Fig. 5.

Multiplexed quantitative assays of pluripotency pathway components. A, heat map showing estimated protein abundance of Jak1, STAT3, STAT1, Akt1, and LIFR in cytoplasmic extracts from pluripotent mESC populations based on two endogenous or spiked peptides (1 and 2) measured by MRM. Inset, representative (untransformed) relative intensity (y axis). B, pathway schematic showing experimental XIC values (I, intensity) obtained for peptides corresponding to endogenous Sall4, Pou5f1, and Sox2 levels in nuclear and cytoplasmic extracts from +LIF (self-renewal; red) and −LIF (differentiation; green) treated mESCs. C, actual protein abundance measurements of pluripotency factors in +LIF and −LIF mESC NEs as obtained by targeted LC-MS/MS experiments (TPM) on an LTQ-ion trap.