Bood POZ containing gene type 2 is a human counterpart of yeast Btb3p and promotes the degradation of terminal deoxynucleotidyltransferase.
Bood POZ containing gene type 2 (BPOZ-2) is involved in the growth suppressive effect of the phosphatase and tensin homologue (PTEN). We showed that BPOZ-2 is a human counterpart of yeast Btb3p, which is a putative adaptor for Pcu3p-based ubiquitin ligase. BPOZ-2 bound to E3 ligase CUL3 in vitro and in vivo. BPOZ-2 itself was ubiquitinated through the CUL3-based E3 ligase mainly within the nucleus and degraded by the 26S proteasome. Although BPOZ-2 was mainly expressed within the cytoplasm, it accumulated within the nucleus in the presence of the specific 26S proteasome inhibitor MG132. BPOZ-2 may be recruited to the nucleus from the cytoplasm. Terminal deoxynucleotidyltransferase (TdT) was detected as a BPOZ-2-binding protein using a yeast two-hybrid system by screening a human thymus cDNA library. TdT, BPOZ-2, and CUL3 formed a ternary complex in vivo. TdT was ubiquitinated only within the nucleus and degraded by the 26S proteasome. The ubiqutination or degradation of TdT was markedly promoted by co-expression of BPOZ-2 and CUL3 or BPOZ-2 in 293T cells, respectively.
Maezawa
So
S
Faculty of Science and Technology, Department of Applied Biological Science, Tokyo University of Science, Noda, Chiba 278-8510, Japan. j6407705@ed.noda.tus.ac.jp
Hayano
Takahide
T
Koiwai
Kotaro
K
Fukushima
Rie
R
Kouda
Kousuke
K
Kubota
Takashi
T
Koiwai
Osamu
O
D002460:Cell Line; D044842:Cullin Proteins / Q000378:metabolism; D004253:DNA Nucleotidylexotransferase / Q000378:metabolism*; D006801:Humans; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins; D020798:Two-Hybrid System Techniques; D025801:Ubiquitin / Q000378:metabolism; D054875:Ubiquitination
C402243:ABTB1 protein, human; C503645:CUL3 protein, human; D044842:Cullin Proteins; D012097:Repressor Proteins; D029702:Schizosaccharomyces pombe Proteins; D025801:Ubiquitin; D004253:DNA Nucleotidylexotransferase; D046988:Proteasome Endopeptidase Complex