Proteasome-dependent degradation serves an essential role in the removal of a wide variety of key nuclear and cytosolic proteins. Substrates are targeted for proteolysis by the ubiquitin pathway before being degraded by the 26 S proteasome. The subunit of the proteasome, S5a, was identified to bind to polyubiquitin in vitro and thus proposed to act as a substrate recognition component. Immunogen: Drosophila 26S Proteasome subunit S5a also known as Rpn 10 or p54