first protein kinase C conserved region 1 (C1 domain) found in the protein kinase D (PKD) family
PKDs are important regulators of many intracellular signaling pathways such as ERK and JNK, and cellular processes including the organization of the trans-Golgi network, membrane trafficking, cell proliferation, migration, and apoptosis. They are activated in a PKC-dependent manner by many agents including diacylglycerol (DAG), PDGF, neuropeptides, oxidative stress, and tumor-promoting phorbol esters, among others. Mammals harbor three types of PKDs: PKD1 (or PKCmu), PKD2, and PKD3 (or PKCnu). PKDs contain N-terminal tandem cysteine-rich zinc binding C1 (PKC conserved region 1), central PH (Pleckstrin Homology), and C-terminal catalytic kinase domains. This model corresponds to the first C1 domain. 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.