MASS-SPECTROMETRIC ANALYSIS OF THE ANAPHASE-PROMOTING COMPLEX FROM YEAST - IDENTIFICATION OF A SUBUNIT RELATED TO CULLINS

Entry into anaphase and exit from mitosis depend on a ubiquitin-protei n ligase complex called the anaphase-promoting complex (APC) or cyclos ome. At least 12 different subunits were detected in the purified part icle from budding yeast, including the previously identified proteins Apc1p, Cdc16p, Cdc23p, Cdc26p, and Cdc27p, Five additional subunits pu rified in low nanogram amounts were identified by tandem mass spectrom etric sequencing, Apc2p, Apc5p, and the RING-finger protein Apc11p are conserved from yeast to humans, Apc2p is similar to the cullin Cdc53p , which is a subunit of the ubiquitin-protein ligase complex SCFCdc4 r equired for the initiation of DNA replication.