EF-hand motif found in phosphoinositide phospholipase C eta 1 (PI-PLC-eta1)
PI-PLC-eta1, also termed 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase eta-1, or phospholipase C-eta-1 (PLC-eta-1), or phospholipase C-like protein 3 (PLC-L3), is a neuron-specific PI-PLC that is most abundant in the brain, particularly in the hippocampus, habenula, olfactory bulb, cerebellum, and throughout the cerebral cortex. It is also expressed in the zona incerta and in the spinal cord. PI-PLC-eta1 may perform a fundamental role in the brain. It may also act in synergy with other PLC subtypes. For instance, it is activated via intracellular Ca2+ mobilization and then plays a role in the amplification of GPCR (G-protein-coupled receptor)-mediated PLC-beta signals. In addition, its activity can be stimulated by ionomycin. PI-PLC-eta1 contains an N-terminal pleckstrin homology (PH) domain, four atypical EF-hand motifs, a PLC catalytic core domain, a C2 domain, and a unique C-terminal tail that terminates with a PDZ-binding motif, a potential interaction site for other signaling proteins. The PLC catalytic core domain is a TIM barrel with two highly conserved regions (X and Y) split by a highly degenerate linker sequence. The C-terminal tail harbors a number of proline-rich motifs which may interact with SH3 (Src homology 3) domain-containing proteins, as well as many serine/threonine residues, suggesting possible regulation of interactions by protein kinases/phosphatases.