Non-redundant role of Shc in Erk activation by cytoskeletal reorganization.
We have shown previously that cytoskeletal reorganization (CSR) induced by pharmacological reagents such as colchicine or cytochalasins can up-regulate the urokinase-type plasminogen activator (uPA) gene via the Ras/Erk signaling pathway. In this present study using the small interfering RNA technique, we have found that ShcA adapter proteins play a rather active role in CSR-induced Erk activation, contrary to their mostly redundant role in other signaling pathways, e.g. growth factor-induced Erk activation, where Grb2 can bind directly to the receptor tyrosine kinase and activate Erk in the absence of ShcA. ShcA knockdown abolished CSR-induced activation of both Erk and the uPA promoter. Expression of small interfering RNA-escaping silent mutants of p52 or p46 but not p66 ShcA isoform efficiently rescued CSR-induced Erk activation. Moreover, we have shown that phosphorylation of either Tyr-239/Tyr-240 or Tyr-313 in p52(ShcA) can mediate CSR-induced Erk activation equally well. In a quest for molecules upstream of ShcA in this signaling, we found that CSR-induced ShcA tyrosine phosphorylation, its association with Grb2, Erk activation, and uPA gene expression were all dependent on Rho kinase, p38 mitogen-activated protein kinase, and Src. In summary, we have found a novel, non-redundant role for ShcA in contrast to its redundant role in many other signaling pathways.
Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.
Amir
A
Faisal
Sandra
S
Kleiner
Yoshikuni
Y
Nagamine
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D015153:Blotting, Western; D003078:Colchicine / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D017930:Genes, Reporter; D018374:LLC-PK1 Cells; D051379:Mice; D008856:Microscopy, Fluorescence; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation; D018384:Oxidative Stress; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins; D015398:Signal Transduction; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D013552:Swine; D014162:Transfection; D014443:Tyrosine / Q000737:chemistry; D015854:Up-Regulation; D014568:Urokinase-Type Plasminogen Activator / Q000096:biosynthesis; D048051:p38 Mitogen-Activated Protein Kinases
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D020033:Protein Isoforms; D011506:Proteins; D034741:RNA, Small Interfering; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D014568:Urokinase-Type Plasminogen Activator; D003078:Colchicine