AKT1, LKB1, and YAP1 Revealed as MYC Interactors with NanoLuc-Based Protein-Fragment Complementation Assay

Mol Pharmacol. 2017 Apr;91(4):339-347. doi: 10.1124/mol.116.107623. Epub 2017 Jan 13.

Abstract

The c-Myc (MYC) transcription factor is a major cancer driver and a well-validated therapeutic target. However, directly targeting MYC has been challenging. Thus, identifying proteins that interact with and regulate MYC may provide alternative strategies to inhibit its oncogenic activity. In this study, we report the development of a NanoLuc-based protein-fragment complementation assay (NanoPCA) and mapping of the MYC protein interaction hub in live mammalian cells. The NanoPCA system was configured to enable detection of protein-protein interactions (PPI) at the endogenous level, as shown with PRAS40 dimerization, and detection of weak interactions, such as PINCH1-NCK2. Importantly, NanoPCA allows the study of PPI dynamics with reversible interactions. To demonstrate its utility for large-scale PPI detection in mammalian intracellular environment, we have used NanoPCA to examine MYC interaction with 83 cancer-associated proteins in live cancer cell lines. Our new MYC PPI data confirmed known MYC-interacting proteins, such as MAX, GSK3A, and SMARCA4, and revealed a panel of novel MYC interaction partners, such as RAC-α serine/threonine-protein kinase (AKT)1, liver kinase B (LKB)1, and Yes-associated protein (YAP)1. The MYC interactions with AKT1, LKB1, and YAP1 were confirmed by coimmunoprecipitation of endogenous proteins. Importantly, AKT1, LKB1, and YAP1 were able to activate MYC in a transcriptional reporter assay. Thus, these vital growth control proteins may represent promising MYC regulators, suggesting new mechanisms that couple energetic and metabolic pathways and developmental signaling to MYC-regulated cellular programs.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Biological Assay*
  • Cell Line, Tumor
  • HEK293 Cells
  • High-Throughput Screening Assays
  • Humans
  • Luciferases / metabolism*
  • Nanoparticles / chemistry*
  • Phosphoproteins / metabolism*
  • Protein Binding
  • Protein Interaction Mapping / methods*
  • Protein-Serine-Threonine Kinases / metabolism*
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Proto-Oncogene Proteins c-myc / metabolism*
  • Reproducibility of Results

Substances

  • Phosphoproteins
  • Proto-Oncogene Proteins c-myc
  • Luciferases
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt