The Arabidopsis Phospholipase D Family. Characterization of a Calcium-Independent and Phosphatidylcholine-Selective PLDζ1 with Distinct Regulatory Domains

Abstract

Four types of phospholipase D (PLD), PLD␣, ␤, ␥, and ␦, have been characterized in Arabidopsis, and they display different requirements for Ca 2ϩ , phosphatidylinositol 4,5-bisphosphate (PIP 2), substrate vesicle composition, and/or free fatty acids. However, all previously cloned plant PLDs contain a Ca 2ϩ-dependent phospholipid-binding C2 domain and require Ca 2ϩ for activity. This study documents a new type of PLD, PLD1, which is distinctively different from previously characterized PLDs. It contains at the N terminus a Phox homology domain and a pleckstrin homology domain, but not the C2 domain. A full-length cDNA for Arabidopsis PLD1 has been identified and used to express catalytically active PLD in Escherichia coli. PLD1 does not require Ca 2ϩ or any other divalent cation for activity. In addition, it selectively hydrolyzes phosphatidylcholine, whereas the other Arabidopsis PLDs use several phospholipids as substrates. PLD1 requires PIP 2 for activity, but unlike the PIP 2-requiring PLD␤ or ␥, phosphatidylethanolamine is not needed in substrate vesicles. These differences are described, together with a genomic analysis of 12 putative Arabidopsis PLD genes that are grouped into ␣, ␤, ␦, ␥, and based on their gene architectures, sequence similarities, domain structures, and biochemical properties.

The Phosphate Fast-Responsive Genes PECP1 and PPsPase1 Affect Phosphocholine and Phosphoethanolamine Content

“…A connection between choline content and root hair elongation was also suggested following the mutation of PLDz1, an enzyme responsible for the degradation of PtdCho into PA and choline (Qin and Wang, 2002;Ohashi et al, 2003). However, the double KO pldz1 pldz2 contradicted these results since it did not exhibit any root hair alteration (Li et al, 2006).…”

“…To verify if altered levels of PCho and PEth could lead to the transcriptomic activation or inhibition of specific lipid metabolism pathways, we selected several genes representative of membrane lipid recycling pathways triggered during Pi starvation (Nakamura, 2013). These genes included NPC4 (representative of the nonspecific PLC pathway; Nakamura et al, 2005), PLDz1 and 2, PAH1 and 2 (for the PLD/PAP pathway; Qin and Wang, 2002;Li et al, 2006;Nakamura et al, 2009;Eastmond et al, 2010), and GDPD1, 2, 3, 5, and 6 (for the LAH/GDPD pathway; Cheng et al, 2011). In response to a lack of Pi, we observed that NPC4, PLDz2, and GDPD1, 2, 3, 5, and 6 were induced in wild-type plants as previously reported (Supplemental Fig.…”

“…Previous studies have reported altered root architecture and epidermal cell death in a XIPOTL1/PEAMT1 KO mutant (xpl1; Cruz-Ramírez et al, 2004). However, even though PCho content was effectively diminished in this mutant, the described phenotype was more likely caused by an impaired balance of choline, PtdCho, and phosphatidic acid (Cruz-Ramírez et al, 2004; AlatorreCobos et al, 2012).A connection between choline content and root hair elongation was also suggested following the mutation of PLDz1, an enzyme responsible for the degradation of PtdCho into PA and choline (Qin and Wang, 2002;Ohashi et al, 2003). However, the double KO pldz1 pldz2 contradicted these results since it did not exhibit any root hair alteration (Li et al, 2006).…”

Desaturase mutants reveal that membrane rigidification acts as a cold perception mechanism upstream of the diacylglycerol kinase pathway in Arabidopsis cells

“…We compared them to the radioactive molecular species of PtdIns, PtdEtn and PtdCho after a 24 h 33 Pi labeling that reflect the molecular species distribution of the bulk lipids (not shown). The molecular species of radioactive PtdOH after a 10 min cold stress were typical of phosphoinositides, confirming that this radioactive PtdOH resulted almost exclusively from a DAGK activity coupled with phosphoinositide-dependent phospholipase C (PI-PLC) activity as PtdIns is not a substrate of Arabidopsis PLD [22].…”

Genome-wide analysis and expression profiling of the phospholipase D gene family in Gossypium arboreum

“…According to the sequence characteristics, the PLD gene family can be generally classified into six or seven types, including PLD, PLD, PLD, PLD, PLD, PLD and/or PLD (Elias et al, 2002;Li et al, 2007). The diverse PLD types differentiated depending on their requirements and affinities for Ca 2+ , phosphatidylinositol 4,5-bisphosphate (PIP 2 ) and free fatty acids (Qin and Wang, 2002;Qin et al, 1997). The exception was PLD, which was poorly characterized as of yet (Li et al, 2007).…”