Medicine and Health Sciences Commons^™

Fret Detection Of Lymphocyte Function-Associated Antigen-1 Conformational Extension, Alexandre Chigaev, Yelena Smagley, Mark K. Haynes, Oleg Ursu, Cristian G. Bologa, Liliana Halip, Tudor Oprea, Anna Waller, Mark B. Carter, Yinan Zhang, Wei Wang, Tione Buranda, Larry A. Sklar

Pharmaceutical Sciences Faculty Publications

Lymphocyte function-associated antigen 1 (LFA-1, CD11a/CD18, αLβ2-integrin) and its ligands are essential for adhesion between T-cells and antigen-presenting cells, formation of the immunological synapse, and other immune cell interactions. LFA-1 function is regulated through conformational changes that include the modulation of ligand binding affinity and molecular extension. However, the relationship between molecular conformation and function is unclear. Here fluorescence resonance energy transfer (FRET) with new LFA-1-specific fluorescent probes showed that triggering of the pathway used for T-cell activation induced rapid unquenching of the FRET signal consistent with extension of the molecule. Analysis of the FRET quenching at rest revealed an …