Amyloid Beta Precursor Protein Binding B1 Interacting Protein (APBB1IP)

The deduced 666-amino acid protein contains an N-terminal proline-rich domain, a RAS-associated domain, a PH domain, and a long C-terminal proline-rich domain. Northern blot analysis detected a 2.6-kb transcript in most tissues, with highest expression in thymus, spleen, liver, and peripheral leukocytes. RNA dot blot analysis detected RARP1 preferentially expressed in thymus, spleen, lymph node, bone marrow, and peripheral leukocytes. Western blot analysis showed that endogenous promyeloleukemic cell RARP1 has an apparent molecular mass of 110 kD. Immunostaining of transfected Chinese hamster ovary cells found RARP1 localized to the cytoplasm. Endogenous mouse Rarp1 was found in the cytoplasm of megakaryocytes or their progenitor cells in bone marrow and spleen.