Fig. 2. Colocalization of dsRed-clathrin in Alexafluor488-transferrin puncta. (A) Alexafluor488-transferrin TIR-FM image. (B) dsRed-clathrin TIR-FM image of the same cell as in A. Spots marked by arrows contain both transferrin and clathrin. Scale bar, 5 µm. (C) The decrease of mean ± s.e.m. of correlation coefficient comparing images in A and B following pixel shift in all four directions. (D) Bar graph comparing the average clathrin fluorescence per unit area ± s.e.m. in regions within 150 transferrin puncta (50 per cell) to an equivalent number of regions outside of transferrin spots.