Component of the nuclear body, also known as nuclear domain 10, PML oncogenic domain, and KR body (PubMed:8910577). May be involved in the pathogenesis of acute promyelocytic leukemia and viral infection (PubMed:8910577). May play a role in chromatin-mediated regulation of gene expression although it does not bind to histone H3 tails (PubMed:24267382). Interacts with PIN1. Localized to nuclear structures termed LANDS, for LYSp100-associated nuclear domains. LANDS are globular, electron-dense structures most often found in the nucleoplasm, but also found at the nuclear membrane and in the cytoplasm, suggesting that these structures may traffic between the cytoplasm and the nucleus (PubMed:8695863). Also colocalizes with PML in a subset of PML nuclear bodies (PubMed:8910577). High levels in spleen and peripheral blood leukocytes, much lower levels in tonsils, thymus, prostate, ovary, small intestine, and colon (PubMed:8695863, PubMed:8910577.) Very low levels in heart, brain, placenta, lung, liver, skeletal muscle, kidney, and pancreas (PubMed:8910577). Not detected in brain, liver and muscle (PubMed:8695863). By gamma-interferon. Phosphorylation at Thr-726 promotes binding of PIN1 and subsequent isomerization of Pro-727. This antigen is recognized by autoantibodies from patients with primary biliary cirrhosis.