ShcA regulates neurite outgrowth stimulated by neural cell adhesion molecule but not by fibroblast growth factor 2: evidence for a distinct fibroblast growth factor receptor response to neural cell adhesion molecule activation.
Homophilic binding in trans of the neural cell adhesion molecule (NCAM) mediates adhesion between cells and leads, via activation of intracellular signaling cascades, to neurite outgrowth in primary neurons as well as in the neuronal cell line PC12. NCAM mediates neurite extension in PC12 cells by two principal routes of signaling: NCAM/Fyn and NCAM/fibroblast growth factor receptor (FGFR), respectively. Previous studies have shown that activation of mitogen-activated protein kinases is a pivotal point of convergence in NCAM signaling, but the mechanisms behind this activation are not clear. Here, we investigated the involvement of adaptor proteins in NCAM and fibroblast growth factor 2 (FGF2)-mediated neurite outgrowth in the PC12-E2 cell line. We found that both FGFR substrate-2 and Grb2 play important roles in NCAM as well as in FGF2-stimulated events. In contrast, the docking protein ShcA was pivotal to neurite outgrowth induced by NCAM, but not by FGF2, in PC12 cells. Moreover, in rat cerebellar granule neurons, phosphorylation of ShcA was stimulated by an NCAM mimicking peptide, but not by FGF2. This activation was blocked by inhibitors of both FGFR and Fyn, indicating that NCAM activates FGFR signaling in a manner distinct from FGF2 stimulation, and regulates ShcA phosphorylation by the concerted efforts of the NCAM/FGFR as well as the NCAM/Fyn signaling pathway.
Protein Laboratory, Institute of Molecular Pathology, University of Copenhagen, Blegdamsvej 3, DK-2200, Denmark.
Anders M
AM
Hinsby
Line
L
Lundfald
Dorte K
DK
Ditlevsen
Irina
I
Korshunova
Lone
L
Juhl
Susan O
SO
Meakin
Vladimir
V
Berezin
Elisabeth
E
Bock
D048868:Adaptor Proteins, Signal Transducing / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D018920:Coculture Techniques; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D051380:GRB2 Adaptor Protein; D006801:Humans; D008565:Membrane Proteins / Q000502:physiology; D051379:Mice; D019006:Neural Cell Adhesion Molecules / Q000494:pharmacology*; D016501:Neurites / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D016716:PC12 Cells; D010750:Phosphoproteins / Q000502:physiology; D010766:Phosphorylation / Q000187:drug effects; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051076:Proto-Oncogene Proteins c-fyn; D051381:Rats; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism*; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D019061:src-Family Kinases / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; C106534:FRS2 protein, human; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; C495949:Grb2 protein, mouse; C495950:Grb2 protein, rat; D008565:Membrane Proteins; D019006:Neural Cell Adhesion Molecules; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D017468:Receptors, Fibroblast Growth Factor; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; C528035:Shc1 protein, rat; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D016222:Fibroblast Growth Factor 2; C494957:FYN protein, human; C494960:Fyn protein, mouse; C494961:Fyn protein, rat; D051076:Proto-Oncogene Proteins c-fyn; D019061:src-Family Kinases