MOLECULAR-CLONING AND EXPRESSION OF SUBUNIT-12 - A NON-MCP AND NON-ATPASE SUBUNIT OF THE 26-S-PROTEASE

A cDNA encoding subunit 12 (S12) of human erythrocyte 26 S protease ha s been isolated, sequenced and expressed. The cDNA contains an open re ading frame that encodes a 36.6 kDA protein 96% identical to mouse Mov -34 and 67% identical to its Drosophila melanogaster homolog. Based on the high degree of sequence identity between human S12, mouse and Dro sophila Mov-34 proteins, we conclude that the Mov-34 gene product is a component of the 26 S protease. Antibodies produced against two S12 f ragments, Met(1)-Tyr(95) (S12(f95)) and Met(1)-Leu(205) (S12(f205)), r eact with S12 transferred to nitrocellulose from SDS-PAGE, In contrast , after transfer from native gels, the epitope(s) recognized by anti-S 12(f205) is exposed in the regulatory complex but appears to be masked when the regulatory complex associates with the multicatalytic protea se.