Dual methyltransferase that catalyzes methylation of elongation factor 1-alpha (EEF1A1 and EEF1A2) at two different positions, and is therefore involved in the regulation of mRNA translation (By similarity). Via its C-terminus, methylates EEF1A1 and EEF1A2 at the N-terminal residue 'Gly-2' (By similarity). Via its N-terminus dimethylates EEF1A1 and EEF1A2 at residue 'Lys-55' (By similarity). Has no activity towards core histones H2A, H2B, H3 and H4 (By similarity). Negatively regulates cell proliferation at G1/S transition via transcriptional suppression of cell cycle regulatory genes such as CDK4 and CDK6 (By similarity). L-lysyl-[protein] + S-adenosyl-L-methionine = H(+) + N(6)-methyl-L-lysyl-[protein] + S-adenosyl-L-homocysteine N(6)-methyl-L-lysyl-[protein] + S-adenosyl-L-methionine = H(+) + N(6),N(6)-dimethyl-L-lysyl-[protein] + S-adenosyl-L-homocysteine N-terminal glycyl-L-lysyl-L-glutamyl-[protein] + 3 S-adenosyl-L-methionine = 3 H(+) + N-terminal N,N,N-trimethyl-glycyl-L-lysyl-L-glutamyl-[protein] + 3 S-adenosyl-L-homocysteine Forms a tripartite complex containing GAB1, METTL13 and SPRY2 (By similarity). Within the complex interacts with GAB1 and SPRY2 (By similarity). Expressed in the inner ear (at protein level) (PubMed:29408807). Expression is detected in the cochlear duct, spiral limbus region, efferent and afferent nerves, and in spiral ganglion neurons (at protein level) (PubMed:29408807). Belongs to the methyltransferase superfamily.