IGF-1 receptor activity in the Golgi of migratory cancer cells depends on adhesion-dependent phosphorylation of Tyr1250 and Tyr1251
American Association for the Advancement of Science
Although insulin-like growth factor 1 (IGF-1) signaling promotes tumor growth and cancer progression, therapies that target the IGF-1 receptor (IGF-1R) have shown poor clinical efficacy. To address IGF-1R activity in cancer cells and how it differs from that of the closely related insulin receptor (IR), we focused on two tyrosines in the IGF-1R C-terminal tail that are not present in the IR and are essential for IGF-1–mediated cancer cell survival, migration, and tumorigenic growth. We found that Tyr1250 and Tyr1251 (Tyr1250/1251) were autophosphorylated in a cell adhesion–dependent manner. To investigate the consequences of this phosphorylation, we generated phosphomimetic Y1250E/Y1251E (EE) and nonphosphorylatable Y1250F/Y1251F (FF) mutant forms of IGF-1R. Although fully competent in kinase activity and signaling, the EE mutant was more rapidly internalized and degraded than either the wild-type or FF receptor. IGF-1 promoted the accumulation of wild-type and EE IGF-1R within the Golgi apparatus, whereas the FF mutant remained at the plasma membrane. Golgi-associated IGF-1R signaling was a feature of migratory cancer cells, and Golgi disruption impaired IGF-1–induced signaling and cell migration. Upon the formation of new cell adhesions, IGF-1R transiently relocalized to the plasma membrane from the Golgi. Thus, phosphorylation at Tyr1250/1251 promoted IGF-1R translocation to and signaling from the Golgi to support an aggressive cancer phenotype. This process distinguishes IGF-1R from IR signaling and could contribute to the poor clinical efficacy of antibodies that target IGF-1R on the cell surface.
Insulin-like growth factor 1 , IGF-1 , IGF-1R , Tyrosine , Tyr1250 , Tyr1251 , Tyr1250/1251 , Cell adhesion , Cancer , Tumor , Golgi
Rieger, L., O’Shea, S., Godsmark, G., Stanicka, J., Kelly, G. and O’Connor, R. (2020) ‘IGF-1 receptor activity in the Golgi of migratory cancer cells depends on adhesion-dependent phosphorylation of Tyr1250 and Tyr1251’, Science Signaling, 13(633), eaba3176. doi: 10.1126/scisignal.aba3176
© 2020, the Authors. Published under license by the American Association for the Advancement of Science. This is the author’s version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science Signaling 13(633) on 26 May 2020, doi: 10.1126/scisignal.aba3176