Integrin-mediated adhesion promotes cell survival in vitro, whereas integrin antagonists induce apoptosis of adherent cells in vivo. Here, we demonstrate that cells adherent within a three-dimensional extracellular matrix undergo apoptosis due to expression of unligated integrins, the beta subunit cytoplasmic domain, or its membrane proximal sequence KLLITIHDRKEF. Integrin-mediated death requir...

Integrins mediate cell adhesion and signal transduction at focal adhesions. Here we investigate the roles of integrin beta subunits in the regulation of actin cytoskeletal structure and the activities of Rho and Rac. The overexpression of beta3 integrin in Chinese hamster ovary cells enhances Rho activity and stress fiber formation, whereas the overexpression of beta1 integrin increases Rac act...

Squamous cell carcinoma of the oral cavity is characterized by persistent, disorganized expression of integrin alpha3beta1 and enhanced production of urinary-type plasminogen activator (uPA) and its receptor (uPAR) relative to normal oral mucosa. Because multivalent aggregation of alpha3beta1 integrin up-regulates uPA and induces a dramatic co-clustering of uPAR, we explored the hypothesis that...

Mast cells (MCs) are centrally important in allergic inflammation of the airways, as well as in the intestinal immune response to helminth infection. A single lineage of bone marrow (BM)-derived progenitors emigrates from the circulation and matures into phenotypically distinct MCs in different tissues. Because the mechanisms of MC progenitor (MCp) homing to peripheral tissues have not been eva...

CD151, a member of the tetraspanin family of proteins, forms a stable complex with integrin alpha 3 beta 1 and regulates integrin-mediated cell-substrate adhesion. However, the molecular basis of the stable association of CD151 with integrin alpha 3 beta 1 remains poorly understood. In the present study, we show that a panel of anti-human CD151 mAbs (monoclonal antibodies) could be divided into...

E-cadherin loss is frequently associated with ovarian cancer metastasis. Given that adhesion to the abdominal peritoneum is the first step in ovarian cancer dissemination, we reasoned that down-regulation of E-cadherin would affect expression of cell matrix adhesion receptors. We show here that inhibition of E-cadherin in ovarian cancer cells causes up-regulation of alpha(5)-integrin protein ex...

In this study, we have examined the spatiotemporal distribution of the alpha 1 integrin subunit, a putative laminin and collagen receptor, in avian embryos, using immunofluorescence microscopy and immunoblotting techniques. We used an antibody raised against a gizzard 175 x 10(3) M(r) membrane protein which was described previously and which we found to be immunologically identical to the chick...

Integrin signaling impacts many developmental processes. The complexity of these signals increases when multiple, unique integrin heterodimers are expressed during a single developmental event. Since integrin heterodimers have different signaling capabilities, the signals originating at each integrin type must be separated in the cell. C. elegans have two integrin heterodimers, α INA-1/β PAT-3 ...