Molecular and functional characterization of a novel RING-H2 finger protein, ANAPC11, the anaphase-promoting complex subunit 11

ANAPC11, anaphase-promoting complex (APC) subunit 11, is highly conserved among eukaryotic species and encodes a RING-H2 finger domain. In coherent with its family members, it binds with a Cullin structure, the APC2, to form the minimal catalytic core in the E3 ligase. Through ubiquitination and targeted proteasomal degradation of mitotic cyclins, regulates important events in mitosis.; We here demonstrate that ANAPC11 performs functional role in tumour pathogenesis and developmental regulation. Initially isolated during a large-scale partial sequencing of a human liver cancer cDNA library with higher abundance then the normal counterpart, it is also shown to be up-regulated in cancer patient. Coherently, ANAPC11 is shown to be differentially expressed in different cancer cell lines and its expression is identified to be up-regulated in leukaemia and lung cancer cell lines compared to the corresponding normal tissue expression in the Multiple Tissue Expression Array RNA dot blot study. It is mapped to human chromosome 17q25, a locus often deleted in several human malignancies.; ANAPC11 is found to be differentially localized, with accumulation in the perinuclear region and cytoplasm during G1 and shuttled into the nucleus in G2/M phase.; With dominant expression level in heart and skeletal muscle, its role in regulating rat heart development is investigated. Up-surged expression level of this gene in day 7 post-natal rat heart and differentiated C2C12 myoblast cell line tentatively suggest its involvement in cardiomyocyte differentiation during hyperplastic to hypertrophic shift.; Overexpression of ANAPC11 shows early S phase shift by flow cytometry and increased DNA synthesis by BrdU incorporation assay and results in polyploidization of C2C12 and H9C2 cells in different differentiation stages. It is found to have mild cardioprotective effect against reactive oxygen species induced cardiotoxicity. Therefore, implicative role of this involvement of induced endoreplication by overexpressed ANAPC11 in tumourigenesis and development remains elusive.; Moreover, a modified mammalian two hybrid system reporter generated to facilitate downstream studies of protein interaction pairs would be discussed.