TY - JOUR
T1 - cDNA cloning of p112, the largest regulatory subunit of the human 26S proteasome, and functional analysis of its yeast homologue, Sen3p
AU - Yokota, Kin Ya
AU - Kagawa, Susumu
AU - Shimizu, Yoshihisa
AU - Akioka, Hiroshi
AU - Tsurumi, Chizuko
AU - Noda, Chiseko
AU - Fujimuro, Masahiro
AU - Yokosawa, Hideyoshi
AU - Fujiwara, Tsutomu
AU - Takahashi, Ei Ichi
AU - Ohba, Masayuki
AU - Yamasaki, Moto o.
AU - DeMartino, George N.
AU - Slaughter, Clive A.
AU - Toh-e, Akio
AU - Tanaka, Keiji
PY - 1996/6
Y1 - 1996/6
N2 - The 26S proteasome is a large multisubunit protease complex, the largest regulatory subunit of which is a component named p112. Molecular cloning of cDNA encoding human p112 revealed a polypeptide predicted to have 953 amino acid residues and a molecular mass of 105,865. The human p112 gene was mapped to the q37.1-q37.2 region of chromosome 2. Computer analysis showed that p112 has strong similarity to the Saccharomyces cerevisiae Sen3p, which has been listed in a gene bank as a factor affecting tRNA splicing endonuclease. The SEN3 also was identified in a synthetic lethal screen with the nin1-1 mutant, a temperature-sensitive mutant of NIN1. NIN1 encodes p31, another regulatory subunit of the 26S proteasome, which is necessary for activation of Cdc28p kinase. Disruption of the SEN3 did not affect cell viability, but led to temperature-sensitive growth. The human p112 cDNA suppressed the growth defect at high temperature in a SEN3 disruptant, indicating that p112 is a functional homologue of the yeast Sen3p. Maintenance of SEN3 disruptant cells at the restrictive temperature resulted in a variety of cellular dysfunctions, including defects in proteolysis mediated by the ubiquitin pathway, in the N-end rule system, in the stress response upon cadmium exposure, and in nuclear protein transportation. The functional abnormality induced by SEN3 disruption differs considerably from various phenotypes shown by the nin1-1 mutation, suggesting that these two regulatory subunits of the 26S proteasome play distinct roles in the various processes mediated by the 26S proteasome.
AB - The 26S proteasome is a large multisubunit protease complex, the largest regulatory subunit of which is a component named p112. Molecular cloning of cDNA encoding human p112 revealed a polypeptide predicted to have 953 amino acid residues and a molecular mass of 105,865. The human p112 gene was mapped to the q37.1-q37.2 region of chromosome 2. Computer analysis showed that p112 has strong similarity to the Saccharomyces cerevisiae Sen3p, which has been listed in a gene bank as a factor affecting tRNA splicing endonuclease. The SEN3 also was identified in a synthetic lethal screen with the nin1-1 mutant, a temperature-sensitive mutant of NIN1. NIN1 encodes p31, another regulatory subunit of the 26S proteasome, which is necessary for activation of Cdc28p kinase. Disruption of the SEN3 did not affect cell viability, but led to temperature-sensitive growth. The human p112 cDNA suppressed the growth defect at high temperature in a SEN3 disruptant, indicating that p112 is a functional homologue of the yeast Sen3p. Maintenance of SEN3 disruptant cells at the restrictive temperature resulted in a variety of cellular dysfunctions, including defects in proteolysis mediated by the ubiquitin pathway, in the N-end rule system, in the stress response upon cadmium exposure, and in nuclear protein transportation. The functional abnormality induced by SEN3 disruption differs considerably from various phenotypes shown by the nin1-1 mutation, suggesting that these two regulatory subunits of the 26S proteasome play distinct roles in the various processes mediated by the 26S proteasome.
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U2 - 10.1091/mbc.7.6.853
DO - 10.1091/mbc.7.6.853
M3 - Article
C2 - 8816993
AN - SCOPUS:8944250216
SN - 1059-1524
VL - 7
SP - 853
EP - 870
JO - Molecular Biology of the Cell
JF - Molecular Biology of the Cell
IS - 6
ER -