Internalization and down-regulation of the ALK receptor in neuroblastoma cell lines upon monoclonal antibodies treatment |
| |
Authors: | Mazot Pierre Cazes Alex Dingli Florent Degoutin Joffrey Irinopoulou Théano Boutterin Marie-Claude Lombard Bérangère Loew Damarys Hallberg Bengt Palmer Ruth Helen Delattre Olivier Janoueix-Lerosey Isabelle Vigny Marc |
| |
Institution: | Université Pierre et Marie Curie, Paris, France. |
| |
Abstract: | Recently, activating mutations of the full length ALK receptor, with two hot spots at positions F1174 and R1275, have been characterized in sporadic cases of neuroblastoma. Here, we report similar basal patterns of ALK phosphorylation between the neuroblastoma IMR-32 cell line, which expresses only the wild-type receptor (ALK(WT)), and the SH-SY5Y cell line, which exhibits a heterozygous ALK F1174L mutation and expresses both ALK(WT) and ALK(F1174L) receptors. We demonstrate that this lack of detectable increased phosphorylation in SH-SY5Y cells is a result of intracellular retention and proteasomal degradation of the mutated receptor. As a consequence, in SH-SY5Y cells, plasma membrane appears strongly enriched for ALK(WT) whereas both ALK(WT) and ALK(F1174L) were present in intracellular compartments. We further explored ALK receptor trafficking by investigating the effect of agonist and antagonist mAb (monoclonal antibodies) on ALK internalization and down-regulation, either in SH-SY5Y cells or in cells expressing only ALK(WT). We observe that treatment with agonist mAbs resulted in ALK internalization and lysosomal targeting for receptor degradation. In contrast, antagonist mAb induced ALK internalization and recycling to the plasma membrane. Importantly, we correlate this differential trafficking of ALK in response to mAb with the recruitment of the ubiquitin ligase Cbl and ALK ubiquitylation only after agonist stimulation. This study provides novel insights into the mechanisms regulating ALK trafficking and degradation, showing that various ALK receptor pools are regulated by proteasome or lysosome pathways according to their intracellular localization. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|