This family represents a high-affinity plasma-membrane choline transporter in C.elegans which is thought to be rate-limiting for ACh synthesis in cholinergic nerve terminals [1].

1: Reexamining the role of choline transporter-like (Ctlp) proteins in choline transport. Zufferey R, Santiago TC, Brachet V, Ben Mamoun C; Neurochem Res. 2004;29:461-467. PMID:15002745