Figure 3. Quantitative anatomy of a HeLa cell.
(A) Schematic diagram of a cell where compartments are approximately scaled by their relative contributions to total cell protein mass (not by their volumes). All membranous organelles combined (excluding the nucleus) contribute ca. 16%. For comparison, ribosomes and proteasomes contribute 6% and 1.3%, respectively. The proportion of the ER fraction would increase from 4.4% to ca. 5.4% if attached ribosomes were included. (B) Proteins of major organelles were ranked in order of decreasing abundance, and plotted against their cumulative mass. Very few proteins contribute the majority of organellar protein mass in all three cases. (C–E) Top 20 most abundant proteins in each of the three major organelles, plotted against their contribution to protein organelle mass. The complete quantitative composition of ER, mitochondria, and plasma membrane are shown in Supplementary file 5.