Plays a role in transcriptional repression of satellite repeats, possibly by regulating H3K36 methylation levels in centromeric regions together with KDM8 (PubMed:24981860). Possibly together with KDM8, is involved in proper mitotic spindle organization and chromosome segregation (PubMed:24981860). Plays a role in regulating alpha-tubulin deacetylation and cytoskeletal microtubule stability, thereby promoting cell migration and TGF-beta-induced epithelial to mesenchymal transition (EMT), potentially through the inhibition of KDM8 (PubMed:28455245). Found in a complex with KDM8 (PubMed:24981860). Interacts (via N-terminus) with KDM8 (via N-terminus)(PubMed:24981860, PubMed:28455245). Colocalizes with trimethylated 'Lys-9' of histone H3 (H3K9me3). Specifically hydroxylated (with R stereochemistry) at C-3 of ARG-141 by KDM8. Postulated to regulate KDM8 histone demethylase activity on di- and trimethylated 'Lys-36' (H3K36me2/me3) of histone H3 (PubMed:24981860). However the demethylase activity of JMJD5 is controversial, as it was later shown to rather act as an endopeptidase that cleaves monomethylated and dimethylated arginine residues of histones H2, H3 and H4. In several studies, JMJD5 was shown not to display any demethylase activity toward methylated H3K36 nor toward other methyllysines in the N-terminal tails of H3 and H4 in vitro (PubMed:28982940).