Heterogeneity of diacylglycerol kinase in terms of molecular structure, biochemical characteristics and gene expression localization in the brain.
Three different cDNA clones for diacylglycerol (DG) kinase were isolated from a rat brain cDNA library and designated DGK-I, DGK-II and DGK-III. These three encode distinct polypeptides with 58% identity to each other and contain EF-hand motifs, cysteine-rich zinc finger-like sequences and putative ATP-binding sites. A high kinase activity is shown in COS cells transfected with either one of the three cDNAs without substrate specificity among DG species, and the kinase activity is Ca-dependent. The activity for DGK-I is recovered dominantly in the soluble fraction of the cell, that for DGK-II in the particulate fraction; and that for DGK-III equally in both of the fractions. The difference in their expression localization is most noticeable: DGK-I is expressed in oligodendrocytes of the brain as well as T-lymphocytes in the thymus and spleen; DGK-II is expressed in neurons of the caudate-putamen, accumbens nucleus and olfactory tubercle; and DGK-III in the cerebellar Purkinje cells and granule cells. The functional significance of the discovery of three DG kinase isozymes is briefly discussed.
Department of Anatomy, Tohoku University School of Medicine, Sendai, Japan.
K
K
Goto
H
H
Kondo
D000818:Animals; D001921:Brain / Q000201:enzymology*; D019852:Diacylglycerol Kinase; D015971:Gene Expression Regulation, Enzymologic; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D051381:Rats
D017853:Phosphotransferases (Alcohol Group Acceptor); D019852:Diacylglycerol Kinase