Mass spectrometry-based absolute quantification reveals rhythmic variation of mouse circadian clock proteins
Ryohei Narumi, Yoshihiro Shimizu, Maki Ukai-Tadenuma, Koji L. Ode, Genki N. Kanda, Yuta Shinohara, Aya Sato, Katsuhiko Matsumoto, and Hiroki R. Ueda
PNAS (2016) 113, E3461, online: May 31, 2016
This study looked at the core circadian clock proteins in a mammalian system and quantified them with multiplexed SRM-based targeted proteomics. The authors used LC/MS-based "quantification by isotope labeled cell-free products" (MS-QBiC). This method uses a reconstituted cell-free protein synthesis system for high-throughput preparation of internal standards.
After 2 weeks of light/dark conditioning of the mice, livers were collected and analyzed at 6 time points using 120 QBiC peptides. Sixteen proteins from 20 selected circadian clock proteins were successfully quantified from the mouse livers over a 24-h time series, and 14 proteins had circadian variations. The study also demonstrated that single-time-points can predict body time, showing that expression levels of each circadian protein are potential markers for body time detection in human samples. |