TABLE 1.

Ras-GTP loading in response to EGF^a

Cell line	Stimulationb
WT	2.64
K721R	0.75
Y740F	1.28
V741G	2.51
CT957	1.29

^aQuiescent cells (5 × 10⁶ per cell line) were loaded with [α-³²P]GTP by electroporation prior to incubation with buffer only or with EGF (100 ng/ml) for 5 min at 37°C. Ras-associated [α-³²P]GTP was determined as described in Materials and Methods. 

^bExpressed as the ratio between [α-³²P]GTP in EGF-treated samples and that in control samples.