TY - JOUR
T1 - Interaction of hHR23 with S5a. The ubiquitin-like domain of hHR23 mediates interaction with S5a subunit of 26 S proteasome
AU - Hiyama, Hideki
AU - Yokoi, Masayuki
AU - Masutani, Chikahide
AU - Sugasawa, Kaoru
AU - Maekawa, Takafumi
AU - Tanaka, Keiji
AU - Hoeijmakers, Jan H.J.
AU - Hanaoka, Fumio
PY - 1999/9/24
Y1 - 1999/9/24
N2 - hHR23B is one of two human homologs of the Saccharomyces cerevisiae nucleotide excision repair (NER) gene product RAD23 and a component of a protein complex that specifically complements the NER defect of xeroderma pigmentosum group C (XP-C) cell extracts in vitro. Although a small proportion of hHR23B is tightly complexed with the XP-C responsible gene product, XPC protein, a vast majority exists as an XPC-free form, indicating that hHR23B has additional functions other than NER in vivo. Here we demonstrate that the human NER factor hHR23B as well as another human homolog of RAD23, hHR23A, interact specifically with S5a, a subunit of the human 26 S proteasome using the yeast two-hybrid system. Furthermore, hHR23 proteins were detected with S5a at the position where 26 S proteasome sediments in glycerol gradient centrifugation of HeLa S100 extracts. Intriguingly, hHR23B showed the inhibitory effect on the degradation of 125I-lysozyme in the rabbit reticulocyte lysate, hHR23 proteins thus appear to associate with 26 S proteasome in vivo. From co-precipitation experiments using several series of deletion mutants, we defined the domains in hHR23B and S5a that mediate this interaction. From these results, we propose that part of hHR23 proteins are involved in the proteolytic pathway in cells.
AB - hHR23B is one of two human homologs of the Saccharomyces cerevisiae nucleotide excision repair (NER) gene product RAD23 and a component of a protein complex that specifically complements the NER defect of xeroderma pigmentosum group C (XP-C) cell extracts in vitro. Although a small proportion of hHR23B is tightly complexed with the XP-C responsible gene product, XPC protein, a vast majority exists as an XPC-free form, indicating that hHR23B has additional functions other than NER in vivo. Here we demonstrate that the human NER factor hHR23B as well as another human homolog of RAD23, hHR23A, interact specifically with S5a, a subunit of the human 26 S proteasome using the yeast two-hybrid system. Furthermore, hHR23 proteins were detected with S5a at the position where 26 S proteasome sediments in glycerol gradient centrifugation of HeLa S100 extracts. Intriguingly, hHR23B showed the inhibitory effect on the degradation of 125I-lysozyme in the rabbit reticulocyte lysate, hHR23 proteins thus appear to associate with 26 S proteasome in vivo. From co-precipitation experiments using several series of deletion mutants, we defined the domains in hHR23B and S5a that mediate this interaction. From these results, we propose that part of hHR23 proteins are involved in the proteolytic pathway in cells.
UR - http://www.scopus.com/inward/record.url?scp=0033600798&partnerID=8YFLogxK
U2 - 10.1074/jbc.274.39.28019
DO - 10.1074/jbc.274.39.28019
M3 - Article
C2 - 10488153
AN - SCOPUS:0033600798
SN - 0021-9258
VL - 274
SP - 28019
EP - 28025
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 39
ER -