Lipidomics of phospholipase A reveals exquisite specificity in macrophages.

Phospholipase A (PLA) constitutes a superfamily of enzymes that hydrolyze phospholipids at their sn-2 fatty acyl position. Our laboratory has demonstrated that PLA enzymes regulate membrane remodeling and cell signaling by their specificity toward their phospholipid substrates at the molecular level. Recent in vitro studies show that each type of PLA, including Group IVA cytosolic PLA (cPLA), Group V secreted PLA (sPLA), Group VIA calcium independent PLA (iPLA) and Group VIIA lipoprotein-associated PLA, also known as platelet-activating factor acetyl hydrolase, can discriminate exquisitely between fatty acids at the sn-2 position.

Publisher Correction: Sphingolipid biosynthesis modulates plasmodesmal ultrastructure and phloem unloading.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Sphingolipid biosynthesis modulates plasmodesmal ultrastructure and phloem unloading.

During phloem unloading, multiple cell-to-cell transport events move organic substances to the root meristem. Although the primary unloading event from the sieve elements to the phloem pole pericycle has been characterized to some extent, little is known about post-sieve element unloading. Here, we report a novel gene, PHLOEM UNLOADING MODULATOR (PLM), in the absence of which plasmodesmata-mediated symplastic transport through the phloem pole pericycle-endodermis interface is specifically enhanced.

Loss of Inositol Phosphorylceramide Sphingolipid Mannosylation Induces Plant Immune Responses and Reduces Cellulose Content in Arabidopsis.

Glycosylinositol phosphorylceramides (GIPCs) are a class of glycosylated sphingolipids found in plants, fungi, and protozoa. These lipids are abundant in the plant plasma membrane, forming ∼25% of total plasma membrane lipids. Little is known about the function of the glycosylated headgroup, but two recent studies have indicated that they play a key role in plant signaling and defense.