Component of the elongator complex which is required for multiple tRNA modifications, including mcm5U (5-methoxycarbonylmethyl uridine), mcm5s2U (5-methoxycarbonylmethyl-2-thiouridine), and ncm5U (5-carbamoylmethyl uridine) (PubMed:29332244). The elongator complex catalyzes the formation of carboxymethyluridine in the wobble base at position 34 in tRNAs (PubMed:29332244). tRNA modification; 5-methoxycarbonylmethyl-2-thiouridine-tRNA biosynthesis. Component of the elongator complex which consists of ELP1, ELP2, ELP3, ELP4, ELP5 and ELP6 (PubMed:11714725, PubMed:22854966). Widely expressed. The disease is caused by variants affecting the gene represented in this entry. A disease-causing mutation is located in intron 9 of ELP4. The mutation does not alter normal ELP4 expression and function, but disrupts a long-range cis-regulatory element of PAX6 expression, known as SIMO. SIMO is contained within ELP4 intron 9 and located 150 kb downstream of PAX6. Belongs to the ELP4 family. The elongator complex was originally thought to play a role in transcription elongation. However, it is no longer thought to play a direct role in this process and its primary function is thought to be in tRNA modification.