ENTPD6

ENTPD6 Full Name

ectonucleoside triphosphate diphosphohydrolase 6 (putative)

ENTPD6 Introduction

ENTPD6 is a Golgi-resident ectonucleoside triphosphate diphosphohydrolase that hydrolyzes nucleoside tri- and diphosphates but, unlike the prototypical ENTPD1 (CD39), prefers nucleoside diphosphates as substrates. It was originally cloned as a CD39-like protein and is the product of a single gene located on human chromosome 20pter–p12, with broad but uneven tissue distribution. The protein spans the Golgi membrane twice, exposing its catalytic domain to the lumen, where it modulates the luminal concentrations of UDP, GDP, and related nucleotides that feed glycosylation and protein-trafficking reactions.

Figure 1. ENTPD6 gene: ectonucleoside triphosphate diphosphohydrolase 6.

Regulation of Luminal Nucleotide Pools in the Secretory Pathway
Within the Golgi cisternae, ENTPD6 hydrolyzes UDP and GDP released during sugar-nucleotide turnover, thereby shaping the substrate availability for glycosyltransferases and for GTPases such as Rab family members that operate on the cytosolic face. By lowering the concentration of diphosphate products in the lumen, the enzyme also buffers against osmotic stress and supports the efficient flux of nascent glycoproteins. Biochemical studies show that ENTPD6 operates at an acidic pH optimum and is sensitive to calcium, features consistent with its residence in late- and trans-Golgi compartments where it cooperates with other nucleotide-sugar transporters.

Cancer Metabolism and Biomarker Potential
Although ENTPD6 is widely expressed, several expression-profiling studies have noted its upregulation in colorectal carcinoma and certain B-cell lymphomas, where the resulting alterations of luminal nucleotide pools may favor the secretion of glycoproteins that remodel the tumor microenvironment. Its more restricted substrate preference distinguishes it pharmacologically from CD39, an emerging immuno-oncology target, and small molecules that selectively inhibit ENTPD6 are being explored as tools to perturb cancer-associated glycosylation. Loss-of-function variants, while rare, have been reported in patients with unexplained glycosylation defects, suggesting a possible role in congenital disorders of glycosylation.

Alternate Names for ENTPD6

ENTPD6; ectonucleoside triphosphate diphosphohydrolase 6 (putative); CD39L2, IL6ST2, interleukin 6 signal transducer 2; ectonucleoside triphosphate diphosphohydrolase 6; dJ738P15.3; NTPDase 6; CD39-like 2; CD39 antigen-like 2; HCV-E2 binding protein 1; interleukin 6 signal transducer-2