Fig. 2.

Ub-ProT protects substrate-attached ubiquitin chains in vitro. a Ub-ProT assay of tetraubiquitin-fused Sic1. M1-linked tetraubiquitin-fused T7-Sic1, cleaved tetraubiquitin, and ubiquitin monomer are indicated. A ubiquitin mutant (I44A in each ubiquitin moiety, resulting in a defect in TR-TUBE binding) was used as a control. Unanchored M1 chains were used as ubiquitin markers. b Ub-ProT assay of ubiquitylated proteins. Self-ubiquitylated GST-Cdc34 (Ubn-Cdc34, left), self-ubiquitylated GST-Rsp5 (Ubn-Rsp5, middle), and self-ubiquitylated MBP-Parkin (Ub-Parkin, right) were subjected to Ub-ProT. Free ubiquitin chains were used as markers