Protein kinase Cζ regulates phospholipase D activity in rat-1 fibroblasts expressing the α1Aadrenergic receptor

✍ Scribed by Jean-Hugues Parmentier; Gautam K Gandhi; Monique T Wiggins; Abdelwahab E Saeed; Sylvain G Bourgoin; Kafait U Malik

• Publisher: BioMed Central
• Year: 2004
• Tongue: English
• Weight: 513 KB
• Volume: 5
• Category: Article
• ISSN: 1471-2121
• DOI: 10.1186/1471-2121-5-4

✦ Synopsis

Background:

Phenylephrine (phe), an alpha1 adrenergic receptor agonist, increases phospholipase d (pld) activity, independent of classical and novel protein kinase c (pkc) isoforms, in rat-1 fibroblasts expressing alpha1a adrenergic receptors. the aim of this study was to determine the contribution of atypical pkczeta to pld activation in response to phe in these cells.

Results:

Phe stimulated a pld activity as demonstrated by phosphatidylethanol production. phe increased pkczeta translocation to the particulate cell fraction in parallel with a time-dependent decrease in its activity. pkczeta activity was reduced at 2 and 5 min and returned to a sub-basal level within 10-15 min. ectopic expression of kinase-dead pkczeta, but not constitutively active pkczeta, potentiated pld activation elicited by phe. a cell-permeable pseudosubstrate inhibitor of pkczeta reduced basal pkczeta activity and abolished phe-induced pld activation.

Conclusion:

Alpha1a adrenergic receptor stimulation promotes the activation of a pld activity by a mechanism dependent on pkczeta; our data also suggest that catalytic activation of pkczeta is not required for pld stimulation.