Table II. SRM-based measurement of six EGFR-associated proteins.

Cells stably expressing FLAG-tagged wild type receptor (EGFR) or the S991A and Y998F EGFR proteins (as indicated) were treated with or without EGF (100 ng/ml) for 15 min at 37 °C. Anti-FLAG immune complexes were digested with trypsin and analyzed by SRM (“Experimental Procedures”). Protein name and peptide sequence are indicated in the first two columns, respectively. The third column indicates the m/z values for the Q1-to-Q3 transitions that were monitored. In columns 4–12, the EGF-induced -fold change in abundance of associated proteins is indicated for the WT EGFR and the indicated variant receptors. -Fold changes are presented as the mean of n = 3 independent experiments with CV and S.E. and correspond to the histogram presented in Fig. 5.

Protein	Peptide	Q1/Q3 transition	WT			Y998F			S991A
			Mean	CV	S.E.	Mean	CV	S.E.	Mean	CV	S.E.
CBL	GTEPIVVDPFDPR	721.37/631.3	7.46	0.46	1.97	4.21	0.55	1.33	4.86	0.42	1.19
GRB2	FNSLNELVDYHR	753.87/802.4	3.15	0.23	0.42	3.10	0.45	0.81	2.99	0.33	0.57
SHC1	GLLVPALK	405.78/428.3	2.85	0.31	0.51	1.87	0.42	0.45	2.21	0.59	0.75
VAV2	HLLLVDPEGVVR	673.89/656.4	1.40	0.19	0.16	1.51	0.19	0.17	1.38	0.39	0.31
UBB	SHASGTYLIR	552.79/880.5	3.28	0.33	0.63	3.80	0.26	0.57	2.49	0.36	0.52
SOS1	TITLEVEPSDTIENVK	894.47/1131.6	1.91	0.28	0.31	1.63	0.25	0.23	1.53	0.41	0.36