1-phosphatidylinositol-4,5-bisphosphate phosphodiesterase delta 4 (phosphoinositide phospholipase C delta-4, PLC-delta-4, phospholipase C-delta-4, hPLCD4, PLCD4)
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Function
- hydrolyzes the phosphatidylinositol 4,5-bisphosphate (PIP2) to generate 2 second messenger molecules diacylglycerol (DAG) & inositol 1,4,5-trisphosphate (IP3)
- required for acrosome reaction in sperm during fertilization, probably via intracellular Ca+2 mobilization in the zona pellucida-induced acrosome reaction
- role in cell growth (putative)
- modulates the liver regeneration in cooperation with nuclear PKC
- overexpression upregulates the Erk signaling pathway & proliferation
- interacts with GRIP1 (putative)
1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate + H2O
<-->
1D-myo-inositol 1,4,5-trisphosphate + diacylglycerol
Cofactor:
- binds 3 Ca+2 per subunit
- 2 Ca+2 are bound to the C2 domain (putative)
Structure
- PDZ-binding motif mediates the interaction with GRIP1
- C2 domain mediates pre-localization to the membrane prior to Ca+2 import & non-selective Ca(2+)-mediated targetingto various cellular membranes
- PH domain is not a critical determinant of membrane localization
- contains 1 C2 domain
- contains 3 EF-hand domains
- contains 1 PH domain
- contains 1 PI-PLC X-box domain
- contains 1 PI-PLC Y-box domain
Compartment
- membrane, peripheral membrane, nucleus, cytoplasm
- endoplasmic reticulum
- localizes primarily to intracellular membranes mostly to the endoplasmic reticulum
Alternative splicing
named isoforms=2
Expression
- highly expressed in skeletal muscle & kidney tissues, & at moderate level in intestinal tissue
- expressed incorneal epithelial cells