The Drosophila Epidermal Growth Factor Receptor does not act in the nucleus

Abstract

Mammalian members of the ErbB family, including the epidermal growth factor receptor (EGFR), can regulate transcription, DNA replication and repair through nuclear entry of either the full-length proteins or their cleaved cytoplasmic domains. In cancer cells, these nuclear functions contribute to tumor progression and drug resistance. Here, we examined whether the single EGFR can also localize to the nucleus. A chimeric EGFR protein fused at its cytoplasmic C-terminus to DNA-binding and transcriptional activation domains strongly activated transcriptional reporters when overexpressed in cultured cells or However, this activity was independent of cleavage and endocytosis. Without an exogenous activation domain, EGFR fused to a DNA-binding domain did not activate or repress transcription. Addition of the same DNA-binding and transcriptional activation domains to the endogenous locus through genome editing led to no detectable reporter expression in wild-type or oncogenic contexts. These results show that, when expressed at physiological levels, the cytoplasmic domain of the EGFR does not have access to the nucleus. Therefore, nuclear EGFR functions are likely to have evolved after vertebrates and invertebrates diverged.

Quantitative analyses of EGFR localization and trafficking dynamics in the follicular epithelium

“…In the eye disc, a high level of EGFR was detected in the morphogenetic furrow (Fig. 2C), which is consistent with the endogenous pattern (Courgeon et al, 2018;Zak and Shilo, 1992). In the haltere, a high level of EGFR was found in the region surrounding the dorsal-ventral compartment boundary, which is consistent with the pattern of Egfr (Pallavi et al, 2006) (Fig.…”

“…The same approach was used to label Dorsal in the Drosophila embryo and EGFR with Emerald-GFP in mice (Carrell et al, 2017;Haag et al, 2014;Yang et al, 2017). The tagged EGFR fly recapitulated the endogenous pattern of the receptor in the FCs (Sapir et al, 1998), embryo (Konikoff et al, 2012), and imaginal discs of the third instar larvae (Courgeon et al, 2018;Guichard et al, 1999;Pallavi et al, 2006;Zak and Shilo, 1992). Hence, this fly can be used as a tool to characterize cellular localization and carry out quantitative experiments with the EGFR, which thus far have been lacking in tissues (Patel and Shvartsman, 2018).…”

The NAE Pathway: Autobahn to the Nucleus for Cell Surface Receptors

“…One can also wonder at the evolutionary origin of this nuclear targeting pathway. A recent study has proposed that drosophila EGFR may not act in the nucleus and therefore the nuclear functions of RTKs might have emerged relatively late in metazoan history [133]. However, nuclear translocation constitutes a relatively simple signaling cascade: the receptor interacts directly with its promoter targets.…”