Identification of a functional docking site in the Rpn1 LRR domain for the UBA-UBL domain protein Ddi1

摘要: Background: The proteasome is a multi-subunit protein machine that the final destination for cellular proteins have been marked degradation via an ubiquitin (Ub) chain appendage. These ubiquitylated either bind directly to intrinsic ubiqutin receptors Rpn10, Rpn13, or Rpt5, are shuttled by Rad23, Dsk2, Ddi1. latter share Ub association domain (UBA) binding poly-Ub chains and Ub-like-domain (UBL) proteasome. It has proposed shuttling dock on Rpn1, but precise nature of docking site remains poorly defined. Results: To shed light recruitment proteasome, we performed both sitedirected mutagenesis genetic screening identify mutations in Rpn1 disrupt its UBA-UBL proteins. Here demonstrate delivery conjugates Ddi1 (and lesser extent Dsk2) strongly impaired aspartic acid alanine point mutation highly-conserved D517 residue Rpn1. Moreover, Ddi1-dependent substrate, Ufo1, blocked rpn1D517A yeast cells. By contrast, Rad23 not affected rpn1-D517A. Conclusions: studies provide insight into mechanism which recruited enable Ub-dependent ligands. Our suggest different distinct mechanisms.