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

• Published in: The EMBO journal Vol. 21; no. 17; pp. 4500 - 4510
• Main Authors: Zur, Amit, Brandeis, Michael
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 02.09.2002; Blackwell Publishing Ltd; Oxford University Press
• Subjects: 3T3 Cells - metabolism; Amino Acid Motifs; Amino Acid Sequence; Anaphase-Promoting Complex-Cyclosome; Animals; Antigens, CD; APC; Cadherins; Cdc20 Proteins; Cdh1 Proteins; Cell Cycle Proteins - metabolism; Cyclin B - chemistry; Cyclin B - metabolism; Cyclin B1; cyclosome; Degradation; destruction box; fizzy; fizzy-related; G1 Phase; Humans; Ligases - metabolism; Macromolecular Substances; Mice; Molecular Sequence Data; Proteins - chemistry; Proteins - physiology; Recombinant Fusion Proteins - metabolism; Saccharomyces cerevisiae Proteins - chemistry; Saccharomyces cerevisiae Proteins - physiology; Substrate Specificity; Substrates; Time Factors; Ubiquitin - metabolism; Ubiquitin-Protein Ligase Complexes
• ISSN: 0261-4189; 1460-2075; 1460-2075
• DOI: 10.1093/emboj/cdf452

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.