RESUMO
Cancer cell survival is highly dependent on its metabolic reprogramming, which supports not only cell growth but also confers to the tumor cells characteristics to initiate migration and colonization. Among the different mechanisms that are involved, translational control plays a significant role in oncogenesis; however, its impact on cancer progression still remains poorly understood. A study by Navickas and colleagues revealed that the RNA-binding protein heterogeneous nuclear ribonucleoprotein C (HNRNPC) functions as a translational regulator, and its downregulation in highly metastatic cells leads to the lengthening of 3' untranslated regions in HNRNPC-bound mRNAs, resulting in translational repression mediated by the AGO-miRNA RNA-induced silencing complex.
RESUMO
Understanding the function of the thousands of cellular proteins is a central question in molecular cell biology. As proteins are typically part of multiple dynamic and often overlapping macromolecular complexes exerting distinct functions, the identification of protein-protein interactions (PPI) and their assignment to specific complexes is a crucial but challenging task. We present a protein fragments complementation assay integrated with the proximity-dependent biotinylation technique BioID. Activated on the interaction of two proteins, split-BioID is a conditional proteomics approach that allows in a single and simple assay to both experimentally validate binary PPI and to unbiasedly identify additional interacting factors. Applying our method to the miRNA-mediated silencing pathway, we can probe the proteomes of two distinct functional complexes containing the Ago2 protein and uncover the protein GIGYF2 as a regulator of miRNA-mediated translation repression. Hence, we provide a novel tool to study dynamic spatiotemporally defined protein complexes in their native cellular environment.
