Research article
Protein kinase Cζ regulates phospholipase D activity in rat-1 fibroblasts expressing the α1A adrenergic receptor
1 Department of Pharmacology and Center for Connective Tissue Diseases and Vascular Biology, College of Medicine, The University of Tennessee Health Science Center, 874 Union Avenue, Memphis, TN 38163, USA
2 Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du CHUQ, Universite Laval, Sainte-Foy, QC, Canada
BMC Cell Biology 2004, 5:4 doi:10.1186/1471-2121-5-4
Published: 21 January 2004Abstract
Background
Phenylephrine (PHE), an α1 adrenergic receptor agonist, increases phospholipase D (PLD) activity, independent of classical and novel protein kinase C (PKC) isoforms, in rat-1 fibroblasts expressing α1A adrenergic receptors. The aim of this study was to determine the contribution of atypical PKCζ to PLD activation in response to PHE in these cells.
Results
PHE stimulated a PLD activity as demonstrated by phosphatidylethanol production. PHE increased PKCζ translocation to the particulate cell fraction in parallel with a time-dependent decrease in its activity. PKCζ activity was reduced at 2 and 5 min and returned to a sub-basal level within 10–15 min. Ectopic expression of kinase-dead PKCζ, but not constitutively active PKCζ, potentiated PLD activation elicited by PHE. A cell-permeable pseudosubstrate inhibitor of PKCζ reduced basal PKCζ activity and abolished PHE-induced PLD activation.
Conclusion
α1A adrenergic receptor stimulation promotes the activation of a PLD activity by a mechanism dependent on PKCζ; Our data also suggest that catalytic activation of PKCζ is not required for PLD stimulation.
