EF-hand motifs of diacylglycerol kinase ? interact intra-molecularly with its C1 domains.

ABSTRACT: Diacylglycerol kinase (DGK) ?, which is activated by Ca(2+), contains a recoverin homology (RVH) domain, tandem repeats of two Ca(2+)-binding EF-hand motifs, two cysteine-rich C1 domains and the catalytic domain. We previously found that a DGK? mutant lacking the RVH domain and EF-hands was constitutively active and that the N-terminal region of DGK?, consisting of the RVH domain and EF-hand motifs, interacted intra-molecularly with the C-terminal region containing the C1 and catalytic domains. In this study, we narrowed down the interaction regions of DGK?. At the C-terminal region, the C1 domains are responsible for the intra-molecular interaction. At the N-terminal region, the EF-hand motifs mainly contribute to the interaction. Moreover, using highly purified EF-hand motifs and C1 domains, we demonstrate that they directly bind to each other. The co-precipitation of these two domains was clearly attenuated by the addition of Ca(2+). These results indicate that the Ca(2+)-induced dissociation of the intra-molecular interaction between the EF-hand motifs and the C1 domains of DGK? is the key event that regulates the activity of the enzyme.

SUBMITTER: Yamamoto T 

PROVIDER: S-EPMC4050180 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature