OncoPPi-informed discovery of mitogen-activated protein kinase kinase 3 as a novel binding partner of c-Myc

Protein arbor network map of MAP Kinase-3 and Myc

Image attributed to the CTD2 Dashboard Gene Cart tool.

Ivanov AA, Gonzalez-Pecchi V, Khuri LF, Niu Q, Wang Y, Xu Y, Bai Y, Mo X, Prochownik EV, Johns MA, Du Y, Khuri FR, Fu H.

Oncogene

June 19, 2017

Mitogen-activated protein kinase kinase 3 (MKK3) is a dual threonine/tyrosine protein kinase that regulates inflammation, proliferation and apoptosis through specific phosphorylation and activation of the p38 mitogen-activated protein kinase. However, the role of MKK3 beyond p38-signaling remains elusive. Recently, we reported a protein-protein interaction (PPI) network of cancer-associated genes, termed OncoPPi, as a resource for the scientific community to generate new biological models. Analysis of the OncoPPi connectivity identified MKK3 as one of the major hub proteins in the network. Here, we show that MKK3 interacts with a large number of proteins critical for cell growth and metabolism, including the major oncogenic driver MYC. Multiple complementary approaches were used to demonstrate the direct interaction of MKK3 with MYC in vitro and in vivo. Computational modeling and experimental studies mapped the interaction interface to the MYC helix-loop-helix domain and a novel 15-residue MYC-binding motif in MKK3 (MBM). The MBM in MKK3 is distinct from the known binding sites for p38 or upstream kinases. Functionally, MKK3 stabilized MYC protein, enhanced its transcriptional activity and increased expression of MYC-regulated genes. The defined MBM peptide mimicked the MKK3 effect in promoting MYC activity. Together, the exploration of OncoPPi led to a new biological model in which MKK3 operates by two distinct mechanisms in cellular regulation through its phosphorylation of p38 and its activation of MYC through PPI.

Type of Publication: 
Collaboration
Primary
Program:
CTD²
Last updated: July 12, 2017