Structures of APC/C Cdh1 with substrates identify Cdh1 and Apc10 as the D-box co-receptor

摘要: The ubiquitylation of cell-cycle regulatory proteins by the large multimeric anaphase-promoting complex (APC/C) controls sister chromatid segregation and exit from mitosis. Selection APC/C targets is achieved through recognition destruction motifs, predominantly (D)-box KEN (Lys-Glu-Asn)-box. Although this process known to involve a co-activator protein (either Cdc20 or Cdh1) together with core subunits, structural basis for substrate not understood. Here we investigate budding yeast using single-particle electron microscopy determine cryo-electron map in Cdh1 (APC/C(Cdh1)) bound D-box peptide at ∼10 A resolution. We find that combined catalytic substrate-recognition module located within central cavity assembled Cdh1, Apc10--a subunit previously implicated recognition--and cullin domain Apc2. Apc10, identified difference maps, create co-receptor following repositioning towards Apc10. Using NMR spectroscopy demonstrate specific D-box-Apc10 interactions, consistent role Apc10 directly contributing APC/C(Cdh1) complex. Our results rationalize contribution both subunits provide framework understanding mechanisms catalysis APC/C.