The function of the protein encoded by MACROD2 is poorly understood. It contains a macro domain that is evolutionarily conserved and expressed in fetal and adult human brain.20,21 Macro domains bind ADP-ribose, suggesting a role in ADP-ribosylation, a post-translational modification involved in many processes including DNA repair, transcriptional activation and repression, and telomere and chromatin biology.22 Nested in intron 3 of MACROD2, FLRT3 encodes fibronectin leucine rich transmembrane protein 3.23 The gene is expressed in various tissues, including brain, and is well conserved across species.24 The protein it encodes modulates homotypic cell adhesion and promotes fibroblast growth factor signaling,24 which is potentially involved in angiogenesis and neurogenesis.25 In animal experiments, FLRT3 was shown to promote neurite outgrowth after axonal injury.26,27
