Hotspots of GPI-anchored proteins and integrin nanoclusters function as nucleation sites for cell adhesion
Open Access
- 3 November 2009
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 106 (44), 18557-18562
- https://doi.org/10.1073/pnas.0905217106
Abstract
Recruitment of receptor proteins to lipid rafts has been proposed as an important mechanism to regulate their cellular function. In particular, rafts have been implicated in regulation of integrin-mediated cell adhesion, although the underlying mechanism remains elusive. We used single-molecule near-field optical microscopy (NSOM) with localization accuracy of approximately 3 nm, to capture the spatio-functional relationship between the integrin LFA-1 and raft components (GPI-APs) on immune cells. Dual color nanoscale imaging revealed the existence of a nanodomain GPI-AP subpopulation that further concentrated in regions smaller than 250 nm, suggesting a hierarchical prearrangement of GPI-APs on resting monocytes. We previously demonstrated that in quiescent monocytes, LFA-1 preorganizes in nanoclusters. We now show that integrin nanoclusters are spatially different but reside proximal to GPI-AP nanodomains, forming hotspots on the cell surface. Ligand-mediated integrin activation resulted in an interconversion from monomers to nanodomains of GPI-APs and the generation of nascent adhesion sites where integrin and GPI-APs colocalized at the nanoscale. Cholesterol depletion significantly affected the reciprocal distribution pattern of LFA-1 and GPI-APs in the resting state, and LFA-1 adhesion to its ligand. As such, our data demonstrate the existence of nanoplatforms as essential intermediates in nascent cell adhesion. Since raft association with a variety of membrane proteins other than LFA-1 has been documented, we propose that hotspots regions enriched with raft components and functional receptors may constitute a prototype of nanoscale inter-receptor assembly and correspond to a generic mechanism to offer cells with privileged areas for rapid cellular function and responses to the outside world.This publication has 33 references indexed in Scilit:
- Monomer–dimer dynamics and distribution of GPI-anchored uPAR are determined by cell surface protein assembliesThe Journal of cell biology, 2007
- Tether and trap: regulation of membrane-raft dynamics by actin-binding proteinsNature Reviews Immunology, 2007
- Nanoscale Organization of the Pathogen Receptor DC‐SIGN Mapped by Single‐Molecule High‐Resolution Fluorescence MicroscopyChemphyschem, 2007
- GPI-anchored receptor clusters transiently recruit Lyn and Gα for temporary cluster immobilization and Lyn activation: single-molecule tracking study 1The Journal of cell biology, 2007
- Structural Basis of Integrin Regulation and SignalingAnnual Review of Immunology, 2007
- Organization of the Integrin LFA-1 in Nanoclusters Regulates Its ActivityMolecular Biology of the Cell, 2006
- Dynamics in the plasma membrane: how to combine fluidity and orderThe EMBO Journal, 2006
- Dynamic Partitioning into Lipid Rafts Controls the Endo-Exocytic Cycle of the αL/β2Integrin, LFA-1, during Leukocyte ChemotaxisMolecular Biology of the Cell, 2005
- Near‐field scanning optical microscopy in liquid for high resolution single molecule detection on dendritic cellsFEBS Letters, 2004
- Precise Nanometer Localization Analysis for Individual Fluorescent ProbesBiophysical Journal, 2002