Peptidylprolyl Isomerase A Like Protein 4A (PPIAL4A)

By positional cloning for genes located within a region of chromosome 1 amplified in several cancers, Meza-Zepeda et al. (2002) identified COAS2, and they cloned COAS2 from an osteosarcoma cell line cDNA library. The deduced 164-amino acid protein shares 84% amino acid identity with cyclophilin A (PPIA), including complete conservation of critical residues in the active site and in the cis-proline binding pocket. Northern blot analysis detected COAS2 expression in most normal tissues tested, with highest levels in brain and lowest levels in skeletal muscle. While the COAS2 gene was amplified in all of the liposarcomas studied, elevated expression was detected only in pleomorphic and undifferentiated liposarcomas. COAS2 was also highly expressed in several osteosarcomas and breast cancer cell lines.