Fig. 4. Disruption of microtubule-organizing centers in cells expressing mutant GH. Cells cotransfected with wt-GH or 32-71-GH were stained with antibody to -tubulin (left panels) and antibody to GH (middle panels). Right panels show GH in red and -tubulin in green; colocalized staining appears yellow. Microtubule polymers can be seen emanating from distinct microtubule-organizing centers in cells expressing wt-GH, which is concentrated in the Golgi apparatus, and in cells not expressing any GH. The lower panels show that 32-71-GH is retained in the ER, and cells expressing 32-71-GH show no distinct microtubule organizing centers.