First, monitoring of kinetics of intracellular accumulation demonstrated that probe internalization was completed in about 3 6 h (see Ir1 data in Figure 3).
Therefore, the initial point at which the FITC/InlA-bead intensity drops is expected to be a reasonably accurate measure, albeit less precise than the static bead measurements using Alexa488 quencher antibodies presented earlier, of the time when internalization is complete (Figure 4A – green arrow).
Internalization was complete after 30 minutes at 37°C.
When internalization occurred, it was completed by 60 min and the number of vesicles was counted manually at 30 to 46 different time points in images extracted from recorded videos.
In AR42J tumors transplanted in Lewis rats, internalization was fast (within 10 min) and recycling was completed within 24 h after administration of the somatostatin analog ([Tyr3, Thr8]-octreotide, TATE) [36].
Comparing cells treated with IL-1 and IL-1 + UVB, respectively, revealed IL-1R internalization to follow almost identical kinetics, starting very early after 5 min and being completed latest after 60 min, indicating changes of IL-1R internalization to be irresponsible for prolonged IKKβ phosphorylation.
Only small increases in internalized ligand were observed at 1 h and 2 h, suggesting ligand internalization is nearly complete by 30 minutes.
Simply speaking, there was a huge prokaryotic biomass to be harvested by predators, and few would doubt that complete internalization is more efficient then external digestion and osmotrophy.
The complete route of syndecan-1 internalization is not yet elucidated, but it is known that the nuclear translocation of syndecan-1 is tubulin-dependent [ 97].
This fundamental process of internalization is called gastrulation.
