Polyamines modify the components of phospholipids-based signal transduction pathway in Coffea arabica L. cells

Recent results, fundamentally obtained from animal tissues, suggest that polyamines (Pas), essential compounds for the growth and development of all life organisms, may interact with a signal transduction cascade. Because Pas are highly positive charged compounds, their binding with phospholipids involved in signal transduction is likely to be the case. In this work, the in vivo effect of Pas on some important components of phospholipid signal transduction pathway was studied, by the first time, in plant tissue. Endogenous Pas content varied during the culture cycle of Coffea arabica cells: putrescine (Put) levels increased at the end of the stationary phase, both spermidine (Spd) and spermine (Spm) accumulated at the beginning of the linear growth phase. Cells that were incubated with Put presented a significant increase in phospholipase D (PLD) (EC: 3.1.4.4) activity, phospholipase C (PLC) (EC: 3.1.4.3) activity decreased, and the effect on lipid kinases was less marked. However, the incubation of the cells with Spd and Spm significantly stimulated the lipid kinases activities, fundamentally increased the formation of phosphatidyl inositol 4-phosphate (PIP) and phosphatidylinositol 4,5-bisphosphate (PIP2), while the effect on PLC and PLD activities was minor when compared with the cells treated with Put. The results presented here suggest that Pas may modulate the cellular signal of C. arabica cells by differentially affecting components of the phospholipid cascade.