Table 2. Alterations in K_M in Saturation Kinetic Studies of CHT and LV-AA Following PMA and Staurosporine Treatment of the HEK293 Stable Cell Line^a.

cell line	treatment	KM (mean ± SEM)	fold change
hCHT	none	19.26 ± 9.1
hCHT LV-AA	none	21.13 ± 9.0
hCHT	PMA (1 μM)	9.72 ± 4.3(*)	1.98-fold decrease from untreated WT
hCHT LV-AA	PMA (1 μM)	17.3 ± 4.1
hCHT	Stauro. (5 μM)	4.45 ± 2.8(**)	4.3-fold decrease from untreated WT
hCHT LV-AA	Stauro. (5 μM)	11.91 ± 4.4(*)	1.7-fold decrease from untreated LV

^aTreatment with PMA had a significant impact on K_M of the CHT cell line. Treatment with staurosporine reduced the K_M of both the CHT and the CHT LV-AA cell lines. These results imply that the uptake increases measured with staurosporine are not due to increased trafficking of the transporter but are more likely due to an increase in kinetic efficiency of the transporter. These measurements are the combined analysis of n = 4–5 trials in triplicate. Significant change was determined by Student’s t-test analysis of all trials and reported next to values as *–*** for p values less than 0.5–0.01. Standard error between replicates is less than 10% (data not shown).