The Hsp90 cochaperone TTT promotes cotranslational maturation of PIKK kinases prior to complex assembly
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ABSTRACT: PIKKs are a family of kinases that control fundamental processes, including cell growth, DNA damage repair, and gene expression. Although their regulation and activities are well characterized, little is known about how PIKKs fold and assemble into active complexes. Previous work identified an Hsp90 cochaperone, the TTT complex, which specifically stabilizes PIKKs. Here we describe a mechanism by which TTT promotes their de novo maturation in fission yeast. We show that TTT recognizes newly synthesized PIKKs during translation. Although PIKKs form multimeric complexes, we found that they do not engage in cotranslational assembly with their partners. Rather, we accumulated evidence that TTT protects nascent PIKK polypeptides from misfolding and degradation and that PIKKs acquire their native state after translation is terminated. Thus, PIKK maturation and assembly are temporally segregated, suggesting that the biogenesis of large complexes requires both dedicated chaperones and cotranslational interactions between subunits.
INSTRUMENT(S): Q Exactive Plus
ORGANISM(S): Schizosaccharomyces Pombe 972h-
TISSUE(S): Cell Culture
SUBMITTER: Functional Proteomics Platform FPP
LAB HEAD: Dominique Helmlinger
PROVIDER: PXD028351 | Pride | 2021-09-10
REPOSITORIES: Pride
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