tokens: The AP - 1 recruited by ARF1 . GTP is released from the Golgi membrane by treatment with 1 M Tris - HCl ( pH 7 ) or upon reincubation at 37 degreesC , whereas AP - 1 recruited with GTPgammaS or by a constitutively active point mutant , ARF1 ( Q71L ) , remains membrane bound after either treatment .