<p>This short domain is rich in cysteines and histidines. The pattern of conservation is similar to that found in <db_xref db="INTERPRO" dbkey="IPR002219"/>. C1 domains are protein kinase C-like zinc finger structures. Diacylglycerol (DAG) kinases (DGKs) have a two or three commonly conserved cysteine-rich C1 domains [<cite idref="PUB00044044"/>]. DGKs modulate the balance between the two signaling lipids, DAG and phosphatidic acid (PA), by phosphorylating DAG to yield PA [<cite idref="PUB00044045"/>].</p><p>The PKD (protein kinase D) family are novel DAG receptors. They have twin C1 domains, designated C1a and C1b, which bind DAG or phorbol esters. Individual C1 domains differ in ligand-binding activity and selectivity [<cite idref="PUB00044046"/>].</p> C1-like