second protein kinase C conserved region 1 (C1 domain) found in type I diacylglycerol kinases
Diacylglycerol (DAG) kinase (EC 2.7.1.107) is a lipid kinase that phosphorylates diacylglycerol to form phosphatidic acid. Type I DAG kinases (DGKs) contain EF-hand structures that bind Ca(2+) and recoverin homology domains, in addition to C1 and catalytic domains that are present in all DGKs. Type I DGKs, regulated by calcium binding, include three DGK isozymes (alpha, beta and gamma). DAG kinase alpha, also called 80 kDa DAG kinase, or diglyceride kinase alpha (DGK-alpha), is active upon cell stimulation, initiating the resynthesis of phosphatidylinositols and attenuating protein kinase C activity. DAG kinase beta, also called 90 kDa DAG kinase, or diglyceride kinase beta (DGK-beta), exhibits high phosphorylation activity for long-chain diacylglycerols. DAG kinase gamma, also called diglyceride kinase gamma (DGK-gamma), reverses the normal flow of glycerolipid biosynthesis by phosphorylating diacylglycerol back to phosphatidic acid. Members of this family contain two copies of the C1 domain. This model corresponds to the second one. DGK-alpha contains atypical C1 domains, while DGK-beta and DGK-gamma contain typical C1 domains that bind DAG and phorbol esters. The C1 domain is a cysteine-rich zinc binding domain that does not bind DNA nor possess structural similarity to conventional zinc finger domains; it contains two separate Zn(2+)-binding sites.
Jiyao W et al.(2023). "The conserved domain database in 2023.",