p23_like domain of NUD (nuclear distribution) C and similar proteins. Aspergillus nidulas (An) NUDC is needed for nuclear movement. AnNUDC is localized at the hyphal cortex, and binds NUDF at spindle pole bodies (SPBs) and in the cytoplasm at different stages in the cell cycle. At the SPBs it is part of the dynein molecular motor/NUDF complex that regulates microtubule dynamics. Mammalian(m) NUDC associates both with the dynein complex and also with an anti-inflammatory enzyme, platelet activating factor acetylhydrolase I, PAF-AH(I) complex, through binding mNUDF, the regulatory beta subunit of PAF-AH(I). mNUDC is important for cell proliferation both in normal and tumor tissues. Its expression is elevated in various cell types undergoing mitosis or stimulated to proliferate, with high expression levels observed in leukemic cells and tumors. For a leukemic cell line, human NUDC was shown to activate the thrombopoietin (TPO) receptor (Mpl) by binding to its extracellular domain, and promoting cell proliferation and differentiation. This group also includes the human broadly immunogenic tumor associated antigen, CML66, which is highly expressed in a variety of solid tumors and in leukemias. In normal tissues high expression of CML66 is limited to testis and heart.