Figure 2.

[¹⁴C]et-eEF1A is lost from microsomes treated with 1 mm Ca²⁺, phospholipase D (PLD) or phospholipase C (PLC), but not phospholipase A₂ (PLA₂). Carrot cells were incubated with [¹⁴C]ethanolamine (10 μCi/g fresh weight) for 2 d, and harvested as described in “Materials and Methods.” The 40,000g microsomal pellet was washed, concentrated by centrifugation, and resuspended in reaction buffer. Phospholipases were added to 112 μg of membrane protein, and the reaction was incubated at 25°C with shaking (200 rpm) for 10 min. The reaction was stopped by adding ice-cold EGTA. Aliquots were removed from each reaction, and the recovery of [¹⁴C]et-eEF1A was monitored by TCA precipitation analysis. The means of four values from two experiments are reported. PI-PLC, PI-phospholipase C.