Proapoptotic Caspase Adaptor Protein associates with immunoglobulin M (IgM) heavy and light chains and promotes IgM assembly and secretion. May exert its effect by acting as a molecular chaperone or as an oxidoreductase as it displays a low level of oxidoreductase activity By similarity. Isoform 2 may be involved in regulation of apoptosis.
Isoform 1: Endoplasmic reticulum
Isoform 2: Cytoplasm. Note: Diffuse granular localization in the cytoplasm surrounding the nucleus.