Figure 4.

A: Distribution of single molecule peaks of Lyn-PAGFP across the plasma membrane of a COS-7 cell. Peaks collected in individual frames are combined together. A sub-section of the cell, shown in the red box, is used for pair-correlation analysis. Correlation function of the distribution of peaks (black circles) could be fit to a clustered model using Eqn. 3 (red line). Correlation describing multiple appearances of a single fluorescent protein (g(r)^stoch, blue circle) was evaluated from the fit. The protein correlation function (g(r)^protein, green circles) is calculated by subtracting g(r)^stoch from the measured correlation function. Using g(r)^protein, physical parameters describing the nanoscale organization of Lyn-PAGFP could be determined. B: Distribution of cluster parameters evaluated by pair-correlation analysis of spatial distribution of Lyn-PAGFP across plasma membrane of COS-7 cells. Lyn-PAGFP is organized into clusters of 3 or more proteins, and the clusters have a wide range of sizes (60nm – >180nm). Most clusters of Lyn have increased local density ranging from 2 to > 4. Images adapted from Reference [23].