McDermott Niamh, O'Shea Stephen, Rieger Leonie, Cox Orla T, O'Connor Rosemary
Cell Biology Laboratory, School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland.
Cell Biology Laboratory, School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland.
J Biol Chem. 2025 Jan;301(1):108021. doi: 10.1016/j.jbc.2024.108021. Epub 2024 Nov 27.
Cell adhesion-dependent phosphorylation of insulin-like growth factor 1 receptor (IGF-1R) on its C-terminal tail (CT) at Tyr promotes receptor internalization and Golgi accumulation. We previously proposed that this phosphorylation is associated with cell migration and cancer aggressiveness, distinguishing IGF-1R activity from that of insulin receptor, which lacks these tyrosines. Here, we further investigated how adhesion signaling influences IGF-1R location and activity in migratory cancer cells and R- fibroblasts. We observed that IGF-1R, in triple-negative breast cancer tissues, is predominantly intracellular and dispersed from the plasma membrane compared with nontumor tissue. Datasets from basal-like breast cancer patients indicated a strong, positive correlation between IGF-1R protein expression and that of β-integrin (ITGB1). In triple-negative breast cancer cells with high ITGB1 expression, suppressing ITGB1 enhanced IGF-1R stability and its retention at the plasma membrane, and reduced IGF-1R internalization during cell adhesion. In R- fibroblasts, we observed reduced IGF-1R autophosphorylation and Golgi accumulation when ITGB1 was suppressed. The stability of a TyrPhe (FF) IGF-1R mutant was less affected by ITGB1 suppression, indicating that Tyr phosphorylation is required for ITGB1-enhanced receptor internalization. Furthermore, a TyrGlu (EE) IGF-1R mutant exhibited a gain of cell migration and colony formation potential compared to WT IGF-1R or FF mutant. Tyr resides within the CT SFYYS motif, which engages the IGF-1R kinase domain. In silico, we investigated how mutation of these tyrosines may alter SFYYS conformation, dictating trajectory of the distal CT. We conclude that Tyr phosphorylation confers IGF-1R with unique protumorigenic signaling in a manner that is enhanced by ITGB1.
胰岛素样生长因子1受体（IGF-1R）C末端尾巴（CT）上酪氨酸的细胞黏附依赖性磷酸化促进受体内化和高尔基体积累。我们之前提出，这种磷酸化与细胞迁移和癌症侵袭性相关，将IGF-1R的活性与缺乏这些酪氨酸的胰岛素受体的活性区分开来。在这里，我们进一步研究了黏附信号如何影响迁移癌细胞和R-成纤维细胞中IGF-1R的定位和活性。我们观察到，与非肿瘤组织相比，三阴性乳腺癌组织中的IGF-1R主要位于细胞内且从质膜分散。基底样乳腺癌患者的数据集表明，IGF-1R蛋白表达与β-整合素（ITGB1）的蛋白表达之间存在强烈的正相关。在ITGB1高表达的三阴性乳腺癌细胞中，抑制ITGB1可增强IGF-1R的稳定性及其在质膜的保留，并减少细胞黏附过程中IGF-1R的内化。在R-成纤维细胞中，我们观察到抑制ITGB1时IGF-1R的自磷酸化和高尔基体积累减少。酪氨酸苯丙氨酸（FF）IGF-1R突变体的稳定性受ITGB1抑制的影响较小，表明酪氨酸磷酸化是ITGB1增强受体内化所必需的。此外，与野生型IGF-1R或FF突变体相比，酪氨酸谷氨酸（EE）IGF-1R突变体表现出细胞迁移和集落形成潜力的增加。酪氨酸位于CT SFYYS基序内，该基序与IGF-1R激酶结构域结合。在计算机模拟中，我们研究了这些酪氨酸的突变如何改变SFYYS构象，从而决定远端CT的轨迹。我们得出结论，酪氨酸磷酸化以一种被ITGB1增强的方式赋予IGF-1R独特的促肿瘤信号。
