Figure 2: OPTN-UBAN domain is critical for linear ubiquitin binding. | Nature Communications

Figure 2: OPTN-UBAN domain is critical for linear ubiquitin binding.

From: Linear ubiquitination is involved in the pathogenesis of optineurin-associated amyotrophic lateral sclerosis

Figure 2

(a) The E478G mutation abrogated linear ubiquitin binding. In vitro MBP pull-down experiments using linear (M1)-, K48- or K63-linked tetraubiquitins and MBP-fused lacZ, OPTN-WT, E478G, Q398X and NEMO-WT were performed, and the bound ubiquitin chain was detected by immunoblotting. (b) Kinetic analyses of OPTN and linear ubiquitin. Linear tetraubiquitin was immobilized and various concentrations of OPTN-WT or E478G were tested. Grey lines, a global fit to a 1:1 interaction model. (c) Crystal structure of OPTN-UBAN in complex with linear diubiquitin (crystallized in the presence of linear tetraubiquitin). Each subunit of OPTN is coloured green and pink, respectively. The distal and proximal ubiquitin moieties are coloured purple and cyan, respectively. Phosphorylation sites, such as Ser65 in ubiquitin and Ser473 in OPTN, are coloured orange. (d) Superimposition of the structures of OPTN·linear diubiquitin and NEMO·linear diubiquitin (grey) (PDB 2ZVN). (e) Superimposition of the structures of OPTN·linear diubiquitin and NEMO·K63 diubiquitin (grey) (PDB 3JSV).

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