Histone methyltransferase specifically trimethylating 'Lys-36' of histone H3 forming H3K36me3 (By similarity). Also monomethylates 'Lys-9' of histone H3 (H3K9me1) in vitro (PubMed:22939622). The physiological significance of the H3K9me1 activity is unclear (Probable) (PubMed:22939622). L-lysyl(36)-[histone H3] + 3 S-adenosyl-L-methionine = 3 H(+) + N(6),N(6),N(6)-trimethyl-L-lysyl(36)-[histone H3] + 3 S-adenosyl-L-homocysteine L-lysyl(9)-[histone H3] + S-adenosyl-L-methionine = H(+) + N(6)-methyl-L-lysyl(9)-[histone H3] + S-adenosyl-L-homocysteine The relevance of tight junction localization is however unclear. Methylated at Gln-1218 by N6AMT1. Belongs to the class V-like SAM-binding methyltransferase superfamily. Histone-lysine methyltransferase family. SET2 subfamily. Truncated N-terminus. Truncated N-terminus.