title: Similar requirement for clathrin in EGF- and HGF- stimulated Akt phosphorylation.
abstract: Receptor tyrosine kinases, such as the epidermal growth factor (EGF) receptor (EGFR) and Met lead to activation of intracellular signals including Akt, a critical regulator of cell survival, metabolism and proliferation. Upon binding their respective ligands, each of these receptors is recruited into clathrin coated pits (CCPs) eventually leading to endocytosis. We have recently shown that phosphorylation of Gab1 and Akt following EGFR activation requires clathrin, but does not require receptor endocytosis. We examined whether clathrin regulates Akt signaling downstream of Met, as it does for EGFR signaling. Stimulation with the Met ligand Hepatocyte Growth Factor (HGF) leads to enrichment of phosphorylated Gab1 (pGab1) within CCPs in ARPE-19 cells. Perturbation of clathrin using the inhibitor pitstop2 decreases HGF-stimulated Akt phosphorylation. These results indicate that clathrin may regulate Met signaling leading to Akt phosphorylation similarly as it does for EGFR signaling.
authors.affiliation: Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada; Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, Canada.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Lucarelli
authors.affiliation: Department of Chemistry and Biology, Ryerson University , Toronto, Ontario, Canada.
authors.forename: Rohan
authors.initials: R
authors.lastname: Pandey
authors.affiliation: Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada; Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, Canada.
authors.forename: Gurjeet
authors.initials: G
authors.lastname: Judge
authors.affiliation: Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada; Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, Canada; Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Costin N
authors.initials: CN
authors.lastname: Antonescu
keywords: TIRF microscopy; clathrin; endocytosis; membrane traffic; phosphorylation; receptor tyrosine kinase; signaling adaptor; signaling microdomain; signaling scaffold