Alternative titles; symbols
HGNC Approved Gene Symbol: ETNK1
Cytogenetic location: 12p12.1 Genomic coordinates (GRCh38): 12:22,625,171-22,690,665 (from NCBI)
Ethanolamine kinase (ATP:ethanolamine O-phosphotransferase; EC 2.7.1.82) catalyzes the first step in phosphatidylethanolamine (PtdEtn) biosynthesis via the CDP-Etn pathway (Lykidis et al., 2001).
By searching for sequences similar to the Drosophila ethanolamine kinase (eas) gene, followed by RT-PCR of liver RNA, Lykidis et al. (2001) cloned human ETNK1, which they called EKI1. The deduced 452-amino acid protein has a calculated molecular mass of 49.7 kD. EKI1 contains a region rich in hydrophobic residues and a putative transmembrane helix. In transfected cells, however, EKI1 associated with the cytosolic fraction rather than the membrane fraction. Northern blot analysis detected a 2.2-kb EKI1 transcript in all tissues examined and an additional 1.7-kb EKI1 transcript in testis.
Lykidis et al. (2001) found that overexpression of human EKI1 in COS-7 cells increased incorporation of radiolabeled ethanolamine into PtdEtn. Accelerating the CDP-Etn pathway did not elevate cellular PtdEtn levels, since excess PtdEtn was degraded. EKI1 had negligible choline kinase activity in vitro, and overexpression did not influence phosphatidylcholine biosynthesis. Acceleration of the CDP-Etn pathway did not change the rate of PtdEtn formation via decarboxylation of phosphatidylserine.
Zafarana et al. (2002) identified the DADR (609860), SOX5 (604975), and ETNK1 genes within a region of chromosome 12p amplified in testicular seminomas (273300). Although all 3 genes were amplified to the same level in seminomas with the amplification, only DADR expression was significantly upregulated.
Lykidis et al. (2001) determined that the ETNK1 gene contains 8 exons and spans about 60.5 kb.
By genomic sequence analysis, Lykidis et al. (2001) mapped the ETNK1 gene to chromosome 12 in both human and mouse. Zafarana et al. (2002) mapped the ETNK1 gene to chromosome 12p12.1-p11.2 by sequence analysis.
Lykidis, A., Wang, J., Karim, M. A., Jackowski, S. Overexpression of a mammalian ethanolamine-specific kinase accelerates the CDP-ethanolamine pathway. J. Biol. Chem. 276: 2174-2179, 2001. [PubMed: 11044454] [Full Text: https://doi.org/10.1074/jbc.M008794200]
Zafarana, G., Gillis, A. J. M., van Gurp, R. J. H. L. M., Olsson, P. G., Elstrodt, F., Stoop, H., Millan, J. L., Oosterhuis, J. W., Looijenga, L. H. J. Coamplification of DAD-R, SOX5, and EKI1 in human testicular seminomas, with specific overexpression of DAD-R, correlates with reduced levels of apoptosis and earlier clinical manifestation. Cancer Res. 62: 1822-1831, 2002. [PubMed: 11912161]