positive regulation of protein localization to Cajal body / positive regulation of telomerase RNA localization to Cajal body / chaperonin-containing T-complex / : / BBSome-mediated cargo-targeting to cilium / Formation of tubulin folding intermediates by CCT/TriC / Folding of actin by CCT/TriC / binding of sperm to zona pellucida / Prefoldin mediated transfer of substrate to CCT/TriC / beta-tubulin binding ...positive regulation of protein localization to Cajal body / positive regulation of telomerase RNA localization to Cajal body / chaperonin-containing T-complex / : / BBSome-mediated cargo-targeting to cilium / Formation of tubulin folding intermediates by CCT/TriC / Folding of actin by CCT/TriC / binding of sperm to zona pellucida / Prefoldin mediated transfer of substrate to CCT/TriC / beta-tubulin binding / Association of TriC/CCT with target proteins during biosynthesis / : / positive regulation of telomere maintenance via telomerase / protein folding chaperone / mRNA 3'-UTR binding / ATP-dependent protein folding chaperone / response to virus / mRNA 5'-UTR binding / Cooperation of PDCL (PhLP1) and TRiC/CCT in G-protein beta folding / unfolded protein binding / G-protein beta-subunit binding / protein folding / cell body / microtubule / protein stabilization / centrosome / nucleolus / ATP hydrolysis activity / extracellular exosome / ATP binding / cytosol / cytoplasm 類似検索 - 分子機能
ジャーナル: J Biol Chem / 年: 2013 タイトル: Human CCT4 and CCT5 chaperonin subunits expressed in Escherichia coli form biologically active homo-oligomers. 著者: Oksana A Sergeeva / Bo Chen / Cameron Haase-Pettingell / Steven J Ludtke / Wah Chiu / Jonathan A King / 要旨: Chaperonins are a family of chaperones that encapsulate their substrates and assist their folding in an ATP-dependent manner. The ubiquitous eukaryotic chaperonin, TCP-1 ring complex (TRiC), is a ...Chaperonins are a family of chaperones that encapsulate their substrates and assist their folding in an ATP-dependent manner. The ubiquitous eukaryotic chaperonin, TCP-1 ring complex (TRiC), is a hetero-oligomeric complex composed of two rings, each formed from eight different CCT (chaperonin containing TCP-1) subunits. Each CCT subunit may have distinct substrate recognition and ATP hydrolysis properties. We have expressed each human CCT subunit individually in Escherichia coli to investigate whether they form chaperonin-like double ring complexes. CCT4 and CCT5, but not the other six CCT subunits, formed high molecular weight complexes within the E. coli cells that sedimented about 20S in sucrose gradients. When CCT4 and CCT5 were purified, they were both organized as two back-to-back rings of eight subunits each, as seen by negative stain and cryo-electron microscopy. This morphology is consistent with that of the hetero-oligomeric double-ring TRiC purified from bovine testes and HeLa cells. Both CCT4 and CCT5 homo-oligomers hydrolyzed ATP at a rate similar to human TRiC and were active as assayed by luciferase refolding and human γD-crystallin aggregation suppression and refolding. Thus, both CCT4 and CCT5 homo-oligomers have the property of forming 8-fold double rings absent the other subunits, and these complexes carry out chaperonin reactions without other partner subunits.