Nin1p, a regulatory subunit of the 26S proteasome, is necessary for activation of Cdc28p kinase of Saccharomyces cerevisiae.
The nin1-1 mutant of Saccharomyces cerevisiae cannot perform the G1/S and G2/M transitions at restrictive temperatures. At such temperatures, nin1-1 strains fail to activate histone H1 kinase after release from alpha factor-imposed G1 block and after release from hydroxyurea-imposed S block. The nin1-1 mutation shows synthetic lethality with certain cdc28 mutant alleles such as cdc28-IN. Two lines of evidence indicate that Nin1p is a component of the 26S proteasome complex: (i) Nin1p, as well as the known component of the 26S proteasome, shifted to the 26S proteasome peak in the glycerol density gradient after preincubation of crude extract with ATP-Mg2+, and (ii) nin1-1 cells accumulated polyubiquitinated proteins under restrictive conditions. These results suggest that activation of Cdc28p kinase requires proteolysis. We have cloned a human cDNA encoding a regulatory subunit of the 26S proteasome, p31, which was found to be a homolog of Nin1p.
Kominami
K
K
Department of Plant Sciences, Graduate School of Science, University of Tokyo, Japan.
DeMartino
G N
GN
Moomaw
C R
CR
Slaughter
C A
CA
Shimbara
N
N
Fujimuro
M
M
Yokosawa
H
H
Hisamatsu
H
H
Tanahashi
N
N
Shimizu
Y
Y
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001704:Biopolymers / Q000378:metabolism; D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism*; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D004789:Enzyme Activation; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005804:Genes, Lethal; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D025821:Polyubiquitin; D046988:Proteasome Endopeptidase Complex; D011506:Proteins / Q000235:genetics; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D014452:Ubiquitins / Q000378:metabolism
D001704:Biopolymers; D005656:Fungal Proteins; C501479:PSMD8 protein, human; D011506:Proteins; C074096:RPN12 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014452:Ubiquitins; D025821:Polyubiquitin; D017489:CDC28 Protein Kinase, S cerevisiae; D010447:Peptide Hydrolases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease