ENPP2
Domain
The nuclease-like domain is most probably catalytically inactive as residues that are essential for catalysis in the DNA/RNA non-specific endonucleases are not conserved. However, it is required for the stability of the protein and the catalytic activity born by the Phosphodiesterase domain.
Function
Secreted lysophospholipase D that hydrolyzes lysophospholipids to produce the signaling molecule lysophosphatidic acid (LPA) in extracellular fluids (PubMed:12354767, PubMed:14500380, PubMed:15769751, PubMed:26371182, PubMed:27754931). Its major substrate is lysophosphatidylcholine (PubMed:12176993, PubMed:14500380, PubMed:27754931). Can also act on sphingosylphosphorylcholine producing sphingosine-1-phosphate, a modulator of cell motility (PubMed:14500380). Can hydrolyze, in vitro, bis-pNPP, to some extent pNP-TMP, and barely ATP (PubMed:12176993, PubMed:15769751). Involved in several motility-related processes such as angiogenesis and neurite outgrowth. Acts as an angiogenic factor by stimulating migration of smooth muscle cells and microtubule formation (PubMed:11559573). Stimulates migration of melanoma cells, probably via a pertussis toxin-sensitive G protein (PubMed:1733949). May have a role in induction of parturition (PubMed:12176993). Possible involvement in cell proliferation and adipose tissue development (Probable). Required for LPA production in activated platelets, cleaves the sn-1 lysophospholipids to generate sn-1 lysophosphatidic acids containing predominantly 18:2 and 20:4 fatty acids (PubMed:21393252). Shows a preference for the sn-1 to the sn-2 isomer of 1-O-alkyl-sn-glycero-3-phosphocholine (lyso-PAF) (PubMed:21393252).
Post-translational modifications
N-glycosylation, but not furin-cleavage, plays a critical role on secretion and on lysoPLD activity.
The interdomain disulfide bond between Cys-414 and Cys-806 is essential for catalytic activity.
Sequence Similarities
Belongs to the nucleotide pyrophosphatase/phosphodiesterase family.
Tissue Specificity
Detected in blood plasma (at protein level) (PubMed:12176993, PubMed:26371182). Predominantly expressed in brain, placenta, ovary, and small intestine. Expressed in a number of carcinomas such as hepatocellular and prostate carcinoma, neuroblastoma and non-small-cell lung cancer. Expressed in body fluids such as plasma, cerebral spinal fluid (CSF), saliva, follicular and amniotic fluids. Not detected in leukocytes. Isoform 1 is more highly expressed in peripheral tissues than in the central nervous system (CNS). Adipocytes only express isoform 1. Isoform 3 is more highly expressed in the brain than in peripheral tissues.
Cellular localization
- Secreted
Alternative names
ATX, PDNP2, ENPP2, Autotaxin, Ectonucleotide pyrophosphatase/phosphodiesterase family member 2, Extracellular lysophospholipase D, E-NPP 2, LysoPLD