Fig. 5: Differential clearance of phosphopeptides is not predictive of effects of phosphorylation on a protein’s proteolytic stability.
a Experimental setup for interrogating effects of phosphosite mutations on protein proteolytic stability. Turnover of exogenously expressed proteins was quantified from TMT signal sums of the old protein from pull-down experiments, and compared to the turnover of a corresponding, similarly-tagged and expressed wild-type (WT) construct. b Comparison of differences in clearance rates from PPToP (Δkapp) and wild-type-to-mutant differences (Δkdeg) from the exogenous expression experiment show no significant correlation (see also Supplementary Fig. 6b), indicating that differences in clearance measured from PPToP are not predictive of differences in protein degradation caused by the PTM. c Phospho PPToP hits are not enriched for being proximal to predicted degrons25. Proximity was defined by considering whether any part of a predicted degron overlaps with a 31 amino acid stretch centered on the measured peptide. Fisher’s exact test, two-sided. d No known degrons26 lie proximal to the measured Phospho PPToP hits. Source data are provided as a Source data file.
