![]() ![]() Kreis, Stephanie ![]() in Experimental Cell Research (2005), 305(1), 110-121 Integrin receptors are crucial players in cell adhesion and migration. Identification and characterization of cellular proteins that interact with their short α and β cytoplasmic tails will help to ... [more ▼] Integrin receptors are crucial players in cell adhesion and migration. Identification and characterization of cellular proteins that interact with their short α and β cytoplasmic tails will help to elucidate the molecular mechanisms by which integrins mediate bi-directional signaling across the plasma membrane. Integrin α2β1 is a major collagen receptor but to date, only few proteins have been shown to interact with the α2 cytoplasmic tail or with the α2β1 complex. In order to identify novel binding partners of a α2β1cytoplasmic domain complex, we have generated recombinant GST-fusion proteins, incorporating the leucine zipper heterodimerization cassettes of Jun and Fos. To ascertain proper functionality of the recombinant proteins, interaction with natural binding partners was tested. GST-α2 and GST-Jun α2 bound His-tagged calreticulin while GST-β1 and GST-Fos β1 proteins bound talin. In screening assays for novel binding partners, the immobilized GST-Jun α2/GST-Fos β1 heterodimeric complex, but not the single subunits, interacted specifically with endothelial cell-derived vimentin. Vimentin, an abundant intermediate filament protein, has previously been shown to co-localize with αvβ3-positive focal contacts. Here, we provide evidence that this interaction also occurs with α2β1-enriched focal adhesions and we further show that this association is lost after prolonged adhesion of endothelial cells to collagen. © 2005 Elsevier Inc. All rights reserved. [less ▲] Detailed reference viewed: 100 (5 UL)![]() ![]() ; Kreis, Stephanie ![]() in Biochimica et Biophysica Acta-Gene Structure and Expression (2002), 1575(1-3), 117-122 Integrin-linked kinase (ILK)-1 is a 59-kDa serine-threonine protein kinase, which associates with the cytoplasmic domain of β1, β2 and β3 integrins and acts as a receptor proximal kinase regulating ... [more ▼] Integrin-linked kinase (ILK)-1 is a 59-kDa serine-threonine protein kinase, which associates with the cytoplasmic domain of β1, β2 and β3 integrins and acts as a receptor proximal kinase regulating integrin-mediated signal transduction. We have recently identified an isoform of ILK (ILK-2), which is expressed, in a TGF-β1-dependent manner, in a highly invasive tumor cell line but not in normal adult tissues. In contrast, ILK-1 is ubiquitously expressed in normal tissues and is up-regulated in various tumors independent of TGF-β1. Here, we report the structural organization and the promoter activity of the human ILK-1 gene, contained within a 8.8-kb genomic fragment cloned from a human BAC library. The mature protein is encoded by 13 exons. The last coding exon contains the entire 3′ UTR of the ILK-1 gene, which overlaps with the complementary 3′ UTR sequence of the TAF2H gene, a TATA box binding protein-associated factor. A major transcriptional initiation start site was found 138 bp upstream of exon 1 in close proximity to a consensus initiator element (Inr). The ILK gene is transcribed by a TATA-less and CAAT-less promoter with typical features of housekeeping genes. The promoter activity was characterized by a luciferase reporter assay and the minimal sequence conferring promoter activity was 349 bp in size and located immediately upstream of exon 1. © 2002 Elsevier Science B.V. All rights reserved. [less ▲] Detailed reference viewed: 107 (8 UL) |
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