CADp44: a novel regulatory subunit of the 26S proteasome and the mammalian homolog of yeast Sug2p.
We have identified a novel protein, CADp44, based on the analysis of cDNAs derived from the brainstem of the 13-lined ground squirrel, Spermophilus tridecemlineatus. CADp44 has an unmodified molecular mass of 44,178 Da and contains multiple functional domains, including a conserved ATPase domain (CAD) and a leucine zipper motif. We show that distinct regions of the CADp44 sequence are identical to a set of peptides prepared from a recently identified bovine protein, referred to as p42, which is found in the PA700 regulatory complex of the 26S proteasome (DeMartino et al., 1996). We also show that CADp44 is the functional homolog of the newly characterized Sug2 protein from the budding yeast, Saccharomyces cerevisiae (Russell et al., 1996). Consistent with its role as a component of the 26S proteasome, CADp44 mRNA is found in all ground squirrel tissues examined. Evolutionary relationships based on sequence analysis show that both CADp44 and yeast Sug2p are distinct from the other five CAD ATPases found in the PA700, and together comprise the sixth and newest CAD subunit of the regulatory complex of the 26S proteasome.
Bauer
V W
VW
Department of Genetics, North Carolina State University, Raleigh 27695-7614, USA.
Swaffield
J C
JC
Johnston
S A
SA
Andrews
M T
MT
D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000032:analysis* / Q000737:chemistry / Q000145:classification / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000737:chemistry; D015870:Gene Expression; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000737:chemistry*; D046988:Proteasome Endopeptidase Complex; D012441:Saccharomyces cerevisiae; D012589:Sciuridae; D017386:Sequence Homology, Amino Acid
D005656:Fungal Proteins; D010447:Peptide Hydrolases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease; D000251:Adenosine Triphosphatases; D000074183:ATPases Associated with Diverse Cellular Activities; C102757:PSMC6 protein, Spermophilus tridecemlineatus