Abstract 2368 Uncovering MAGEB2 function using unbiased proteomics and interactome analysis

This is the authors' abstract. We don't add key points for this paper.

Melanoma antigen genes (MAGE) are a group of tumor specific genes that are normally expressed in male germline cells and aberrantly expressed in a wide range of cancers. Cancers expressing MAGEB2, a member of the MAGE family show poor patient prognosis. Expression of MAGEB2 in non-transformed cells results in increased cell proliferation. The functional basis for MAGEB2's tumorigenic, pro-proliferative effect is unclear and has been sparsely investigated. We seek to establish a mechanistic basis for MAGEB2 function and understand the biochemical role of the MAGE family of proteins. To this end we designed recombinant expression constructs of MAGEB2 with single and tandem affinity tags for generation of heterologous cell lines. We used the cells lines with robust expression of MAGEB2 to perform unbiased proteomics and generate a global protein interactome for MAGEB2. Our list of MAGE-B2 interacting proteins is highly enriched in RNA binding proteins (e.g., KHSRP, ELAV1 and AUF1) and enzymes involved in protein turnover (DCUN1D5, UBE2NL and PCMT1). First, we used a coupled invitro transcription and translation assay to enable rapid pairwise screening of interactors to ascertain validity of binding. Second, we performed co-IP experiments with candidate binding partners to triangulate domain specific binding. MAGE-B2 provides non transformed cells with a pro-proliferative advantage, and we are investigating if any of the validated interactions can recapitulate this proliferation.