CDB15:0000978 LAMA1 — ITGA6
Experimentally validated in Human, Mixed species; Orthology-inferred in Human, Mouse, Rat, Frog, Zebrafish, Chicken, Macaque, Pig, Dog, Cow, Chimp, Horse, Marmoset, Sheep
Title
Journal:; Year Published:
Abstract
A cell-free electrochemiluminescence assay for measuring beta1-integrin-ligand interactions.
Analytical biochemistry, 2002; PubMed, Mus Musculus Lama1 — Homo sapiens ITGA6
ABSTRACT: We have developed a cell-free assay for binding of solubilized beta1 integrins to their physiologically relevant ligands using an electrochemiluminescent detection method. The method utilizes ruthenium-conjugated monoclonal antibodies for detection of either purified integrins or, more conveniently, integrin-expressing cell lysates, which are captured on beads coated with extracellular matrix or vascular ligand proteins. For the interaction of alpha1beta1 integrin with collagen IV, a signal of 10-fold over background was generated with samples containing only 10 ng (0.05 pmol) of integrin. This interaction is cation-dependent and can be inhibited by blocking antibodies to the alpha1 subunit. The method was extended to studies of ligand binding by integrins alpha2beta1, alpha4beta1, alpha5beta1, and alpha6beta1. For each integrin-ligand pair, the specificity of the interaction was verified with neutralizing antibodies against the specific integrin. The specific binding signal correlated with the activating ability of the labeled antibody used for detection, although the ability of divalent cations (Mn2+, Mg2+, Ca2+) to support integrin-ligand binding varied dramatically among the various integrin-ligand pairs. The assay provides a simple method for investigating integrin-ligand interactions without avidity and/or signaling effects which can complicate conventional cell-based assay methods.
Integrin alpha 6 beta 4 mediates dynamic interactions with laminin.
Journal of cell science, 1994; PubMed, Homo sapiens LAMA1 — Homo sapiens ITGA6
ABSTRACT: We present here a novel form of dynamic adhesion in which both the integrin receptor and the ligand supporting dynamic adhesion have been identified. Laminar flow assays showed that laminin supported attachment of alpha 6 beta 4-positive cells in the presence of fluid shear stress (tau < or = 2 dyn/cm2), indicating that these cells adhered to laminin within a fraction of a second. Further increases in flow rate (3.5 dyn/cm2 < or = tau < or = 100 dyn/cm2) initiated rolling of attached cells in the direction of flow, suggesting that rapidly formed adhesion is reversible and repeatable. Laminin fragment E8, which interacts with alpha 6 integrins, supported dynamic attachment and rolling but extracellular matrix glycoprotein fibronectin did not. In cell lines that express alpha 6 beta 4 but not alpha 6 beta 1 an anti-alpha 6 monoclonal antibody inhibited attachment to laminin in the presence of flow and following 5 minutes of static incubation. Infusion of this antibody onto cells adherent to laminin-coated slides led to rapid detachment of cells from the substratum. An anti-beta 1 monoclonal antibody diminished adhesion strength following static incubation but did not inhibit rapid attachment and flow-initiated rolling. These results indicate that in some alpha 6 beta 4-expressing epithelial and carcinoma cell lines, integrin alpha 6 beta 4 mediates rapidly formed dynamic interactions with laminin.