The disorderly conduct of Hsc70 and its interaction with the Alzheimer's-related Tau protein.

Autor: Taylor IR; the Institute for Neurodegenerative Disease, University of California at San Francisco, San Francisco, California 94158, and., Ahmad A; From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109., Wu T; the Institute for Neurodegenerative Disease, University of California at San Francisco, San Francisco, California 94158, and., Nordhues BA; the Department of Molecular Medicine and Byrd Alzheimer's Institute, University of South Florida, Tampa, Florida 33613., Bhullar A; From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109., Gestwicki JE; the Institute for Neurodegenerative Disease, University of California at San Francisco, San Francisco, California 94158, and Jason.Gestwicki@ucsf.edu., Zuiderweg ERP; From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109, zuiderwe@umich.edu.
Jazyk: angličtina
Zdroj: The Journal of biological chemistry [J Biol Chem] 2018 Jul 06; Vol. 293 (27), pp. 10796-10809. Date of Electronic Publication: 2018 May 15.
DOI: 10.1074/jbc.RA118.002234
Abstrakt: Hsp70 chaperones bind to various protein substrates for folding, trafficking, and degradation. Considerable structural information is available about how prokaryotic Hsp70 (DnaK) binds substrates, but less is known about mammalian Hsp70s, of which there are 13 isoforms encoded in the human genome. Here, we report the interaction between the human Hsp70 isoform heat shock cognate 71-kDa protein (Hsc70 or HSPA8) and peptides derived from the microtubule-associated protein Tau, which is linked to Alzheimer's disease. For structural studies, we used an Hsc70 construct (called BETA) comprising the substrate-binding domain but lacking the lid. Importantly, we found that truncating the lid does not significantly impair Hsc70's chaperone activity or allostery in vitro Using NMR, we show that BETA is partially dynamically disordered in the absence of substrate and that binding of the Tau sequence GKVQIINKKG (with a K D = 500 nm) causes dramatic rigidification of BETA. NOE distance measurements revealed that Tau binds to the canonical substrate-binding cleft, similar to the binding observed with DnaK. To further develop BETA as a tool for studying Hsc70 interactions, we also measured BETA binding in NMR and fluorescent competition assays to peptides derived from huntingtin, insulin, a second Tau-recognition sequence, and a KFERQ-like sequence linked to chaperone-mediated autophagy. We found that the insulin C-peptide binds BETA with high affinity ( K D < 100 nm), whereas the others do not ( K D > 100 μm). Together, our findings reveal several similarities and differences in how prokaryotic and mammalian Hsp70 isoforms interact with different substrate peptides.
(© 2018 Taylor et al.)
Databáze: MEDLINE
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