Enables mitochondrion targeting sequence binding activity. Involved in protein targeting to mitochondrion; response to 3,3',5-triiodo-L-thyronine; and response to muscle activity. Located in mitochondrial outer membrane. Biomarker of muscular atrophy. Orthologous to human TOMM20 (translocase of outer mitochondrial membrane 20). [provided by Alliance of Genome Resources, Apr 2022]