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. 2023 May 11;62(11):1735–1743. doi: 10.1021/acs.biochem.2c00712

Figure 4.

Figure 4

VIP-tagged TfR1 receptor localizes to the membrane, binds Tf, and traffics by endocytosis. CHO TRVb cells expressing VIP-tagged TfR1 were labeled live (4 °C) with 100 nM Cy5-conjugated probe peptide and 50 ng/mL Tf-488. Cells were fixed immediately after labeling (0 min) or after incubation at 37 °C to allow receptor–ligand internalization (10 min). (A) Cells expressing TfR1-PuRRRE or untagged TfR1 labeled with PunyEEER-Cy5 and Tf-488. (B) Cells expressing TfR1-PunyEEER or TfR1 labeled with PuRRRE-Cy5 and Tf-488. (C) Cells expressing TfR1-TREER or TfR1 labeled with TinyERRE-Cy5 and Tf-488. Micrographs are false-colored (Cy5, magenta; Tf-488, green; and Hoechst, blue), and green-magenta overlap appears white in the merge. The PCC between the Cy5 and 488 channels is reported in the lower left of each merge micrograph. Scale bars represent 20 μm.