Opposing roles of ZEB1 in the cytoplasm and nucleus control cytoskeletal assembly and YAP1 activity

Epithelial-mesenchymal transition (EMT) facilitates cancer invasion and is initiated by mesenchyme-driving transcription factors and actin cytoskeletal assembly. We show a cytoplasmic-to-nuclear transport gradient of the EMT transcription factor Zeb1 toward sites of invasion in lung adenocarcinoma (LUAD), driven by the EMT inducer Tgfb, which is expressed in M2 polarized macrophages. We show that Zeb1 binds free actin monomers and RhoA in the cytoplasm to inhibit actin polymerization, blocking cell migration and Yap1 nu-clear transport. Tgfb causes turnover of the scaffold protein Rassf1a, which targets RhoA. Release of this RhoA inhibition in response to Tgfb overcomes Zeb1's block of cytoskeleton assembly and frees it for nuclear transport. A ZEB1 nuclear transport signature highlights EMT progression, identifies dedifferentiated inva-sive/metastatic human LUADs, and predicts survival. Blocking Zeb1 nuclear transport with a small molecule identified in this study inhibits cytoskeleton assembly, cell migration, Yap1 nuclear transport, EMT, and pre -cancerous-to-malignant transition.

Automated summary

This study shows a cytoplasmic-to-nuclear transport gradient of the EMT transcription factor Zeb1 in cancer cells, which is regulated by the EMT inducer Tgfb. The transport of Zeb1 promotes the assembly of the actin cytoskeleton and cell migration. Inhibition of Zeb1 nuclear transport can suppress the malignant transition of cancer cells.