Structural and functional studies of the Leishmania braziliensis SGT co-chaperone indicate that it shares structural features with HIP and can interact with both Hsp90 and Hsp70 with similar affinities

Author(s)

Coto, Amanda L. S. ; Seraphim, Thiago V. ; Batista, Fernanda A. H. ; Dores-Silva, Paulo R. ; Barranco, Ana Beatriz F. ; Teixeira, Felipe R. ; Gava, Lisandra M. ; Borges, Julio C.

• Document type: Journal article
• Source: International Journal of Biological Macromolecules; v. 118, p. 14-pg., 2018-10-15.

Abstract

Molecular chaperones and co-chaperones play an essential role in the life cycles of protozoa belonging to the genus Leishmania. The small glutamine-rich TPR-containing protein (SGT) is a co-chaperone that can be divided into three domains: N-terminal, tetratricopeptide (TPR) and C-terminal. The TPR domain is responsible for interactions with both Hsp70 and Hsp90; however, the mechanism of interaction and the functionality of SGT are unclear. In this context, we present the structural and functional characterization of Leishmania braziliensis SGT (LbSGT), aiming to elucidate how this co-chaperone interacts with the Hsp90/Hsp70 chaperone machinery. Structurally, the recombinant LbSGT behaves as an alpha-helical, multidomain and elongated dimer in solution. Despite their low amino acid sequence identity and similarity, LbSGT shares structural properties and domain organization with the Hsp70-interacting protein (HIP) co-chaperone. Functionally, LbSGT is a cognate protein in L. braziliensis promastigote cells and interacts indiscriminately, with similar affinities, with both Hsp90 and Hsp70 chaperones, capable of working as an adaptor protein. Sequence analysis indicates that LbSGT interacts via a dicarboxylate clamp, the same mechanism used by the Hsp90-Hsp70-organizing protein (HOP) cochaperone. These results suggest that SGT can develop the same function as HOP but using the HIP structural scaffold. (C) 2018 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 12/50161-8 - Study of the structure and function of the Hsp90 chaperone with emphasis on its role in cellular homeostasis
• Grantee: Carlos Henrique Inacio Ramos
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/07335-9 - Studies of human HSP70 isoforms residing in the cytoplasm and mitochondria and their high molecular weight oligomers: interaction with co-chaperones and client proteins
• Grantee: Julio Cesar Borges
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/07206-6 - Studies of the mitochondrial HSP70 of human and protozoa: structural and functional approaches
• Grantee: Julio Cesar Borges
• Support Opportunities: Regular Research Grants