Cell division cycle protein 16 homolog is a protein that in humans is encoded by the CDC16 gene.

This gene encodes a component protein of the APC complex, which is composed of eight proteins and functions as a protein ubiquitin ligase. The APC complex is a cyclin degradation system that governs exit from mitosis. Each component protein of the APC complex is highly conserved among eukaryotic organisms. This protein and two other APC complex proteins, CDC23 and CDC27, contain a tetratricopeptide repeat (TPR), a protein domain that may be involved in protein-protein interaction. Multiple alternatively spliced variants, encoding the same protein, have been identified. [provided by RefSeq, Jul 2008].
Function: Component of the anaphase promoting complex/cyclosome (APC/C), a cell cycle-regulated E3 ubiquitin ligase that controls progression through mitosis and the G1 phase of the cell cycle. The APC/C complex acts by mediating ubiquitination and subsequent degradation of target proteins: it mainly mediates the formation of 'Lys-11'-linked polyubiquitin chains and, to a lower extent, the formation of 'Lys-48'- and 'Lys-63'-linked polyubiquitin chains.