Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.3.5.1 (succinate dehydrogenase)
 8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Catenins are cytoplasmic proteins that were initially identified in a complex with cadherins, a superfamily of transmembrane glycoproteins important for cell adhesion in normal and disease states. We have used gel filtration to identify four complexes of catenins in extracts from normal and transformed epithelial cells. In normal Madin-Darby canine kidney epithelial cells, a significant fraction of alpha- and beta-catenin and plakoglobin co-elute with cadherin in a high molecular weight complex (complex I). A portion of alpha-catenin and the remainder of beta-catenin and plakoglobin co-elute in a high molecular weight complex that does not contain cadherin (complex II). The remainder of alpha-catenin elutes in a low molecular weight fraction (complex III). In extracts from two colon carcinoma cell lines, HCT116 and SW480, beta-catenin elutes in an additional low molecular weight pool (complex IV) not present in Madin-Darby canine kidney cell extracts. In two subclones derived from SW480 cells, SW-E8 and SW-R2, beta-catenin is distributed evenly between high and low molecular weight pools in SW-E8 cells, whereas it elutes primarily in the low molecular weight pool (complex IV) in SW-R2 cells. These changes in beta-catenin elution profiles correlate with an increase in transformed phenotype and decreased cell-cell adhesion in the SW-R2 cells.
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PMID:Identification of four distinct pools of catenins in mammalian cells and transformation-dependent changes in catenin distributions among these pools. 936 32

When epithelial cells reach confluency in vitro, a number of energy-requiring activities such as growth and motility are contact-inhibited. We investigated the possible role of the E-cadherin/catenin complex, which acts as an invasion suppressor, in contact inhibition. Three strategies for modulation of the complex were used. Firstly, the cell-cell adhesion and signal transduction functions of E-cadherin were neutralized immunologically in human MCF-7/6 mammary carcinoma cells possessing a complete complex. Secondly, the effect of E-cadherin transfection in E-cadherin negative cell lines was investigated. Thirdly, alpha-catenin deficient variants of the human HCT-8/S11 colon carcinoma cell line were compared with their parent cells. In confluent cultures functional downregulation of the E-cadherin/catenin complex did not alter cell growth nor saturation density. This was shown by cell number counts, protein staining assays, cell cycle analysis, proliferation markers (Ki67 and Proliferating Cell Nuclear Antigen) and apoptosis assays. However, confluent cells with a functionally deficient complex showed positional instability and enhanced succinate dehydrogenase-mediated mitochondrial 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyl) tetrazolium bromide (MTT) conversion, as compared to cells with an active complex. Our data indicate that contact inhibition of motility and of mitochondrial enzyme activity, but not of growth is regulated by the E-cadherin/catenin complex in epithelial cells.
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PMID:Functional downregulation of the E-cadherin/catenin complex leads to loss of contact inhibition of motility and of mitochondrial activity, but not of growth in confluent epithelial cell cultures. 943 30