Ectonucleoside Triphosphate Diphosphohydrolase 2 (ENTPD2)

ENTPD2 is the type 2 enzyme of the ecto-nucleoside triphosphate diphosphohydrolase family. E-NTPDases are a family of ecto-nucleosidases that hydrolyze 5'-triphosphates. This ecto-ATPase is an integral membrane protein. Alternative splicing of this gene results in multiple transcript variants. Overexpression of ENTPD2, an ectoenzyme that converts ATP to ADP, caused ectopic eye-like structures, with occasional complete duplication of the eye, and increased expression of Pax6, Rx1, and Six3 . In contrast, downregulation of endogenous ENTPD2 decreased Rx1 and Pax6 expression.This role for transient purine-mediated signaling in eye development may be widely conserved, because alterations to the ENTPD2 locus on human chromosome 9 cause severe head and eye defects, including microphthalmia.