A novel gene (GenBank accession No. AF113208) named KCTD10 (potassium channel tetramerisation domain-containing 10) was cloned from our 5300 EST database of human aorta cDNA library. Computational analysis showed that KCTD10 cDNA is 2,638 bp long, encoding 313 amino acids with a proliferating cell nuclear antigen binding motif, mapped to chromosome 12q24.11 with 7 exons, ubiquitously expressed in all 12 tested normal tissues and 7 of 8 tested tumor cell lines from MTN membranes by Northern blot. Nuclear localization of KCTD10 was observed in A549 cells. Yeast two-hybrid analysis and immunoprecipitation assay showed that KCTD10 can interact with PCNA. In A549 cells, KCTD10 down-regulation could inhibit cell proliferation, but its over-expression could not influence cell proliferation. The results suggest that KCTD10 may be associated with DNA synthesis and cell proliferation.