SCF- and FL-mediated Erk and S6 signal shape analysis. Response indicates percentage of responding cells with t = 0 level subtracted. Individual signaling profiles were normalized to t = 0 (equal to 0 response) and the largest value (maximum). t½_{Erk/S6 rise} indicates time to 50% of maximum; and t½_{Erk/S6 decay}, time to 50% loss of maximum. Gray zones represent 95% CI for t½_{Erk rise} (A-B) and t½_{Erk decay} (C). The response shapes for S6 phosphorylation were not significantly different (D). Error bars represent 95% CI.