This is C-terminal to the Mov24 region of the yeast proteasomal subunit Rpn11 and seems likely to regulate the mitochondrial fission and tubulation processes, ie the outer mitochondrial membrane proteins. This function appears to be unrelated to the proteasome activity of the N-terminal region [1].

1: Dissection of the carboxyl-terminal domain of the proteasomal subunit Rpn11 in maintenance of mitochondrial structure and function. Rinaldi T, Hofmann L, Gambadoro A, Cossard R, Livnat-Levanon N, Glickman MH, Frontali L, Delahodde A; Mol Biol Cell. 2008;19:1022-1031. PMID:18172023