ENPP7
Function
Choline-specific phosphodiesterase that hydrolyzes sphingomyelin releasing the ceramide and phosphocholine and therefore is involved in sphingomyelin digestion, ceramide formation, and fatty acid (FA) absorption in the gastrointestinal tract (PubMed:12671034, PubMed:12885774, PubMed:15205117, PubMed:16255717, PubMed:28292932). Has also phospholipase C activity and can also cleave phosphocholine from palmitoyl lyso-phosphatidylcholine and platelet-activating factor (PAF) leading to its inactivation (PubMed:12885774, PubMed:16255717). Does not have nucleotide pyrophosphatase activity (PubMed:12885774). May promote cholesterol absorption by affecting the levels of sphingomyelin derived from either diet or endogenous sources, in the intestinal lumen (By similarity).
Post-translational modifications
N-glycosylated; required for activity and transport to the plasma membrane.
Sequence Similarities
Belongs to the nucleotide pyrophosphatase/phosphodiesterase family.
Tissue Specificity
Detected in the colon (at protein level). Expressed in the duodenum, jejunum and liver and at low levels in the ileum. Expression was very low in the esophagus, stomach and colon.
Cellular localization
- Cell membrane
- Single-pass type I membrane protein
- The catalytic domain is released into the extracellular medium when cells are treated with trypsin (PubMed:15205117). Localized at the surface of the microvillar membrane in small intestine enterocytes, and in endosome-like structures situated beneath the microvillar membrane, and in Golgi complex (PubMed:12671034, PubMed:12885774).
Alternative names
UNQ3077/PRO9912, ENPP7, Ectonucleotide pyrophosphatase/phosphodiesterase family member 7, E-NPP 7, NPP-7, Alkaline sphingomyelin phosphodiesterase, Intestinal alkaline sphingomyelinase, Alk-SMase