Question

What is the advantage of the proteasomal active sites having different substrate specificities?

Short answer

Signals from injured cells or other immune system cells prompt the antigen-presenting cells to produce more alternative proteasomal subunits with different substrate specificities during bacterial or viral infections.

Step-by-step solution

Active β-type subunits.

The three active -type subunits have varied substrate preferences; the 1 subunit cleaves after acidic residues, the 2 subunit cleaves after basic residues, and the 5 subunit cleaves after hydrophobic residues.

Degradation of cytosolic peptidase.

The three active -type subunits have varied substrate preferences; the 1 subunit cleaves after acidic residues, the 2 subunit cleaves after basic residues, and the 5 subunit cleaves after hydrophobic residues.