The effect of Scp160p on polyQ-mediated protein aggregation

We have previously shown that the yeast homolog of the RNA-binding vigilin proteins – Scp160p – is involved in enhancing translation efficiency in the context of codon usage. In the current study, we investigated the influence of Scp160p on the biology of polyQ reporters which differ in the codon usage of their polyQ regions. We observe that Scp160p facilitates aggregation of the polyQ reporters independent of codon usage. To explore if Scp160p might also facilitate the aggregation of endogenous polyQ-containing proteins in the yeast proteome, we combined filter trap binding and dimethyl labeling mass spectrometry to assess the aggregation state of the proteome in scp160Δ cells. Filter trap binding allows the isolation of protein aggregates which are SDS-resistant (a feature of polyQ aggregates) from wild-type and scp160Δ cells. Dimethyl labeling with nanoLC-MS/MS provided a quantitative comparison of the amount of aggregated proteins isolated by filter trap binding.