Plays a role in processing of mitochondrial RNA precursors and in stabilization of a subset of mature mitochondrial RNA species, such as MT-CO1, MT-CO2, MT-CYB, MT-CO3, MT-ND3, MT-ND5 and MT-ATP8/6. May play a role in cell cycle progression. Expression detected in spleen, testis, colon, heart, smooth muscle, kidney, brain, lung, liver, brown and white adipose tissue with highest expression in testis, heart, smooth muscle and brown adipose tissue. Belongs to the FAST kinase family. Truncated C-terminus.