Cross-species divergence of the major recognition pathways of ubiquitylated substrates for ubiquitin/26S proteasome-mediated proteolysis

摘要: The recognition of ubiquitylated substrates is an essential element ubiquitin/26S proteasome-mediated proteolysis (UPP), which mediated directly by the proteasome subunit RPN10 and/or RPN13, or indirectly ubiquitin receptors containing ubiquitin-like and ubiquitin-associated domains. By pull-down mutagenesis assays, we detected cross-species divergence major pathways. plays a role in direct Arabidopsis yeast based on strong affinity for long K48-linked chains. In contrast, both RPN13 homologs play roles humans. For indirect recognition, RAD23 DSK2 (except human homolog) are receptors. homolog targeted to 26S homologs. comparison, uses UIM1 UIM3 bind RAD23, respectively. Yeast UIM LRR RPN1. Overall, multiple subunits responsible single subunit, RPN10, critical pathways Arabidopsis. agreement with these results, accumulation severe pleiotropic phenotypes vegetative reproductive growth associated loss function T-DNA insertion mutant. This implies that targeting regulators involved affected. These results support mechanistic functional UPP.