Extended Data Fig. 5: Aggregation and degradation propensity of individual complex subunits.

a, Stability of individual complex subunits, tagged by GFP, determined by CHX chase, in wild-type and deletion strains expressing orphan complex subunit. Cells with GFP fluorescence were analysed by FACS. Mean GFP fluorescence ± s.e.m. are presented with each data point from three biologically independent experiments overlaid. In each experiment, 20,000 events were recorded. **P = 0.0253, two tailed t-test. b, Solubility of individual complex subunits, tagged by GFP, determined by localization patterns changes, in wild-type and in deletion strains expressing orphan complex subunit. Log-phase cells (30 °C) were fixed and analysed by confocal microscopy (left). A representative image is shown. Scale bar, 4 μm. The fraction of cells displaying foci of GFP-tagged subunit per cell was quantified (right) (n = 155 cells per sample; from three biologically independent experiments). Data are mean ± s.e.m. overlaid with each data point. c, Subunit aggregation is complex-specific. Solubility of the Naa15–GFP subunit of the NatA complex in trp2∆ mutant cells deleted for the Trp2 subunit of the TRP complex, analysed as in b. (n = 155 cells/sample; from three biologically independent experiments). Data are mean ± s.e.m. overlaid with each data point. **P = 1.367248 × 10⁻¹¹ (middle) and P = 7.850135 × 10⁻¹⁰ of a (lower panel) of a two tailed t-test. d, Characteristics of cotranslational complex assembly interactions. Left, zoom-in on the first 400 codons, displaying the onset and persistence of cotranslational interaction of each subunit with its partner subunit or subunits, for all 14 subunits identified as cotranslationally engaged. Right, the corresponding normalized length of each ORF at the onset of cotranslational interactions with partner subunits, demonstrating the length variability at the onset position.