Figure 2
From: The role of the insulin-like growth factor-1 system in breast cancer
The IGF-1 receptor (auto-) regulation mechanism in breast cancer. SUMOylation of the IGF-1 receptor drives IGF-1R to nuclear translocation. Nuclear IGF-1R upregulates IGF-1R protein levels through direct binding to its own promoter. Other factors could also contribute to IGF-1R transcriptional regulation acting both as enhancers (ERα, miR515-5p and transcription factors c-Jun, Sp1, KLF6, E2F1,) or inhibitors (IGF-1, BRCA1, PARP, tumor suppressors p53, VHL, and transcription factor WT1). SUMO: small ubiquitin-like modifier; ERα: Estrogen receptor α; BRCA1: Breast cancer 1-early onset protein; KLF6: Kruppel-like factor 6; PARP: Poly-ADP ribose polymerase; VHL: von Hippel Lindau protein; WT1: Wilms tumor 1 protein.