title: The interaction between the adaptor protein APS and Enigma is involved in actin organisation.
abstract: APS (adaptor protein with PH and SH2 domains) is an adaptor protein phosphorylated by several tyrosine kinase receptors including the insulin receptor. To identify novel binding partners of APS, we performed yeast two-hybrid screening. We identified Enigma, a PDZ and LIM domain-containing protein that was previously shown to be associated with the actin cytoskeleton. In HEK 293 cells, Enigma interacted specifically with APS, but not with the APS-related protein SH2-B. This interaction required the NPTY motif of APS and the LIM domains of Enigma. In NIH-3T3 cells that express the insulin receptor, Enigma and APS were partially co-localised with F-actin in small ruffling structures. Insulin increased the complex formation between APS and Enigma and their co-localisation in large F-actin containing ruffles. While in NIH-3T3 and HeLa cells the co-expression of both Enigma and APS did not modify the actin cytoskeleton organisation, expression of Enigma alone led to the formation of F-actin clusters. Similar alteration in actin cytoskeleton organisation was observed in cells expressing both Enigma and APS with a mutation in the NPTY motif. These results identify Enigma as a novel APS-binding protein and suggest that the APS/Enigma complex plays a critical role in actin cytoskeleton organisation.
authors.affiliation: INSERM U568 and IFR 50, Faculté de Médecine, Avenue de Valombrose, 06107 Nice Cedex 02, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Barrès
authors.forename: Teresa
authors.initials: T
authors.lastname: Gonzalez
authors.forename: Yannick
authors.initials: Y
authors.lastname: Le Marchand-Brustel
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Tanti
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D000199:Actins / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D020816:Amino Acid Motifs / Q000502:physiology; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D022081:Cell Surface Extensions / Q000378:metabolism; D003598:Cytoskeletal Proteins; D003599:Cytoskeleton / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D060588:LIM Domain Proteins; D051379:Mice; D041681:NIH 3T3 Cells; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D011972:Receptor, Insulin / Q000378:metabolism
chemical_list: D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D003598:Cytoskeletal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins; C484381:Pdlim7 protein, mouse; C488161:Sh2b2 protein, mouse; D011972:Receptor, Insulin