Regulation of cytoskeletal dynamics by phospholipase D and phosphatidic acid

• Phosphatidic acid and phospholipase D are key regulators of cytoskeletal organization.
• Two cytoskeletal-associated proteins have been identified as PA-binding proteins.
• Genetic evidence indicates that CP and MAP65-1 are PA sensors in live plant cells.
• Emerging models for PLD–PA–cytoskeleton crosstalk are highlighted.

Plants respond to diverse biotic and abiotic stimuli as well as to endogenous developmental cues. Many of these stimuli result in altered activity of phospholipase D (PLD), an enzyme that hydrolyzes structural phospholipids producing phosphatidic acid (PA). PA is a key signaling intermediate in animals, but its targets in plants are relatively uncharacterized. Recent studies have demonstrated that the cytoskeleton is a major target of PLD–PA signaling and identified a positive feedback loop between actin turnover and PLD activity. Moreover, two cytoskeletal proteins, capping protein and MAP65-1, have been identified as PA-binding proteins regulating actin and microtubule organization and dynamics. In this review, we highlight the role of the PLD–PA module as an important hub for housekeeping and stress-induced regulation of membrane-associated cytoskeletal dynamics.