EF-hand motif found in phosphoinositide phospholipase C beta 4 (PI-PLC-beta4)
PI-PLC-beta4, also termed 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase beta-4, or phospholipase C-beta-4 (PLC-beta4), is expressed in high concentrations in cerebellar Purkinje and granule cells, the median geniculate body, and the lateral geniculate nucleus. It may play a critical role in linking anxiety behaviors and theta rhythm heterogeneity. PI-PLC-beta4 is activated by the heterotrimeric G protein alpha q subunits through their C2 domain and long C-terminal extension. It contributes to generate cell-specific Ca2+ signals evoked by G protein-coupled receptor stimulation. PI-PLC-beta4 functions as a downstream signaling molecule of type 1 metabotropic glutamate receptors (mGluR1s). The thalamic mGluR1-PI-PLC-beta4 cascade is essential for formalin-induced inflammatory pain by regulating the response of ventral posterolateral thalamic nucleus (VPL) neurons. Moreover, PI-PLC-beta4 is essential for long-term depression (LTD) in the rostral cerebellum, which may be required for the acquisition of the conditioned eyeblink response. Besides, PI-PLC-beta4 may play an important role in maintenance of the status epilepticus. The mutations of PI-PLC-beta4 has been identified as the major cause of autosomal dominant auriculocondylar syndrome (ACS). PI-PLC-beta4 contains a core set of domains, including an N-terminal pleckstrin homology (PH) domain, four atypical EF-hand motifs, a PLC catalytic core, and a single C2 domain. Besides, it has a unique C-terminal coiled-coil (CT) domain necessary for homodimerization. The PLC catalytic core domain is a TIM barrel with two highly conserved regions (X and Y) split by a highly degenerate linker sequence.
Jiyao W et al.(2023). "The conserved domain database in 2023.",