancer. Alterations in the E-cadherin/alpha catenin mediated cell-cell adhesion mechanism appear to be present in almost half of all prostate cancers and may be critical to the acquisition of metastatic potential of aggressive prostate cancers. Finally, altered DNA methylation patterns have been found in the majority of prostate cancers examined, suggesting widespread alterations in methylation modulated gene expression. The presence of multiple changes in these tumours is consistent with the multistep nature of the transformation process. Finally, efforts to identify prostate cancer susceptibility loci are under way, which may elucidate critical early events in prostatic carcinogenesis.
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PMID:Molecular biology of prostate cancer progression. 762 57

The FER gene encodes a cytoplasmic tyrosine kinase with a single SH2 domain and an extensive amino terminus. In order to understand the cellular function of the FER kinase, we analyzed the effect of growth factor stimulation on the phosphorylation and activity of FER. Stimulation of A431 cells and 3T3 fibroblasts with epidermal growth factor or platelet-derived growth factor results in the phosphorylation of FER and two associated polypeptides. The associated polypeptides were shown to be the epidermal growth factor receptor or the platelet-derived growth factor receptor and a previously identified target, pp120. Since pp120 had previously been shown to interact with components of the cadherin-catenin complex, these results implicate FER in the regulation of cell-cell interactions. The physical association of FER with pp120 was found to be constitutive and was mediated by a 400-amino-acid sequence in the amino terminus of FER. Analyses of that sequence revealed that it has the ability to form coiled coils and that it oligomerizes in vitro. The identification of a coiled coil sequence in the FER kinase and the demonstration that the sequence mediates association with a potential substrate suggest a novel mechanism for signal transduction by cytoplasmic tyrosine kinases.
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PMID:The cytoplasmic tyrosine kinase FER is associated with the catenin-like substrate pp120 and is activated by growth factors. 762 46

Mutations in the APC gene are linked to the development of sporadic colorectal tumors as well as to familial adenomatous polyposis. Recently, the APC protein was reported to associated with catenins, proteins that bind to the cell adhesion molecule E-cadherin. In the present study, we examined the distribution and localization of the APC protein and alpha -catenin in the normal mouse intestine by light and immunoelectron microscopy using specific antibodies. The APC protein was found to be localized in microvilli and in the apical and lateral cytoplasm of the epithelial cells, whereas alpha-catenin was detected only in the lateral cytoplasm. Double-labeling immunoelectron microscopy showed colocalization of the APC protein with alpha-catenin in the lateral cytoplasm, especially along the lateral plasma membrane, although a certain portion of the APC protein in this region was distributed independently of alpha-catenin. These results suggest that a portion of the APC protein localized in the lateral cytoplasm of intestinal epithelial cells functions in cooperation with catenins, whereas the APC protein in microvilli and in the apical cytoplasm has other functions independent of catenins.
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PMID:Subcellular localization of the APC protein: immunoelectron microscopic study of the association of the APC protein with catenin. 762 36


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