Nanoscale kinetic segregation of TCR and CD45 in
engaged microvilli facilitates early T cell activation
, Yair Neve-Oz
, Julia Sajman
, Meital Reches
& Eilon Sherman
T cells have a central function in mounting immune responses. However, mechanisms of their
early activation by cognate antigens remain incompletely understood. Here we use live-cell
multi-colour single-molecule localization microscopy to study the dynamic separation
between TCRs and CD45 glycoprotein phosphatases in early cell contacts under TCR-
activating and non-activating conditions. Using atomic force microscopy, we identify these
cell contacts with engaged microvilli and characterize their morphology, rigidity and
dynamics. Physical modelling and simulations of the imaged cell interfaces quantitatively
capture the TCR–CD45 separation. Surprisingly, TCR phosphorylation negatively correlates
with TCR–CD45 separation. These data support a reﬁned kinetic-segregation model. First,
kinetic-segregation occurs within seconds from TCR activation in engaged microvilli. Second,
TCRs should be segregated, yet not removed too far, from CD45 for their optimal and
localized activation within clusters. Our combined imaging and computational approach
prove an important tool in the study of dynamic protein organization in cell interfaces.
Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel.
Institute of Chemistry, The Hebrew University, Jerusalem 91904, Israel.
Correspondence and requests for materials should be addressed to E.S. (email: firstname.lastname@example.org)