Phosphatidylinositol-specific phospholipase C, X domain (IPR000909)

Short name: PLipase_C_PInositol-sp_X_dom

Overlapping homologous superfamilies

Domain relationships



Phosphatidylinositol-specific phospholipase C, a eukaryotic intracellular enzyme, plays an important role in signal transduction processes [PMID: 1849017]. It catalyzes the hydrolysis of 1-phosphatidyl-D-myo-inositol-3,4,5-triphosphate into the second messenger molecules diacylglycerol and inositol-1,4,5-triphosphate. This catalytic process is tightly regulated by reversible phosphorylation and binding of regulatory proteins [PMID: 1419362, PMID: 1319994, PMID: 1335185]. In mammals, there are at least 6 different isoforms of PI-PLC, they differ in their domain structure, their regulation, and their tissue distribution. Lower eukaryotes also possess multiple isoforms of PI-PLC. All eukaryotic PI-PLCs contain two regions of homology, sometimes referred to as the 'X-box' and 'Y-box'. The order of these two regions is always the same (NH2-X-Y-COOH), but the spacing is variable. In most isoforms, the distance between these two regions is only 50-100 residues but in the gamma isoforms one PH domain, two SH2 domains, and one SH3 domain are inserted between the two PLC-specific domains. The two conserved regions have been shown to be important for the catalytic activity. By profile analysis, we could show that sequences with significant similarity to the X-box domain occur also in prokaryotic and trypanosome PI-specific phospholipases C. Apart from this region, the prokaryotic enzymes show no similarity to their eukaryotic counterparts.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE profiles