The ShcD phosphotyrosine adaptor subverts canonical EGF receptor trafficking

Abstract

Shc family signalling adaptors connect activated transmembrane receptors to proximal effectors, and most also contain a sequence involved in clathrin-mediated receptor endocytosis. Notably, this AP2 adaptin-binding motif (AD) is absent from the ShcD (also known as Shc4) homolog, which also uniquely promotes ligand-independent phosphorylation of the epidermal growth factor receptor (EGFR). We now report that cultured cells expressing ShcD exhibit reduced EGF uptake, commensurate with a decrease in EGFR surface presentation. Under basal conditions, ShcD colocalises with the EGFR and facilitates its phosphorylation, ubiquitylation and accumulation in juxtanuclear vesicles identified as Rab11-positive endocytic recycling compartments. Accordingly, ShcD also functions as a constitutive binding partner for the E3 ubiquitin ligase Cbl. EGFR phosphorylation and focal accumulation likewise occur upon ShcD co-expression in U87 glioma cells. Loss of ShcD phosphotyrosine-binding function or insertion of the ShcA AD sequence each restore ligand acquisition through distinct mechanisms. The AD region also contains a nuclear export signal, indicating its multifunctionality. Overall, ShcD appears to possess several molecular permutations that actively govern the EGFR, which may have implications in development and disease.

Src homology 2 domains enhance tyrosine phosphorylation in vivo by protecting binding sites in their target proteins from dephosphorylation

“…For example, recently published work has shown that SHCD overexpression results in a significant increase in phosphorylation of EGFR in a PTB-dependent manner. The largest increases occurred at the SHCD PTB-binding site, pTyr-1148, and to a lesser extent at pTyr-1068 and pTyr-1173 (37). These data are highly consistent with phosphosite protection, although this was not considered as a potential mechanism.…”

“…GRB2 mediates signaling through a complex series of downstream pathways that could indirectly enhance EGFR phosphorylation, for example by increasing cytoplasmic kinase activity or suppressing phosphatase activity (35)(36)(37). To rule out downstream signaling as a driver of GRB2-mediated EGFR phosphoenhancement, we compared protein tyrosine phosphorylation after expression of full-length WT GRB2 and four GRB2-derived constructs as follows: a fluorescently tagged GRB2 SH2 domain (tdEOS-GRB2 SH2), previously shown to be recruited to the plasma membrane of EGF-stimulated cells (34,38); fulllength GRB2 and tdEOS-GRB2 SH2 constructs containing a mutation in the SH2 domain (R86K) previously shown to abrogate phospho-dependent interaction (39,40); and a chimeric protein in which the SH2 domain of GRB2 is replaced by that from CRK, referred to here as GCG ( Fig.…”

miR-26a regulates extracellular vesicle secretion from prostate cancer cells via targeting SHC4, PFDN4 and CHORDC1

“…SHC4 is one of the proteins of the Src homology and collagen family, ShcA, ShcB, ShcC and SHC4 (or ShcD), in chronological order of their discovery. Shc proteins are known to engage in the EGFR internalization process 25 , and ShcD was reported to alter steady-state EGFR trafficking dynamics, which reduces cellular ligand sensitivity by recruiting the EGFR into juxtanuclear vesicles identified as Rab-11-positive endocytic recycling compartments 26 .…”

The role of the ShcD and RET interaction in neuroblastoma survival and migration

“…GDNF treatment was previously shown to provoke RET internalization [23] , which indeed supports the endosomal colocalization of ShcD and RET in GDNF-treated cells. Ina addition, a recent report by Will and et al showed that ShcD colocalizes with EGFR at the perinuclear endosomal compartment [24] .…”