PORCINE DIACYLGLYCEROL KINASE SEQUENCE HAS ZINC FINGER AND E-F HAND MOTIFS

CELL stimulation causes diacylglycerol kinase (DGK) to convert the second messenger diacylglycerol into phosphatidate, thus initiating the resynthesis of phosphatidylinositols and attenuating protein kinase C activity1. Of the DGK isoforms so far reported2-4, only porcine DGK from lymphocytes5 has been characterized in detail3,5-7. Here we report the isolation and sequencing of complementary DNA clones that together cover the entire region encoding porcine DGK (relative molecular mass 80,000 (80K)). The deduced primary structure of this DGK contains the putative ATP-binding sites, two cysteine-rich zinc finger-like sequences similar to those found in protein kinase C8, and two E-F hand motifs, typical of Ca2+-binding proteins like calmodulin9. Indeed, we find that the activity of this DGK isoform is enhanced by micromolar concentrations of Ca2+ in the presence of deoxycholate or sphingosine. These properties of 80K DGK indicate that its action is probably linked with both of the second messengers diacylglycerol10 and inositol 1,4,5-trisphosphate11. © 1990 Nature Publishing Group.