TABLE 2.

Critical parameters determining model output

		Ligand binding		Receptor dimerization		Receptor phosphorylation		Trafficking
Output variable		+	−	+	−	+	−	+	−
EGFR-EGFR	Total	1	6	15,18	13,17	23,29		47
	Surface			15,18	13,17	23,29		43,47	41,45,49–52
EGFR-HER2	Total		6	13,17		25,28,29	35,39,40
	Surface			12,17	15	25,28,29	35	43,47	41,49–51
EGFR-HER3	Total	2	6,7,11	13	18	27,28,29	38	47	41,49
	Surface		7,11	13	18	27,28,29		43,47	41,49–52
HER2-HER3	Total				17	26,28,29	37
	Surface					26,28,29	37	47	41,49

Parametric sensitivity analysis was performed by increasing each of the 54 model parameters (listed in Table 1) by 10%, one at a time, and studying the effect of this increase on the levels of activated dimers both at the whole-cell level and at the plasma membrane. Parameters that elicit a >2% change in the concentrations of the specific dimer species are listed. Parameter changes that result in an increase in the output, are listed in the plus (+) column; parameters whose increase results in a decrease in the output, are listed in the minus (−) column.