Ege, Liege, Belgium; 3Developmental Neurobiology Unit, GIGA-Neurosciences, GIGA-R, University of Liege, Liege, Belgium; 4Walloon ` Excellence in Life Sciences and Biotechnology (WELBIO), Wallonia, Belgium; 5Animal Facility, University of Liege, CHU, IL-1 Antagonist Biological Activity Sart-Tilman, Liege 4000, Belgium; six Mechanisms of Cancer, Friedrich Miescher Institute for Biomedical Investigation (FMI), Basel, Switzerland; 7Center for Human Genetics, KU Leuven, Leuven, IL-6 Antagonist MedChemExpress Belgium and 8 Center for the biology of illness, VIB, KU Leuven, Leuven, Belgium ` ` Corresponding author: A Chariot, Laboratory of Clinical Chemistry, GIGA-R, Tour GIGA, ?two B34, Sart-Tilman, University of Liege, CHU, Sart-Tilman, Liege 4000, Belgium. Tel: +32 four 366 2472; Fax: +32 4 366 4534; E-mail: [email protected] 9 These authors contributed equally to this work. Keyword phrases: TBK1; AKT; HPIP; MDM2; estrogens Abbreviations: CAS, Cellular apoptosis susceptibility; EGF, Epithelial growth element; ERa, Estrogen receptor alpha; GREB1, Development regulation by estrogen in breast cancer 1; FOXO3a, Forkhead box O3; HPIP, Microtubule-binding protein hematopoietic PBX-interaction protein; HUWE1, HECT, UBA and WWE domain-containing protein 1; IKK, I kappaB alpha kinase; MDM2, Mouse double minute 2; MEC, Mammary epithelial cell; NAP1, NAK (NF-kappaB-activating kinase)-associated protein 1; NEMO, NF-kappa B critical modulator; PBX1, Pre-B-cell leukemia homeobox protein 1; PCR, Polymerase chain reaction; PI3K, Phosphatidylinositide 3-kinase; TANK, TRAF household member related NF-kappaB activator; TBK1, TANK-binding kinase 1; TNFa, Tumor necrosis issue alphaReceived 14.six.13; revised 18.12.13; accepted 23.12.13; Edited by K Vousden; published on-line 31.1.MDM2 restrains estrogen-mediated AKT activation K Shostak et alits p53-dependent transcription and by preventing its degradation. Because of this, AKT activity is sustained in mammary epithelial cells. Pharmacological inhibition of MDM2 also increases p53-dependent HPIP transcription and prevents HPIP protein degradation by turning off TBK1 activity in breast cancer cells. Therefore, our information indicate that p53 reactivation by means of MDM2 inhibition may result in undesired activation of AKT signaling through HPIP upregulation.Results HPIP is actually a TBK1-interacting protein. AKT signaling contributes to resistance to targeted therapies in breast cancer.23 Given the capacity of IKK-related kinases TBK1 and IKKe to directly phosphorylate AKT,24?six we aimed to identify new TBK1 substrates by way of interactomic studies to improved comprehend the molecular hyperlink among TBK1 and AKT. We conducted a yeast two-hybrid screen utilizing the C-terminal domain of TBK1 (amino acids 529?29) fused towards the DNA-binding domain in the GAL4 transcription element as bait (Figure 1a). Amongst 47 TBK1-interacting clones, four encoded TANK, which was previously reported as a TBK1associated protein.27 Two clones encoded a product lacking the very first 205 amino acids of HPIP, whereas a third clone encoded the C-terminal a part of HPIP (amino acids 275?31) (Figure 1a). Co-immunoprecipitation (IP) experiments confirmed the interaction involving exogenously expressed epitope-tagged TBK1 and HPIP in HEK293 cells (Figure 1b; Supplementary Figures S1A and S1B, see our Supplementary Information Section). In agreement using the yeast two-hybrid data, the C-terminal domain of TBK1 was necessary for the binding to HPIP, as the TBK1DC30 mutant failed to co-precipitate TBK1 (Figure 1b). Interestingly, the kinase-dead version of TBK1 (TBK1 KD) strongly.
