Figure 5.

Ligand-induced internalization of GFP-tagged endocytosis-defective receptors depends on the presence of wild-type receptors. Cultures were treated with cycloheximide and α-factor as described in Figure 3. First two columns are controls lacking α-factor; the last two columns are α-factor–treated cells. GFP fluorescence images and Nomarski images are indicated below each column. Top row, cells expressing Ste2-GFP only (strain DJ1413-A). Middle row, cells expressing Ste2-T326-GFP only (strain DJ1410-A). Bottom row, cells expressing both Ste2-T326-GFP and untagged Ste2 (strain DJ1411-A).