title: Isolation and characterization of SUG2. A novel ATPase family component of the yeast 26 S proteasome.
abstract: Using a genetic strategy designed to find proteins involved in the function of the Saccharomyces cerevisiae transcriptional activator GAL4, we isolated mutants in two genes which rescue a class of gal4 activation domain mutants. One of these genes, SUG1, encodes a member of a large family of putative ATPases, the Conserved ATPase containing Domain (CAD) proteins (also known as AAA proteins) that are involved in a wide variety of cellular functions. Subsequently, SUG1 was identified as a subunit of the 26 S proteasome. We have now cloned the gene defined by the second complementation group. SUG2 encodes an essential 49-kDa protein that is also a member of the CAD family and is 43% identical to SUG1. The mutation in sug2-1, like that in sug1-1, is found in the CAD near the highly conserved ATPase motif. We present biochemical and genetic evidence that SUG2 is associated in vivo with SUG1 and is a novel CAD protein subunit of the 26 S proteasome. With its highly conserved mammalian homologs, human p42 and ground squirrel CADp44, SUG2 defines a new class of proteasomal CAD proteins.
authors.affiliation: Department of Internal Medicine, Graduate Program in Biochemistry and Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75235-8573, USA. Johnston@ryburn.swmed.edu
authors.forename: S J
authors.initials: SJ
authors.lastname: Russell
authors.forename: U G
authors.initials: UG
authors.lastname: Sathyanarayana
authors.forename: S A
authors.initials: SA
authors.lastname: Johnston
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000302:isolation & purification* / Q000648:ultrastructure; D000595:Amino Acid Sequence; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D005656:Fungal Proteins / Q000235:genetics / Q000302:isolation & purification*; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D016297:Mutagenesis, Site-Directed; D046988:Proteasome Endopeptidase Complex; D011485:Protein Binding; D017433:Protein Structure, Secondary; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship
chemical_list: D005656:Fungal Proteins; D046911:Macromolecular Substances; D009097:Multienzyme Complexes; D029701:Saccharomyces cerevisiae Proteins; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases; C103015:RPT4 protein, S cerevisiae