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Comparison of phospholipase D activity in vasopressin‐ and phorbol ester‐stimulated fibroblasts
Author(s) -
Huang Chunfa,
Wykle Robert L.,
Cabot Myles C.
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)80054-x
Subject(s) - phorbol ester , vasopressin , chemistry , phospholipase d , phospholipase c , phorbol , microbiology and biotechnology , biochemistry , protein kinase c , endocrinology , biology , enzyme
Phospholipase D (PLD) activation by vasopressin (VP) was compared to activation by TPA in REF52 cells prelabeled with [ 3 H]glycerol and [ 14 C]myristic acid. Upon VP‐treatment, the formation of [ 3 H] and [ 14 c]phosphatidic acid (PA) and phosphatidylethanol (PEt) was accompanied by the loss of radioactivity from PC and PI. However, upon TPA‐treatment, radioactivity was lost from PC only. No significant changes of phosphatidylethanolamine and phosphatidylserine were detected in the same samples. The inclusion of 5μM staurosporine for 10 min diminished the production of [ 3 H]PEt and [ 14 C]PEt by 27% and 53% in VP‐treated cells, and by 100% and 75% in TPA‐treated cells, respectively. Adding 1 mM EGTA to chelate extracellular Ca 2+ inhibited [ 3 H]PEt by approximately 31% and [ 14 C]PEt by 17% after VP‐stimulation. In contrast, EGTA had no effeet on TPA‐stimulation. The data suggest that REF52 cells contain dual PLD activities. The first is stimulated only by VP, requires Ca 2+ and hydrolyzes PI. The second is stimulated by both TPA and VP, activated by protein kinase C and hydrolyzes PC.