title: Functional molecular imaging of ILK-mediated Akt/PKB signaling cascades and the associated role of beta-parvin.
abstract: Visualization and quantification of the dynamics of protein-protein interactions in living cells can be used to explore the macromolecular events involved in signal transduction processes. In this study, functional molecular imaging using a luciferase-based complementation method demonstrated how the integrin-linked kinase (ILK)-mediated protein complex controls downstream signals. The luciferase complementation assay showed that Akt1 preferentially binds to beta-parvin rather than to ILK within the complex. Moreover, photon flux from the interaction between beta-parvin and Akt1 increased following serum stimulation, and the beta-parvin-Akt1 interaction was dependent on phosphoinositide 3-kinase. Intriguingly, small interfering (si)RNA-mediated beta-parvin knockdown increased photon flux from the interaction between ILK and Akt1, leading to stabilization of hypoxia-inducible factor-1alpha and increased expression of vascular endothelial growth factor-A. These data from functional molecular imaging demonstrated that beta-parvin plays a regulatory role in the ILK-mediated Akt (also called protein kinase B) signaling cascades, suggesting that beta-parvin might be a crucial modulator of cell survival.
authors.affiliation: Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan. mkimura@jichi.ac.jp
authors.forename: Mariko
authors.initials: M
authors.lastname: Kimura
authors.forename: Takashi
authors.initials: T
authors.lastname: Murakami
authors.forename: Shinae
authors.initials: S
authors.lastname: Kizaka-Kondoh
authors.forename: Masayuki
authors.initials: M
authors.lastname: Itoh
authors.forename: Keiji
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Hojo
authors.forename: Makoto
authors.initials: M
authors.lastname: Takano
authors.forename: Kazuomi
authors.initials: K
authors.lastname: Kario
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Shimada
authors.forename: Eiji
authors.initials: E
authors.lastname: Kobayashi
mesh_terms: D000185:Actinin / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D006801:Humans; D051793:Hypoxia-Inducible Factor 1 / Q000378:metabolism; D047468:Immunoprecipitation; D051379:Mice; D041681:NIH 3T3 Cells; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D000099200:Scaffold Protein ILK
chemical_list: D000185:Actinin; D051793:Hypoxia-Inducible Factor 1; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D042461:Vascular Endothelial Growth Factor A; D000099200:Scaffold Protein ILK; C486591:PARVB protein, human; C500559:Parvb protein, mouse