Structural and functional characterization of integrin αLβ2.
Date of Issue2011
School of Biological Sciences
Integrins are adhesion molecules that transmit bidirectional signals across the plasma membrane by undergoing extensive structural changes. The focus of this thesis is the leukocyte-restricted integrin αLβ2 (Leukocyte-function associated antigen -1, LFA-1; CD11a/CD18). The first part of this thesis examined the conformational requirements of αLβ2 to bind ligands intercellular adhesion molecule -1 (ICAM-1) and ICAM-3. Effective migration of cells on substrate requires coordinated attachment at the leading edge and the detachment of its rear. Conceivably, de-adhesion of integrins at the rear of the migrating cell plays an important role in cell locomotion. The second part of this study examines molecules that could be involved in the αLβ2 de-adhesion process. The cytoplasmic tails play important role in regulating the activity and signaling capacity of integrins. There are many structural studies on the cytoplasmic tails of platelet integrin αIIbβ3, but very little is known of other integrin cytoplasmic tails. The third part of this thesis examines the solution conformations and interactions of the αLβ2 cytoplasmic tails by nuclear magnetic resonance (NMR) analyses.