FIG. 1.

Sequence comparison of Rpn3 homologs. The following protein sequences (sizes and accession numbers) were aligned as indicated in Materials and Methods: S. cerevisiae Rpn3/Sun2 (523 amino acids [aa]; 603613), Homo sapiens p58/S3 (534 aa; D67025), Mus musculus P91A (529 aa; G387100), Drosophila melanogaster DoxA2 (510 aa; G157285), Caenorhabditis elegans open reading frame C30C11.2 product (504 aa; G156222), and S. pombe partial open reading frame SPBC 119.01 product (437 aa; g2959362). Identical amino acids are shown in black boxes, and similar residues are shaded in gray. Dashes indicate conserved residues. The bracket above the sequences indicates the PCI domain, as defined by Hofmann and Bucher (26), which is common to all Rpn3/Sun2 homologs shown here. D.m., H.s., and S.c. arrows mark the beginnings of the Drosophila, human, and budding yeast proteins, respectively, with complementing activity of a nullizygous rpn3 mutant (32, 35).