Functional Analysis of Proposed Substrate-binding Residues of Hsp104
Overview
Affiliations
Hsp104 is a hexameric AAA+ yeast disaggregase capable of solubilizing disordered aggregates and amyloid. Hsp104 couples ATP hydrolysis to polypeptide translocation through its central channel. Substrate binding by Hsp104 is mediated primarily by two conserved tyrosine residues in nucleotide binding domain (NBD) 1 and NBD2. Recent structural studies have revealed that an additional tyrosine residue (Y650) located in NBD2 appears to contact substrate and may play an important role in Hsp104 function. Here, we functionally analyze the properties of this proposed Hsp104 -substrate interaction. We find that Y650 is not essential for Hsp104 to confer thermotolerance. Supporting these findings, in a potentiated Hsp104 variant background, the Y650A mutation does not abolish potentiation. However, modulation of this site does have subtle effects on the activity of this potentiated Hsp104 variant. We therefore suggest that while Y650 is not essential for Hsp104 function, its modulation may be useful for fine-tuning Hsp104 properties.
Hsp70 chaperones, Ssa1 and Ssa2, limit poly(A) binding protein aggregation.
Buchholz H, Martin S, Dorweiler J, Radtke C, Knier A, Beans N bioRxiv. 2025; .
PMID: 39896508 PMC: 11785122. DOI: 10.1101/2025.01.17.633617.
The middle domain of Hsp104 can ensure substrates are functional after processing.
Buchholz H, Dorweiler J, Guereca S, Wisniewski B, Shorter J, Manogaran A PLoS Genet. 2024; 20(10):e1011424.
PMID: 39361717 PMC: 11478891. DOI: 10.1371/journal.pgen.1011424.
Unique structural features govern the activity of a human mitochondrial AAA+ disaggregase, Skd3.
Cupo R, Rizo A, Braun G, Tse E, Chuang E, Gupta K Cell Rep. 2022; 40(13):111408.
PMID: 36170828 PMC: 9584538. DOI: 10.1016/j.celrep.2022.111408.
Drivers of Hsp104 potentiation revealed by scanning mutagenesis of the middle domain.
Ryan J, Bao A, Bell B, Ling C, Jackrel M Protein Sci. 2021; 30(8):1667-1685.
PMID: 34010483 PMC: 8284572. DOI: 10.1002/pro.4126.