d, GST pull down (i) and immunopurification assays (ii) of CPAP's CC5 domain demonstrate its sufficiency in mediating CPAP-CDC protein interactions. The CC5 fragment is expressed as a GFP fusion protein in HeLa cells and immunopurified using anti-GFP antibodies. HeLa extracts were used as input controls. CAP350 does not co-purify with CPAP. Both Cap350 and ODF2 are not pulled down by CPAP's CC5 domain. 