Direction of actin flow dictates integrin LFA-1 orientation during leukocyte migration

• Published in: Nature communications 2017-12, Vol.8 (1), p.2047-16, Article 2047
• Main Authors: Nordenfelt, Pontus, Moore, Travis I., Mehta, Shalin B., Kalappurakkal, Joseph Mathew, Swaminathan, Vinay, Koga, Nobuyasu, Lambert, Talley J., Baker, David, Waters, Jennifer C., Oldenbourg, Rudolf, Tani, Tomomi, Mayor, Satyajit, Waterman, Clare M., Springer, Timothy A.
• Format: Article
• Language: English
• Subjects: 631/1647/245/2160; 631/1647/328/1652; 631/80/128/1276; 631/80/79/1236; 631/80/84/2342; Actin; Actin Cytoskeleton - metabolism; Actins - metabolism; Adhesion tests; Amino Acid Sequence; Atomic structure; Basic Medicine; Binding; Cell adhesion; Cell adhesion & migration; Cell Membrane - metabolism; Cell Movement; Cell surface; Cytoskeleton; Fluorescence; Fluorescence polarization; Fluorescence Polarization - methods; Glycoproteins; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; HEK293 Cells; Humanities and Social Sciences; Humans; Immunologi inom det medicinska området; Immunology in the medical area; Integrins; Jurkat Cells; Leukocyte migration; Leukocytes; Leukocytes - cytology; Leukocytes - metabolism; LFA-1 antigen; Ligands; Lymphocyte Function-Associated Antigen-1 - genetics; Lymphocyte Function-Associated Antigen-1 - metabolism; Medical and Health Sciences; Medicin och hälsovetenskap; Medicinska och farmaceutiska grundvetenskaper; Microscopy; Microscopy, Fluorescence - methods; multidisciplinary; Orientation; Protein Binding; Receptors; Science; Science (multidisciplinary); Sequence Homology, Amino Acid
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-017-01848-y

Integrin αβ heterodimer cell surface receptors mediate adhesive interactions that provide traction for cell migration. Here, we test whether the integrin, when engaged to an extracellular ligand and the cytoskeleton, adopts a specific orientation dictated by the direction of actin flow on the surface of migrating cells. We insert GFP into the rigid, ligand-binding head of the integrin, model with Rosetta the orientation of GFP and its transition dipole relative to the integrin head, and measure orientation with fluorescence polarization microscopy. Cytoskeleton and ligand-bound integrins orient in the same direction as retrograde actin flow with their cytoskeleton-binding β-subunits tilted by applied force. The measurements demonstrate that intracellular forces can orient cell surface integrins and support a molecular model of integrin activation by cytoskeletal force. Our results place atomic, Å-scale structures of cell surface receptors in the context of functional and cellular, μm-scale measurements. Integrin αβ heterodimer cell surface receptors mediate adhesive interactions that provide traction for cell migration. Here the authors show that actin flow can orient cell surface integrins during leukocyte migration, suggesting integrin activation by cytoskeletal force.