The deduced 326-amino acid protein has a calculated molecular mass of 35.9 kD. PIM3 shares 95% amino acid identity with rodent Pim3 and 57.1% and 44.0% amino acid identity with human PIM1 and PIM2 , respectively.
Northern blot analysis detected a 2.4-kb transcript in heart, skeletal muscle, brain, spleen, kidney, placenta, lung, and peripheral blood leukocytes. Expression was not detected in colon, thymus, liver, and small intestine. Immunohistochemical analysis showed no expression of PIM3 in normal liver, but it localized diffusely in large regenerative nodules and adenomatous hyperplasia, lesions with precancerous potential, adjacent to hepatocellar carcinoma areas. PIM3 was expressed in all hepatoma cell lines examined.