Figure 2.

Codependent distribution of GFP-Mid1 and FLAG-α4. (a) COS7 cells were fixed and stained with anti-α4 antibodies to show the distribution of the endogenous α4 protein in a nontransfected cell (first frame) and in a cell expressing GFP-Mid1 (second frame). The distribution of GFP-Mid1 itself is shown in green, and colocalization of GFP-Mid1 and endogenous α4 is shown in yellow in the merged image (fourth frame). (b) COS7 cells were cotransfected to express both GFP-Mid1 and FLAG-α4. Cells were fixed and GFP-Mid was visualized by direct fluorescence microscopy, and FLAG-α4 was stained as described. From multiple experiments, representative cells with increasing levels of FLAG-α4 (columns 1, 2, and 3, left to right) were compared for localization of FLAG-α4 and GFP-Mid1. In the merged images, nuclei were stained by DAPI. (c) Cells expressing both GFP-Mid1 and FLAG-α4 to give foci of GFP-Mid1 (green) were fixed and stained for β-tubulin (red) and DAPI (blue).