first protein kinase C conserved region 1 (C1 domain) found in type IV diacylglycerol kinases
Diacylglycerol (DAG) kinase (EC 18.104.22.168) is a lipid kinase that phosphorylates diacylglycerol to form phosphatidic acid. Type IV DAG kinases (DGKs) contain myristoylated alanine-rich protein kinase C substrate (MARCKS), PDZ-binding, and ankyrin domains, in addition to C1 and catalytic domains that are present in all DGKs. The MARCKS domain regulates the nuclear localizations of type IV DGKs while the PDZ-binding and ankyrin domains regulate interactions with several proteins. Two DGK isozymes (zeta and iota) are classified as type IV. DAG kinase zeta, also called diglyceride kinase zeta (DGK-zeta), displays a strong preference for 1,2-diacylglycerols over 1,3-diacylglycerols, but lacks substrate specificity among molecular species of long chain diacylglycerols. DAG kinase iota, also called diglyceride kinase iota (DGK-iota), or DGKI, is a homolog of Drosophila DGK2, RdgA. It may have important cellular functions in the retina and brain. Members of this family contain two copies of the C1 domain. This model corresponds to the first one. 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.