The CHORD protein CHP-1 regulates EGF receptor trafficking and signaling in <i>C. elegans</i> and in human cells.

Haag, Andrea; Walser, Michael; Henggeler, Adrian; Hajnal, Alex · Elife · 2020

basic_science · Level V

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Abstract

The intracellular trafficking of growth factor receptors determines the activity of their downstream signaling pathways. Here, we show that the putative HSP-90 co-chaperone CHP-1 acts as a regulator of EGFR trafficking in <i>C. elegans</i>. Loss of <i>chp-1</i> causes the retention of the EGFR in the ER and decreases MAPK signaling. CHP-1 is specifically required for EGFR trafficking, as the localization of other transmembrane receptors is unaltered in <i>chp-1(lf)</i> mutants, and the inhibition of <i>hsp-90</i> or other co-chaperones does not affect EGFR localization. The role of the CHP-1 homolog CHORDC1 during EGFR trafficking is conserved in human cells. Analogous to <i>C. elegans</i>, the response of CHORDC1-deficient A431 cells to EGF stimulation is attenuated, the EGFR accumulates in the ER and ERK2 activity decreases. Although CHP-1 has been proposed to act as a co-chaperone for HSP90, our data indicate that CHP-1 plays an HSP90-independent function in controlling EGFR trafficking through the ER.

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