Aspergillus fumigatus Hsp90 interacts with the main components of the cell wall integrity pathway and cooperates in heat shock and cell wall stress adaptation.

Aspergillus fumigatus Hsp90 interacts with the main components of the cell wall integrity pathway and cooperates in heat shock and cell wall stress adaptation.

Cell Microbiol. 2020 Oct 03;:e13273

Authors: Rocha MC, Minari K, Fabri JHTM, Kerkaert JD, Gava LM, da Cunha AF, Cramer RA, Borges JC, Malavazi I

Abstract
The initiation of Aspergillus fumigatus infection occurs via dormant conidia deposition into the airways. Therefore, conidial germination and subsequent hyphal extension and growth occur in a sustained heat shock (HS) environment promoted by the host. The Cell Wall Integrity Pathway (CWIP) and the essential eukaryotic chaperone Hsp90 are critical for fungi to survive HS. Although A. fumigatus is a thermophilic fungus, the mechanisms underpinning the HS response are not thoroughly described and important to define its role in pathogenesis, virulence, and antifungal drug responses. Here, we investigate the contribution of the CWIP in A. fumigatus thermotolerance. We observed that the CWIP components PkcA, MpkA, and RlmA are Hsp90 clients and that a PkcAG579R mutation abolishes this interaction. PkcAG579R also abolishes MpkA activation in the short-term response to HS. Biochemical and biophysical analyses indicated that Hsp90 is a dimeric functional ATPase, which has a higher affinity for ADP than ATP and prevents MpkA aggregation in vitro. Our data suggest that the CWIP is constitutively required for A. fumigatus to cope with the temperature increase found in the mammalian lung environment, emphasizing the importance of this pathway in supporting thermotolerance and cell wall integrity. This article is protected by copyright. All rights reserved.

PMID: 33010083 [PubMed – as supplied by publisher]

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