ERK1/2-dependent activation of FCHSD2 drives cancer cell-selective regulation of clathrin-mediated endocytosis

Abstract

Clathrin-mediated endocytosis (CME) regulates the uptake of cell surface receptors, as well as their downstream signaling activities. We recently reported that signaling reciprocally regulates CME in cancer cells and that the crosstalk can contribute to cancer progression. To further explore the nature and extent of the crosstalk between signaling and CME in cancer cell biology, we analyzed a panel of oncogenic signaling kinase inhibitors for their effects on CME. Inhibition of several kinases selectively affected CME function in cancer cells. Among these, ERK1/2 inhibition selectively inhibited CME in cancer cells by decreasing the rate of CCP initiation. We identified an ERK1/2 substrate, the FCH/F-BAR and SH3 domain-containing protein, FCHSD2, as being essential for the ERK1/2-dependent effects on CME and CCP initiation. ERK1/2 phosphorylation activates FCHSD2 and regulates EGFR endocytic trafficking as well as downstream signaling activities. Loss of FCHSD2 activity in non-small-cell lung cancer cells leads to increased cell surface expression and altered signaling downstream of EGFR, resulting in enhanced cell proliferation and migration. The expression level of FCHSD2 is positively correlated with higher cancer patient survival rate, suggesting that FCHSD2 negatively affects cancer progression. These findings provide new insight into the mechanisms and consequences of the reciprocal regulation of signaling and CME in cancer cells.