APC/CFZR-1 regulates centrosomal ZYG-1 to limit centrosome number.
Aberrant centrosome numbers are associated with human cancers. The levels of centrosome regulators positively correlate with centrosome number. Thus, tight control of centrosome protein levels is critical. In Caenorhabditis elegans, the anaphase-promoting complex/cyclosome and its co-activator FZR-1 (APC/CFZR-1), a ubiquitin ligase, negatively regulates centrosome assembly through SAS-5 degradation. In this study, we report the C. elegans ZYG-1 (Plk4 in humans) as a potential substrate of APC/CFZR-1. Inhibiting APC/CFZR-1 or mutating a ZYG-1 destruction (D)-box leads to elevated ZYG-1 levels at centrosomes, restoring bipolar spindles and embryonic viability to zyg-1 mutants, suggesting that APC/CFZR-1 influences centrosomal ZYG-1 via the D-box motif. We also show the Slimb/βTrCP-binding (SB) motif is critical for ZYG-1 degradation, substantiating a conserved mechanism by which ZYG-1/Plk4 stability is regulated by the SKP1-CUL1-F-box (Slimb/βTrCP)-protein complex (SCFSlimb/βTrCP)-dependent proteolysis via the conserved SB motif in C. elegans. Furthermore, we show that co-mutating ZYG-1 SB and D-box motifs stabilizes ZYG-1 in an additive manner, suggesting that the APC/CFZR-1 and SCFSlimb/βTrCP ubiquitin ligases function cooperatively for timely ZYG-1 destruction in C. elegans embryos where ZYG-1 activity remains at threshold level to ensure normal centrosome number.
['Medley|Jeffrey C|JC|0000-0002-0965-4233', 'DiPanni|Joseph R|JR|0000-0003-3082-1881', 'Schira|Luke|L|0000-0001-6779-0279', 'Shaffou|Blake M|BM|0000-0003-3884-7138', 'Sebou|Brandon M|BM|0000-0003-0808-7174', 'Song|Mi Hye|MH|0000-0001-8326-6602']
D064173:Anaphase-Promoting Complex-Cyclosome D000818:Animals D017173:Caenorhabditis elegans D029742:Caenorhabditis elegans Proteins D018797:Cell Cycle Proteins D018385:Centrosome D006801:Humans D011494:Protein Kinases D017346:Protein Serine-Threonine Kinases D044844:beta-Transducin Repeat-Containing Proteins
Centrosome ZYG-1 FZR-1 C. elegans Proteolysis APC/C