受体酪氨酸激酶（RTK）过度表达与多种癌症的发生和进展有关。传统上认为 RTK 通过配体诱导的酪氨酸磷酸化启动细胞质信号传导途径，但最近的证据表明第二层信号传导取决于非激活 RTK 的富含脯氨酸基序 (PRM) 区域介导的相互作用。超过 40% 的 RTK 的 C 端存在 PRM，以及人类基因组编码的 PRM 结合蛋白的丰度表明，可能存在大量先前未探索的相互作用，这些相互作用增加了 RTK 细胞内相互作用组。在这里，我们使用亲和纯化质谱和计算机富集分析探索 RTK PRM 相互作用组及其潜在意义。包含含有 EGFR、FGFR2 和 HER2 的 C 末端尾区的 PRM 的肽被用作诱饵，以亲和纯化来自不同癌细胞系裂解物的结合蛋白。鉴定出 490 个独特的相互作用因子，其中具有代谢、稳态和迁移功能的蛋白质比例过高。这表明来自 RTK 的 PRM 可能维持癌细胞中多样化的相互作用组。由于 RTK 过度表达在癌症中很常见，因此 RTK PRM 衍生的信号传导可能是导致负面癌症结果（包括对激酶抑制剂耐药性）的一个重要但尚未充分探索的因素。© 2024 作者。

Receptor tyrosine kinase (RTK) overexpression is linked to the development and progression of multiple cancers. RTKs are classically considered to initiate cytoplasmic signalling pathways via ligand-induced tyrosine phosphorylation, however recent evidence points to a second tier of signalling contingent on interactions mediated by the proline-rich motif (PRM) regions of non-activated RTKs. The presence of PRMs on the C-termini of >40 % of all RTKs and the abundance of PRM-binding proteins encoded by the human genome suggests that there is likely to be a large number of previously unexplored interactions which add to the RTK intracellular interactome. Here, we explore the RTK PRM interactome and its potential significance using affinity purification mass spectrometry and in silico enrichment analyses. Peptides comprising PRM-containing C-terminal tail regions of EGFR, FGFR2 and HER2 were used as bait to affinity purify bound proteins from different cancer cell line lysates. 490 unique interactors were identified, amongst which proteins with metabolic, homeostatic and migratory functions were overrepresented. This suggests that PRMs from RTKs may sustain a diverse interactome in cancer cells. Since RTK overexpression is common in cancer, RTK PRM-derived signalling may be an important, but as yet underexplored, contributor to negative cancer outcomes including resistance to kinase inhibitors.© 2024 The Authors.