Editing Anaphase-promoting complex (section)

===CDC23, CDC16, CDC27===

CDC23, another TPR subunit interacts with SWM1, binding to the D-box of CLB2. Based upon hybrid assays in vivo and co-immunoprecipitation in vitro, it is suggested that Cdc16p, Cdc23p and Cdc27p (analogs in Sacchyromyces cerevisiae) interact and form a macromolecular complex. Their common theme of TPR is suggested to mediate these interactions.<ref>{{cite journal | vauthors = Lamb JR, Michaud WA, Sikorski RS, Hieter PA | title = Cdc16p, Cdc23p and Cdc27p form a complex essential for mitosis | journal = The EMBO Journal | volume = 13 | issue = 18 | pages = 4321–8 | date = September 1994 | pmid = 7925276 | doi = 10.1002/j.1460-2075.1994.tb06752.x | pmc = 395359 }}</ref>  As for Cdc27 and Cdc16 in drosophila, their functions have been tested via [[RNA interference]] (RNAi).<ref>{{cite journal | vauthors = Huang JY, Raff JW | title = The dynamic localisation of the Drosophila APC/C: evidence for the existence of multiple complexes that perform distinct functions and are differentially localised | journal = Journal of Cell Science | volume = 115 | issue = Pt 14 | pages = 2847–56 | date = July 2002 | doi = 10.1242/jcs.115.14.2847 | pmid = 12082146 | url = http://jcs.biologists.org/cgi/pmidlookup?view=long&pmid=12082146 | url-access = subscription }}</ref> Results suggest that they may mediate activity of the entire complex via different mechanisms at different sites. In further drosophila studies, Cdk16 and cdk23 appear to be activated via phosphorylation by Polo-like kinase 1 (Plk1) and its fission yeast counterpart, appear to bind particularly to Cdc23.<ref>{{cite journal | vauthors = Deak P, Donaldson M, Glover DM | title = Mutations in mákos, a Drosophila gene encoding the Cdc27 subunit of the anaphase promoting complex, enhance centrosomal defects in polo and are suppressed by mutations in twins/aar, which encodes a regulatory subunit of PP2A | journal = Journal of Cell Science | volume = 116 | issue = Pt 20 | pages = 4147–58 | date = October 2003 | pmid = 12953067 | doi = 10.1242/jcs.00722 | doi-access = free }}</ref>

The complex is understood to be regulated by activators CDC20 and Cdh1 during mitosis. Their role in degradation for cyclin B is demonstrated by a screen of Saccharomyces cerevisiae mutants defective for cyclin B degradation, which were found to have mutations in CDC16 and CDC23 genes. Mutants for CDC27, CDC23 and CDC 27 all resulted in a cell-cycle arrest at metaphase.<ref>{{cite journal | vauthors = Hartwell LH, Smith D | title = Altered fidelity of mitotic chromosome transmission in cell cycle mutants of S. cerevisiae | journal = Genetics | volume = 110 | issue = 3 | pages = 381–95 | date = July 1985 | doi = 10.1093/genetics/110.3.381 | pmid = 3894160 | pmc = 1202570 }}</ref>