Figure 5.

sAC is active in HEK293 cells. (A) Adenylyl cyclase activity in the presence of 5 mM MnCl₂ or 5 mM MgCl₂ is shown for cytosolic and particulate extracts from HEK293 cells transiently transfected with pBK-CMV vector (░⃞), full-length sAC gene (▨), or truncated sAC gene (▧). Values are expressed as pmols of cAMP formed per minute per mg protein and represent averages of triplicate determinations. Error bars indicate the standard deviation from the mean. Note the 20-fold difference in scale of the ordinate between left and right panels. (B) sAC activity in whole-cell sonicates from HEK293 cells transfected with full-length sAC (Left) or truncated sAC (Right) assayed in the absence of any activators (░⃞) or in the presence of 100 μM forskolin (▨) or 5 mM GTPγS (□). Values represent the averages of quadruplicate determinations with vector transfected HEK293 values for each condition subtracted. Error bars indicate the standard deviation from the mean.