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Effects of okadaic acid on the activities of two distinct phosphatidate phosphohydrolases in rat hepatocytes
Author(s) -
Gomez-Muñoz Antonio,
Hatch Grant M.,
Martin Ashley,
Jamal Zahirali,
Vance Dennis E.,
Brindley David N.
Publication year - 1992
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(92)80219-7
Subject(s) - okadaic acid , phosphatidate , cytosol , diacylglycerol kinase , biochemistry , chemistry , phospholipase a2 , phospholipase , phosphatase , phospholipase c , enzyme , incubation , protein kinase c
Incubation of hepatocytes with okadaic acid displaced the N ‐ethylmaleimide‐sensitive phosphatidate phosphohydrolase from the membrane fraction into the cytosol and partially prevented the oleate‐induced movement of phosphohydrolase from cytosol to membranes. However, higher concentrations of oleate still caused translocation and activation of the phosphohydrolase. This enzyme is stimulated by Mg 2+ , and is probably involved in glycerolipid synthesis. Okadaic acid also decreased the concentration of diacylglycerol within the hepatocytes. Okadaic acid had no observable effect on the activity of an N ‐ethylmaleimide‐insensitive phosphatidate phosphohydrolase which remained firmly attached to membranes. This activity is not stimulated by Mg 2+ and is probably involved in signal transduction by the phospholipase D pathway.