An Archaeal Homolog of Proteasome Assembly Factor Functions as a Proteasome Activator (original) (raw)
Figure 2
PbaB functions as a proteasome activator through the HbYX motif.
PbaB accelerated proteasomal degradation of (A) fluorogenic nonapeptide substrate (LFP) and (B) α-synuclein in an HbYX motif-dependent manner. Mixture of the wild-type 20S proteasome and LFP or α-synuclein was incubated in the presence and absence of PbaB. The proteasomal activation by PbaB was independent of 1 mM ATP and was compromised by a K68A mutation. Gate-less mutant (NΔ2-14 proteasome α subunit from P. furiosus) had greater activities for LFP or α-synuclein hydrolysis, which was not further activated by PbaB. Error bars represent s.e.m. (n = 3).