Anti-C9orf72-SMCR8 complex subunit antibodies are used for the immunodetection of the protein encoded by the C9orf72 gene. In humans, the canonical protein has a reported length of 481 amino acid residues and a mass of 54.3 kDa. Its subcellular localization is in the nucleus, cytoplasmic vesicles, lysosomes, cytoplasm, and is secreted. Alternative splicing is reported to yield 2 different isoforms for this protein. It is a known component of the C9orf72-SMCR8 complex, a complex that has guanine nucleotide exchange factor (GEF) activity and regulates autophagy. The gene encoding this protein is implicated in Frontotemporal dementia and/or amyotrophic lateral sclerosis. Other names for this target antigen include guanine nucleotide exchange C9orf72, protein C9orf72, and guanine nucleotide exchange factor C9orf72. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.