RT Journal Article
SR Electronic
T1 Direction of actin flow dictates integrin LFA-1 orientation during leukocyte migration
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 071936
DO 10.1101/071936
A1 Pontus Nordenfelt
A1 Travis I. Moore
A1 Shalin B. Mehta
A1 Joseph Mathew Kalappurakkal
A1 Vinay Swaminathan
A1 Nobuyasu Koga
A1 Talley J. Lambert
A1 David Baker
A1 Jennifer C. Waters
A1 Rudolf Oldenbourg
A1 Tomomi Tani
A1 Satyajit Mayor
A1 Clare M. Waterman
A1 Timothy A. Springer
YR 2017
UL http://biorxiv.org/content/early/2017/01/19/071936.abstract
AB Integrin αβ heterodimer cell surface receptors mediate adhesive interactions that provide traction for cell migration. Here, we test whether the integrin head, known from crystal structures, adopts a specific orientation dictated by the direction of actin flow on the surface of migrating cells. We insert GFP into the rigid head of the full integrin, model with Rosetta the orientation of GFP and its transition dipole relative to the integrin, and measure orientation with fluorescence polarization microscopy. Dependent on coupling to the cytoskeleton, 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. We have developed a method that places atomic, ~Å structures of cell surface receptors in the context of functional, cellular length-scale, ~μm measurements and shows that rotation and tilt of cell surface receptors relative to the membrane plane can be restrained by interactions with other cellular components.