AbstractYeast Apc11p together with Rbx1 and Roc2/SAG define a new class of RING‐H2 fingers in a superfamily of E3 ubiquitin ligases. The human homolog of Apc11p, ANAPC11 was identified during a large‐scale partial sequencing of a human liver cancer cDNA library and partial characterization was performed. This 514 bp full‐length cDNA has a predicted open reading frame (ORF) encoding 84 amino acids. The ORF codes for ANAPC11, the human anaphase promoting complex subunit 11 (yeast APC11 homolog), which possesses a RING‐H2 finger motif and exhibits sequence similarity to subunits of E3 ubiquitin ligase complexes. In Northern blot hybridization with poly(A) RNA of various human tissues using radio‐labelled ANAPC11 cDNA probe, we found strong signals detected in skeletal muscle and heart; moderate signals detected in brain, kidney, and liver; and detectable but low signals in colon, thymus, spleen, small intestine, placenta, lung, and peripheral blood leukocyte. The ANAPC11 gene is located at the human chromosome 17q25. ANAPC11 is distributed diffusely in the cytoplasm and nucleus with discrete accumulation in granular structures in all the cell lines (AML 12, HepG2, and C2C12) transfected. Expression level of ANAPC11 is found higher in certain types of cancer determined in the RNA dot blot experiment. J. Cell. Biochem. 83: 249–258, 2001. © 2001 Wiley‐Liss, Inc.