EGF Receptor Signaling Stimulates SRC Kinase Phosphorylation of Clathrin, Influencing Clathrin Redistribution and EGF Uptake

Abstract

Epidermal growth factor (EGF) binding to its receptor causes rapid phosphorylation of the clathrin heavy chain at tyrosine 1477, which lies in a domain controlling clathrin assembly. EGF-mediated clathrin phosphorylation is followed by clathrin redistribution to the cell periphery and is the product of downstream activation of SRC kinase by EGF receptor (EGFR) signaling. In cells lacking SRC kinase, or cells treated with a specific SRC family kinase inhibitor, EGF stimulation of clathrin phosphorylation and redistribution does not occur, and EGF endocytosis is delayed. These observations demonstrate a role for SRC kinase in modification and recruitment of clathrin during ligand-induced EGFR endocytosis and thereby define a novel effector mechanism for regulation of endocytosis by receptor signaling.

Adaptor protein Shc undergoes translocation and mediates up‐regulation of the tyrosine kinase c‐Src in EGF‐stimulated A431 cells

“…4B,C). It is known that activated EGFR undergoes endocytosis involving dynamin-regulated and clathrincoated endosomes (Vieira et al 1996;Carter & Sorkin 1998;Wilde et al 1999). Thus, we conclude that the cytoplasmic vesicle structures containing both GFP-P52 and EGFR are endosomes.…”

Large‐scale proteomic analysis of tyrosine‐phosphorylation induced by T‐cell receptor or B‐cell receptor activation reveals new signaling pathways

“…The clathrin-dependent pathway has been shown to be the primary pathway for ligand-induced BCR endocytosis, and raft structures appear to be required for efficient phosphorylation of clathrin heavy chain [21,33]. Tyrosine-phosphorylation of clathrin heavy chain is induced by an SRC-type protein kinase in response to stimulation of various receptor types, and the level of phosphorylation correlates with the rate of receptor internalization [21,[34][35][36][37]. Our data support a requirement for phosphorylation of clathrin heavy chain as well as for that of other endocytosis-related factors in BCR internalization.…”

Receptor tyrosine kinases positively regulate BACE activity and Amyloid-β production through enhancing BACE internalization

“…It is known that c-Src mediates internalization of membrane proteins by phosphorylating the internalized protein or components of the internalization machinery [20][21][22]24]. Our results suggest that in this case c-Src may phosphorylate components of the internalization machinery because no tyrosine residue was found in the cytosolic tail of BACE [16,21,23,24,62,63]. Although the precise mechanism of enhanced BACE internalization mediated by c-Src still remains unclear, the results from this study indicate that c-Src may serve as a potential therapeutic target for AD.…”

“…Upon activation, RTKs undergo phosporylation at specific tyrosine sites and then bind with SH2 (Src homology region) or PTB (phosphotyrosine binding) domain-containing proteins to activate downstream effectors such as c-Src, MAPK, and PKC [19]. Particularly, c-Src has been demonstrated to regulate the internalization of membrane proteins via different mechanisms [20][21][22][23][24], implicating a means for RTK-mediated regulation of other membrane proteins. RTK internalization is required for their normal signaling.…”