title: Amyloid precursor protein modulates ERK-1 and -2 signaling.
abstract: The amyloid precursor protein (APP) is a transmembrane protein with a short cytoplasmic tail whose physiological function is unclear, although it is well documented that the proteolytic processing of APP could influence the development of Alzheimer's disease (AD) through the formation of membrane-bound C-terminal fragments (CTFs) and of beta-amyloid peptides (Abeta). We have recently shown that tyrosine-phosphorylated APP and CTFs may interact with Grb2 and ShcA adaptor proteins and that this coupling occurs at a higher extent in AD subjects only. To study the interaction between APP or CTFs and ShcA/Grb2 and to investigate their molecular target we have used as experimental model two different cell lines: H4 human neuroglioma cells and APP/APLP null mouse embryonic fibroblast cells (MEFs). Here we show that in H4 cells APP interacts with Grb2; conversely in APP/APLP-null MEF cells this interaction is possible only after the reintroduction of human APP by transfection. We have also shown that in MEF cells the transfection of a plasmid encoding for human APP wild-type enhances the phosphorylation of ERK-1 and -2 as revealed by Western blotting and immunofluorescence experiments. Finally, also in H4 cells the overexpression of APP upregulates the levels of phospho-ERK-1 and -2. In summary our data suggest that APP may influence phospho-ERK-1 and -2 signaling through its binding with Grb2 and ShcA adaptors. The meaning of this event is not clear, but APP interaction with these adaptors could be relevant to regulate mitogenic pathway.
authors: Department of Oncology, Biology and Genetics, University of Genova, Italy.
authors: Valentina
authors: V
authors: Venezia
authors: Mario
authors: M
authors: Nizzari
authors: Emanuela
authors: E
authors: Repetto
authors: Elisabetta
authors: E
authors: Violani
authors: Alessandro
authors: A
authors: Corsaro
authors: Stefano
authors: S
authors: Thellung
authors: Valentina
authors: V
authors: Villa
authors: Pia
authors: P
authors: Carlo
authors: Gennaro
authors: G
authors: Schettini
authors: Tullio
authors: T
authors: Florio
authors: Claudio
authors: C
authors: Russo
mesh_terms: D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000502:physiology*; D000818:Animals; D002460:Cell Line; D005455:Fluorescent Antibody Technique; D051379:Mice; D018613:Microscopy, Confocal; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D016564:Amyloid beta-Protein Precursor; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3