Effect of Different Inhibitors on Phospholipase C Activity in Catharanthus roseus Transformed Roots

• Published in: Prostaglandins & other lipid mediators 1998-05, Vol.56 (1), p.19-31
• Main Authors: Piña-Chable, Marı́a Luisa, De Los Santos-Briones, César, Muñoz-Sánchez, J.Armando, Machado, Ileana Echevarrı́a, Hernández-Sotomayor, S.M.Teresa
• Format: Article
• Language: English
• Subjects: CATHARANTHUS ROSEUS; Copper - pharmacology; ENZYME INHIBITORS; GENETIC TRANSFORMATION; INHIBIDORES DE ENZIMAS; INHIBITEUR D'ENZYME; Inositol 1,4,5-Trisphosphate - analysis; IP 3, inositol 1,4,5,trisphosphate; NEOMICINA; NEOMYCIN; Neomycin - pharmacology; NEOMYCINE; Nickel - pharmacology; Phosphatidylinositol 4,5-Diphosphate - metabolism; phospholipase C inhibition; PI, phosphatidylinositol; PIP 2, phosphatidylinositol 4,5-bisphosphate; PIP, phosphatidylinositol monophosphate; Plant Roots - enzymology; plant signal transduction. ABBREVIATIONS: C. roseus, Catharanthus roseus; Plants - enzymology; PLC, phospholipase C; Protein Synthesis Inhibitors - pharmacology; Putrescine - pharmacology; Rhizobium - physiology; Signal Transduction; Space life sciences; Spermidine - pharmacology; Spermine - pharmacology; TRANSFORMACION GENETICA; TRANSFORMATION GENETIQUE; Type C Phospholipases - antagonists & inhibitors; Type C Phospholipases - metabolism; Zinc - pharmacology
• ISSN: 1098-8823
• DOI: 10.1016/S0090-6980(98)00037-9

We have previously reported that Catharanthus roseus transformed roots contain at least two phosphatidylinositol 4,5-bisphosphate-phospholipase C (PLC) activities, one soluble and one membrane associated. In this paper, the effect of neomycin and several divalent cations was analyzed, both in the soluble and the membrane-associated PLC activity in C. roseus transformed roots. In this system, neomycin, an aminoglycoside antibiotic, inhibited PLC in a concentration-dependent fashion. The neomycin IC 50 (100 μM) was the same for the inhibition of the soluble and the membrane associated PLC activity. The effect of different divalent cations such as Ni 2+, Cu 2+, and Zn 2+ was studied as well. In order to see the effect of these cations on PLC activity, we selected two conditions: a) in the presence of and b) in the absence of calcium. In the presence of calcium, these three divalent cations were able to inhibit PLC activity in both fractions in a concentration-dependent manner; however, the IC 50s were different for the membrane and the soluble activities. For the soluble activity, the inhibition due to the three cations was very similar (IC 50s between 0.2 and 0.3 mM). For the membrane associated PLC activity, Cu 2+ was the most potent inhibitor (IC 50 3.6 μM), then Ni 2+ and then Zn 2+. In the absence of calcium, higher cocentrations of Cu 2+ and Zn 2+ demonstrated some inhibitory effect. We discuss the possible physiological role of these inhibitors on PLC activity.