Open AccessAn Archaeal Homolog of Proteasome Assembly Factor Functions as a Proteasome Activator
Author(s) -
Kentaro Kumoi,
Tadashi Satoh,
Kazuyoshi Murata,
Takeshi Hiromoto,
Tsunehiro Mizushima,
Yukiko Kamiya,
Masanori Noda,
Susumu Uchiyama,
Hirokazu Yagi,
Koichi Kato
Publication year - 2013
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0060294
Subject(s) - proteasome , homotetramer , biology , microbiology and biotechnology , activator (genetics) , chaperone (clinical) , protein subunit , biochemistry , gene , medicine , pathology
Assembly of the eukaryotic 20S proteasome is an ordered process involving several proteins operating as proteasome assembly factors including PAC1-PAC2 but archaeal 20S proteasome subunits can spontaneously assemble into an active cylindrical architecture. Recent bioinformatic analysis identified archaeal PAC1-PAC2 homologs PbaA and PbaB. However, it remains unclear whether such assembly factor-like proteins play an indispensable role in orchestration of proteasome subunits in archaea. We revealed that PbaB forms a homotetramer and exerts a dual function as an ATP-independent proteasome activator and a molecular chaperone through its tentacle-like C-terminal segments. Our findings provide insights into molecular evolution relationships between proteasome activators and assembly factors.