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

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 C. elegans. Loss of chp-1 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 chp-1(lf) mutants, and the inhibition of hsp-90 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 C. elegans, 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.

Nutritional vitamin B12 regulates RAS/MAPK-mediated cell fate decisions through the one-carbon metabolism

“…We next used A431 epidermoid carcinoma cells, which overexpress EGFR and strongly respond to EGF stimulation by forming filopodia in a MAPK-dependent manner (Haag et al, 2020; Van de Vijver et al, 1991). Since filopodia formation is difficult to assess quantitatively, we categorized cellular morphologies into three classes; 0 for cells without filopodia, 1 for cells with small filopodia covering part of the cortex, and 2 for cells with long filopodia covering most of the cortex ( Figure S8A ).…”

“…Cells were seeded at 80’000 cells/ml density in DMEM medium with or without supplements. After 32 hours, cells were exposed to thymidine (1:50) to arrest the cell cycle as described in Haag et al, 2020 (first thymidine block). 16 hours after, the first thymidine block was released by replacing the medium.…”

“…We first performed collective cell migration assays with A549 lung cancer cells that carry a KRAS G12S mutation, to test if methionine restriction (MR) interfered with cell migration. To exclude possible effects of reduced cell proliferation, we performed these assays with cells arrested in the G1 phase by double thymidine blockade (Haag et al, 2020). A549 cells grown in MR (without methionine but supplemented with its precursor homocysteine) migrated at a lower speed than cells without MR (Figures 7A, 7A We next used A431 epidermoid carcinoma cells, which overexpress EGFR and strongly respond to EGF stimulation by forming filopodia in a MAPK-dependent manner (Haag et al, 2020;Van de Vijver et al, 1991).…”

Oncolytic Virus Affects the RAS Pathway in Cancer: RNA Sequence Analysis

“…The downregulation of CHORDC1 has been shown to promote the interaction between ROCKII and NPM to result in an increase in ROCKII kinase activity, which leads to centrosome amplification [14]. CHORDC1 also ensures the localization of the tyrosine kinase receptor EGFR to the plasma membrane, which in turn regulates EGFR activity and EGF-induced actin cytoskeleton remodeling [15]. Additionally, there exists a novel ADP-dependent HSP90 interaction with the CHORDC1 [16].…”

Extracellular HSP90 Machineries Build Tumor Microenvironment and Boost Cancer Progression

“…Inside the cells, Morgana regulates signal transduction by binding and inhibiting Rho kinases I and II ( Ferretti et al, 2010 ; Fusella et al, 2014 ) and promotes NF-kB activation ( Fusella et al, 2017 ). It is also involved in microtubule polymerization ( Palumbo et al, 2020 ), EGF receptor trafficking ( Haag et al, 2020 ), and extracellular vesicle secretion ( Urabe et al, 2020 ). We recently found that Morgana is secreted by several cancer cells through an unconventional pathway and it associates with HSP90 in the extracellular milieu.…”