Phorbol esters (such as PMA) are analogues of DAG and potent tumor promoters that cause a variety of physiological changes when administered to both cells and tissues. DAG activates a family of serine/threonine protein kinases, collectively known as protein kinase C (PKC). Phorbol esters can directly stimulate PKC.
The N-terminal region of PKC, known as C1, binds PMA and DAG in a phospholipid and zinc-dependent fashion. The C1 region contains one or two copies of a cysteine-rich domain, which is about 50 amino-acid residues long, and which is essential for DAG/PMA-binding.
The DAG/PMA-binding domain binds two zinc ions; the ligands of these metal ions are probably the six cysteines and two histidines that are conserved in this domain.
- C1 domains in SMART
- C1 domains in Pfam
- UMich Orientation of Proteins in Membranes families/superfamily-63 - Orientations of C1 domains in membranes (OPM)