Phosphatidylcholine-specific phospholipase D activity is elevated in v-Fps-transformed cells

Area of Science:

• Cell biology
• Biochemistry
• Signal transduction

Background:

• The protein-tyrosine kinase v-Fps plays a role in cellular signaling.
• Diglyceride (DG) is a key lipid second messenger involved in various cellular processes.
• Phosphatidylcholine (PC) is a major phospholipid in cell membranes.

Purpose of the Study:

• To investigate the mechanism of v-Fps-induced diglyceride (DG) production.
• To determine the source and pathway of DG generation following v-Fps activation.

Main Methods:

• Rat fibroblasts were utilized to study v-Fps kinase activity.
• Phospholipids were prelabeled with [3H]-myristate to trace metabolic pathways.
• Inhibition of phosphatidic acid phosphatase (PAP) was employed to assess its role in DG production.
• Phospholipase D (PLD) activity was measured in response to v-Fps activation.

Main Results:

• Activation of v-Fps kinase led to a rapid increase in DG levels in rat fibroblasts.
• v-Fps-induced DG production was dependent on phosphatidylcholine (PC) as the precursor.
• Inhibition of PAP blocked the accumulation of DG.
• PLD activity was significantly activated upon v-Fps kinase activation, particularly when cells were labeled with PC-specific [3H]-myristate.

Conclusions:

• v-Fps-induced DG is primarily derived from phosphatidylcholine (PC).
• The phospholipase D (PLD) and phosphatidic acid phosphatase (PAP) pathway is responsible for v-Fps-mediated DG production.
• These findings elucidate a novel signaling pathway involving v-Fps and lipid metabolism.