Figure 2.

FAM-InsP₅ (5) is internalised by endocytosis. A) The same experiment as described in (Figure 1 A) was performed with cells that were grown to 50 % confluence, and internalisation of 5 was analysed (see Figure S3) after the time points indicated in the figure. Values shown are mean±SEM. B) H1299 cells grown to 50 % confluence were incubated with 5 for 50 min at 4 °C (upper panels) or 37 °C (lower panels). Uptake of 5 was analysed as described in Figure 1. At 4 °C, endocytosis is inhibited, and z-stack analysis (not shown) revealed that under these conditions no internalisation but only cell surface-localisation was visible (upper panel). In control cells incubated at 37 °C, z-stack analysis revealed that around 10 % of the cells had internalised 5. Representative samples of these cells are shown in the second row, with small aggregates of internalised 5 marked by arrows.