Has a key role in phospholipid biosynthesis. Catalyzes the first step in phosphatidylethanolamine biosynthesis. Phosphorylates ethanolamine, and can also act on choline (in vitro). Has higher activity with ethanolamine. May not significantly contribute to in vivo phosphatidylcholine biosynthesis. Belongs to the choline/ethanolamine kinase family. 2 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.