Two conformations of the integrin A-domain (I-domain): a pathway for activation?
Lee, J.O., Bankston, L.A., Arnaout, M.A., Liddington, R.C.(1995) Structure 3: 1333-1340
- PubMed: 8747460 
- DOI: https://doi.org/10.1016/s0969-2126(01)00271-4
- Primary Citation of Related Structures:  
1JLM - PubMed Abstract: 
Integrins are plasma membrane proteins that mediate adhesion to other cells and to components of the extracellular matrix. Most integrins are constitutively inactive in resting cells, but are rapidly and reversibly activated in response to agonists, leading to highly regulated cell adhesion. This activation is associated with conformational changes in their extracellular portions, but the nature of the structural changes that lead to a change in adhesiveness is not understood. The interactions of several integrins with their extracellular ligands are mediated by an A-type domain (generally called the I-domain in integrins). Binding of the I-domain to protein ligands is dependent on divalent cations. We have described previously the structure of the I-domain from complement receptor 3 with bound Mg2+, in which the glutamate side chain from a second I-domain completes the octahedral coordination sphere of the metal, acting as a ligand mimetic.
Organizational Affiliation: 
Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.