Timing of APC/C substrate degradation is determined by fzy/fzr specificity of destruction boxes

Amit Zur, Michael Brandeis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

74 Scopus citations


The anaphase promoting complex/cyclosome (APC/C), activated by fzy and fzr, degrades cell cycle proteins that carry RXXL or KEN destruction boxes (d-boxes). APC/C substrates regulate sequential events and must be degraded in the correct order during mitosis and G1. We studied how d-boxes determine APC/Cfzy/APC/Cfzr specificity and degradation timing. Cyclin B1 has an RXXL box and is degraded by both APC/Cfzy and APC/Cfzr; fzy has a KEN box and is degraded by APC/Cfzr only. We characterized the degradation of substrates with swapped d-boxes. Cyclin B1 with KEN was degraded by APC/Cfzr only. Fzy with RXXL could be degraded by APC/Cfzy and APC/Cfzr. Interestingly, APC/Cfzy- but not APC/Cfzr-specific degradation is highly dependent on the location of RXXL. We studied degradation of tagged substrates in real time and observed that APC/Cfzr is activated in early G1. These observations demonstrate how d-box specificities of APC/Cfzy and APC/Cfzr, and the successive activation of APC/C by fzy and fzr, establish the temporal degradation pattern. Our observations can explain further why some endogenous RXXL substrates are degraded by APC/Cfzy, while others are restricted to APC/Cfzr.

Original languageAmerican English
Pages (from-to)4500-4510
Number of pages11
JournalEMBO Journal
Issue number17
StatePublished - 2 Sep 2002


  • APC
  • C
  • Cyclosome
  • Destruction box
  • Fizzy
  • Fizzy-related


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