Juergen Behrens

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The cytoplasmic proteins beta-catenin of vertebrates and armadillo of Drosophila have two functions: they link the cadherin cell-adhesion molecules to the cytoskeleton, and they participate in the wnt/wingless signal pathway. Here we show, in a yeast two-hybrid screen, that the architectural transcription factor LEF-1 (for lymphoid enhancer-binding factor)(More)
Control of stability of beta-catenin is central in the wnt signaling pathway. Here, the protein conductin was found to form a complex with both beta-catenin and the tumor suppressor gene product adenomatous polyposis coli (APC). Conductin induced beta-catenin degradation, whereas mutants of conductin that were deficient in complex formation stabilized(More)
Activation of Wnt signaling through beta-catenin/TCF complexes is a key event in the development of various tumors, in particular colorectal and liver tumors. Wnt signaling is controlled by the negative regulator conductin/axin2/axil, which induces degradation of beta-catenin by functional interaction with the tumor suppressor APC and the serine/threonine(More)
In epithelial cells, tyrosine kinases induce the tyrosine phosphorylation and ubiquitination of the E-cadherin complex, which induces endocytosis of E-cadherin. With a modified yeast 2-hybrid system, we isolated Hakai, an E-cadherin binding protein, which we have identified as an E3 ubiquitin-ligase. Hakai contains SH2, RING, zinc-finger and proline-rich(More)
The proteins Gab1 and the related DOS (for 'daughter of sevenless') each bind to substrates of tyrosine kinases like Grb2 or Corkscrew, and act in signalling pathways downstream of tyrosine kinase receptors. Here we show that Gab1 interacts directly with the c-met-encoded receptor tyrosine kinase but not with a number of other tyrosine kinases from(More)
Plexins are widely expressed transmembrane proteins that, in the nervous system, mediate repulsive signals of semaphorins. However, the molecular nature of plexin-mediated signal transduction remains poorly understood. Here, we demonstrate that plexin-B family members associate through their C termini with the Rho guanine nucleotide exchange factors(More)
The ability of carcinomas to invade and to metastasize largely depends on the degree of epithelial differentiation within the tumors, i.e., poorly differentiated being more invasive than well-differentiated carcinomas. Here we confirmed this correlation by examining various human cell lines derived from bladder, breast, lung, and pancreas carcinomas. We(More)
beta-Catenin is involved in the formation of adherens junctions of mammalian epithelia. It interacts with the cell adhesion molecule E-cadherin and also with the tumor suppressor gene product APC, and the Drosophila homologue of beta-catenin, armadillo, mediates morphogenetic signals. We demonstrate here that E-cadherin and APC directly compete for binding(More)
Invasion and metastasis are the hallmarks of malignant tumor progression and the main cause of death in cancer. The embryonic program "epithelial-mesenchymal transition" (EMT) is thought to trigger invasion by allowing tumor cell dissemination. Here, we describe that the EMT-inducing transcriptional repressor ZEB1 promotes colorectal cancer cell metastasis(More)
It has been realized that the loss of epithelial differentiation in carcinomas, which is accompanied by higher mobility and invasiveness of the tumor cells, is often a consequence of reduced intercellular adhesion. A variety of recent reports have indicated that the primary cause for the 'scattering' of the cells in invasive carcinomas is a disturbance of(More)