Quantitative analysis of the TNF-?-induced phosphoproteome reveals AEG-1/MTDH/LYRIC as an IKK? substrate.

ABSTRACT: The inhibitor of the nuclear factor-?B (I?B) kinase (IKK) complex is a key regulator of the canonical NF-?B signalling cascade and is crucial for fundamental cellular functions, including stress and immune responses. The majority of IKK complex functions are attributed to NF-?B activation; however, there is increasing evidence for NF-?B pathway-independent signalling. Here we combine quantitative mass spectrometry with random forest bioinformatics to dissect the TNF-?-IKK?-induced phosphoproteome in MCF-7 breast cancer cells. In total, we identify over 20,000 phosphorylation sites, of which ?1% are regulated up on TNF-? stimulation. We identify various potential novel IKK? substrates including kinases and regulators of cellular trafficking. Moreover, we show that one of the candidates, AEG-1/MTDH/LYRIC, is directly phosphorylated by IKK? on serine 298. We provide evidence that IKK?-mediated AEG-1 phosphorylation is essential for I?B? degradation as well as NF-?B-dependent gene expression and cell proliferation, which correlate with cancer patient survival in vivo.

SUBMITTER: Krishnan RK 

PROVIDER: S-EPMC4396366 | biostudies-literature | 2015 Apr

REPOSITORIES: biostudies-literature