Dual methyltransferase. It catalyzes N-terminal methylation of target proteins via its C-terminus. It catalyzes dimethylation on lysine residues of target proteins via its N-terminus. 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 Belongs to the methyltransferase superfamily.