Oral Sessions
（Day1, Day2, Day3, Day4）
Poster Presentations
（Day1, Day2, Day3, Day4）
Luncheon Seminars
（Day1, Day2, Day3, Day4）
Oral Sessions
- Day 4, May 18（Fri.） 14:25-14:45 Room B (Seiun 1)
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4B-O2-P-1425（2P-62） PDF
Ribosomics reveals a novel mechanism for translational regulation
The ribosome is a large ribonucleoprotein complex which translates mRNAs into proteins and thus plays a central role in all living cells. Emerging evidence indicates that heterogeneity in ribosome composition can give rise to specialized functions [1]. Until now, research mainly focused on differences in core ribosomal proteins and associated factors. The impact of posttranslational modifications has not yet been studied systematically. Analyzing ribosome heterogeneity is challenging since individual proteins can be part of different subcomplexes (40S, 60S, 80S and polysomes). Here, we develop polysome proteome profiling to obtain unbiased proteomic maps across ribosomal subcomplexes. This method combines extensive fractionation by sucrose gradient centrifugation with quantitative mass spectrometry. The high resolution of the profiles allows us to assign proteins to specific subcomplexes. Phosphoproteomics on ribosome fractions reveals that phosphorylation of serine 38 in RPL12 -- a known mitotic CDK1 substrate -- is strongly depleted in polysomes. Follow-up experiments confirm that RPL12 phosphorylation regulates translation of specific subsets of mRNAs during mitosis. Together, our results show that posttranslational modification of ribosomal proteins can regulate translation.