cl20473

Anaphase-promoting complex subunit 5; Apc5 is a subunit of the anaphase-promoting complex/cyclosome (APC/C) which is a multi-subunit ubiquitin ligase that mediates the proteolysis of cell cycle proteins in mitosis and G1. Apc5, although it does not harbour a classical RNA binding domain, Apc5 binds the poly(A) binding protein (PABP), which directly binds the internal ribosome entry site (IRES) of growth factor 2 mRNA. PABP was found to enhance IRES-mediated translation, whereas Apc5 over-expression counteracted this effect. In addition to its association with the APC/C complex, Apc5 binds much heavier complexes and co-sediments with the ribosomal fraction. The N-terminus of Afi1 serves to stabilize the union between Apc4 and Apc5, both of which lie towards the bottom-front of the APC. This region of the Apc5 member proteins carries a TPR-like motif.