Fig. 2

Apo- and holo-Tf interactions with Fpn and Heph. HEK 293 cells were transfected with HA-tagged Fpn and subsequently incubated with 0.25 μM apo- or holo-Tf for 10 min. Immunoprecipitate (IP) and 50% of cell lysate (input) was processed for immunoblotting. Co-IP of HA-Fpn shows that both apo- and holo-Tf are pulled down along with the Fpn complex (A). Co-IP of Heph in iPSC-derived ECs replicated these data (B). HEK 293 cells were used to determine direct protein interactions using PLA, reported as integrated density per cell in the field of view per image. Holo-Tf interacts with Fpn (D), while apo-Tf does not (C). Alternatively, apo-Tf interacts with Heph (F), while holo-Tf does not (G). n = 4 for all experiments, means of biological replicates ± SEM were evaluated for statistical significance using unpaired t test. ***p < 0.001, ****p < 0.0001