SCAPER is a 1,399 amino acid protein that contains a C2H2-type zinc finger, a putative transmembrane domain, an ER retrieval signal at the C terminus, four coiled-coil domains, six potential RXL motifs that might confer binding to cyclins and six consensus Cdk phosphorylation sites. SCAPER interacts with, and is phosphorylated in vitro by, the cyclin A/Cdk2 complex at multiple phases of the cell cycle, including S and G2/M. It has been suggested that SCAPER represents a novel cyclin A/Cdk2 regulatory protein that transiently maintains cyclin A in the cytoplasm. The SCAPER protein is predominantly located in the endoplasmic reticulum, with only a small portion detected in the nucleus. Widely expressed, SCAPER demonstrates highest expression in testis. Existing as two alternatively spliced isoforms, the SCAPER gene is conserved in chimpanzee, dog, mouse, rat, chicken and zebrafish, and maps to human chromosome 15q24.3.