Arginine methyltransferase that methylates (mono and asymmetric dimethylation) the guanidino nitrogens of arginyl residues present in target proteins. Mediates asymmetric dimethylation of components of the axoneme during flagellum resorption, such as CCDC40/FAP172, CCDC65/FAP250, RSP1, RSP2, RPS5, RSP6, and tektin (PubMed:24152136). Localizes to the flagellum in a punctate pattern along the length of the axoneme. During resorption, localization is enhanced at the flagellar tip, the site of the disassembly of the flagellar axoneme. Phosphorylated during flagellum resorption. Belongs to the class I-like SAM-binding methyltransferase superfamily. Protein arginine N-methyltransferase family.