Consecutive steps in the phosphatidic acid biosynthesis pathway in Arabidopsis pollen tube during pollination. (1). The gene locus, AT4G01190 encodes 1-phosphatidylinositol-4-phosphate 5-kinase, PIP5K (EC: 2.7.1.68) catalyzing the conversion of PtdIns4P to PtdIns(4,5)P2. (2). The gene locus, AT3G55940 encodes phosphoinositide phospholipase C, PLC (EC: 3.1.4.11) catalyzing the conversion of PtdIns(4,5)P2 to Ins(1,4,5)P3. (3). The gene locus, AT1G05630 encodes an inositol polyphosphate 5-phosphatase (EC: 3.1.3.56) with phosphatase activity toward only Ins(1,4,5)P3.