Dataset Information

Conserved conformational selection mechanism of Hsp70 chaperone-substrate interactions.

ABSTRACT: Molecular recognition is integral to biological function and frequently involves preferred binding of a molecule to one of several exchanging ligand conformations in solution. In such a process the bound structure can be selected from the ensemble of interconverting ligands a priori (conformational selection, CS) or may form once the ligand is bound (induced fit, IF). Here we focus on the ubiquitous and conserved Hsp70 chaperone which oversees the integrity of the cellular proteome through its ATP-dependent interaction with client proteins. We directly quantify the flux along CS and IF pathways using solution NMR spectroscopy that exploits a methyl TROSY effect and selective isotope-labeling methodologies. Our measurements establish that both bacterial and human Hsp70 chaperones interact with clients by selecting the unfolded state from a pre-existing array of interconverting structures, suggesting a conserved mode of client recognition among Hsp70s and highlighting the importance of molecular dynamics in this recognition event.

SUBMITTER: Sekhar A

PROVIDER: S-EPMC5819949 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

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Conserved conformational selection mechanism of Hsp70 chaperone-substrate interactions.

Sekhar Ashok A Velyvis Algirdas A Zoltsman Guy G Rosenzweig Rina R Bouvignies Guillaume G Kay Lewis E LE

eLife 20180220

Molecular recognition is integral to biological function and frequently involves preferred binding of a molecule to one of several exchanging ligand conformations in solution. In such a process the bound structure can be selected from the ensemble of interconverting ligands <i>a priori</i> (conformational selection, CS) or may form once the ligand is bound (induced fit, IF). Here we focus on the ubiquitous and conserved Hsp70 chaperone which oversees the integrity of the cellular proteome throug ...[more]

PMID: 29460778

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Project description:CK2, a serine/threonine (Ser/Thr) kinase present in eukaryotic cells, is known to have a vast number of substrates. We have recently shown that it localizes to nuclei and at pores between hyphal compartments in Magnaporthe oryzae We performed a pulldown proteomics analysis of M. oryzae CK2 catalytic subunit MoCKa to detect interacting proteins. The MoCKa pulldown was enriched for septum and nucleolus proteins and intrinsically disordered proteins (IDPs) containing a CK2 phosphorylation motif that is proposed to destabilize and unfold ?-helices. This points to a function for CK2 phosphorylation and corresponding phosphatase dephosphorylation in the formation of functional protein-protein aggregates and protein-RNA/DNA binding. To test this as widely as possible, we used secondary data downloaded from databases from a large range of M. oryzae experiments, as well as data for a relatively closely related plant-pathogenic fungus, Fusarium graminearum We found that CKa expression was strongly positively correlated with Ser/Thr phosphatases, as well as with disaggregases (HSP104, YDJ1, and SSA1) and an autophagy-indicating protein (ATG8). The latter points to increased protein aggregate formation at high levels of CKa expression. Our results suggest a general role for CK2 in chaperoning aggregation and disaggregation of IDPs and their binding to proteins, DNA, and RNA.IMPORTANCE CK2 is a eukaryotic conserved kinase enzyme complex that phosphorylates proteins. CK2 is known to phosphorylate a large number of proteins and is constitutively active, and thus a "normal" role for a kinase in a signaling cascade might not be the case for CK2. Previous results on localization and indications from the literature point to a function for CK2 phosphorylation in shaping and folding of proteins, especially intrinsically disordered proteins, which constitute about 30% of eukaryotic proteins. We used pulldown of interacting proteins and data downloaded from a large range of transcriptomic experiments in M. oryzae and complemented these with data downloaded from a large range of transcriptomic experiments in Fusarium graminearum We found support for a general role for CK2 in aggregation and disaggregation of IDPs and their binding to proteins, DNA, and RNA-interactions that could explain the importance of CK2 in eukaryotic cell function and disease.

Dataset Information

Conserved conformational selection mechanism of Hsp70 chaperone-substrate interactions.

Publications

Conserved conformational selection mechanism of Hsp70 chaperone-substrate interactions.

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