Aggregation of PDGF‐β receptors in human skin fibroblasts: characterization by image correlation spectroscopy (ICS)

Abstract

Receptor aggregation is believed to be an important, early step when growth factors such as PDGF stimulate proliferation and differentiation of cell populations. To investigate receptor aggregation, we utilized a novel biophysical technique, image correlation spectroscopy, to study the distribution and aggregation state of PDGF-ß receptors on the surface of human dermal fibroblasts under various experimental conditions. It was found that the cell surface receptors were pre-clustered at 4°C and receptor aggregation increased for samples measured at 37°C. Treatment with PDGF-BB had no measurable effect on the receptor aggregation state. The results also indícate that additions of 10% serum or an inhibitor of tyrosine kinase activity, may disperse the receptors. The results of this study are consistent with organization of PDGF-ß receptors in pre-existing membrane domains.

Advances in Image Correlation Spectroscopy: Measuring Number Densities, Aggregation States, and Dynamics of Fluorescently labeled Macromolecules in Cells

“…If the protein of interest is labeled with GFP, c can be found by imaging a control sample of dispersed GFP monomers under identical conditions as the regular samples [4]. Since the DA is calculated from an image, it can be calculated as a function of time from an image series to measure changes in the aggregation state of a protein [4,24].…”

Dynamics and interaction of caveolin-1 isoforms with BMP-receptors

“…Image correlation spectroscopy Image Correlation Spectroscopy (ICS) and Image Cross-Correlation Spectroscopy are two techniques that can be used to study the distribution and localization of receptors (Brown and Petersen, 1998;Srivastava and Petersen, 1998;Wiseman and Petersen, 1999;Wiseman et al, 1997). ICS involves autocorrelation-analysis of the intensity-fluctuations within collected confocal images, in this case, of transfected cells that contain immunofluorescently labeled proteins.…”

Effect of the distribution and clustering of the type I A BMP receptor(ALK3) with the type II BMP receptor on the activation of signalling pathways

“…It is also known that for homogenous, non-interacting species, where the intensity is a true representation of the concentration, the variance of the normalised intensity fluctuations is equal to the variance of the concentration fluctuations, which in turn is equal to the inverse of the number of particles in the observation area, N -p (Wiseman et al, 1997). Once the g(0,0) is known, an important parameter, called the cluster density (CD), can be calculated.…”

“…In order to understand the details of this process we need to study the quantitative distribution of the BMP receptors and the changes in their distribution following BMP-2 stimulation. Image correlation spectroscopy (ICS) provides a convenient and quantitative tool to measure the density of receptor clusters on cell surfaces (Brown and Petersen 1998;Brown et al, 1999;Srivastava and Petersen 1998;Wiseman and Petersen 1999;Wiseman et al, 1997).…”