Related Experiment Video
Updated: May 18, 2026

Tension Gauge Tether Probes for Quantifying Growth Factor Mediated Integrin Mechanics and Adhesion
Published on: February 11, 2022
Unraveling the role of membrane proteins Notch, Pvr, and EGFR in altering integrin diffusion and clustering
Neha Arora1, Dipak Mainali, Emily A Smith
1Department of Chemistry, Iowa State University, Ames, IA 50011, USA.
Abstract:
The role of three membrane proteins in altering the diffusion and clustering of integrin receptors has been measured. Integrins are membrane proteins responsible for integrating intracellular and extracellular signaling events and anchoring cells to the extracellular matrix. The methodology used to elucidate the role of other membrane proteins in altering integrin diffusion and clustering combines fluorescence microscopy with RNA interference (RNAi), which is a technique to reduce the expression of a target protein. The three RNAi-targeted membrane proteins were epidermal growth factor receptor (EGFR), platelet-derived growth factor/vascular endothelial growth factor-related receptor (Pvr), and Notch. Real-time polymerase chain reaction or quantitative immunocytochemistry was used to measure a reduction in mRNA or protein concentration after RNAi treatment, respectively. Fluorescence recovery after photobleaching showed that reducing the concentration of EGFR or Notch results in less constrained integrin diffusion and, in the case of Notch RNAi, 4 % more mobile integrins. Fluorescence resonance energy transfer measurements performed before and after RNAi treatments indicate that clustering decreases for wild-type integrin, but increases for a high-ligand-affinity integrin mutant after reducing the expression of EGFR, Pvr, or Notch. A model to explain the measured changes after reducing the expression of these three membrane proteins involving cholesterol-enriched nanodomains is proposed.
Related Concept Videos
Intracellular Signaling Affects Focal Adhesions
Some...
Activation of Integrins
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
Integrins
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
Notch Signaling Pathway
The Notch gene came into the limelight in 1914 after the discovery that its mutation in Drosophila melanogaster leads to a serrated (or "notched") wing margin phenotype. It was not until 1985...
Protein Diffusion in the Membrane
Overview of Cell-Matrix Interactions

