Identification of proteins interacting with the mitochondrial small heat shock protein Hsp22 of Drosophila melanogaster: Implication in mitochondrial homeostasis

PLoS One. 2018 Mar 6;13(3):e0193771. doi: 10.1371/journal.pone.0193771. eCollection 2018.

Abstract

The small heat shock protein (sHsp) Hsp22 from Drosophila melanogaster (DmHsp22) is part of the family of sHsps in this diptera. This sHsp is characterized by its presence in the mitochondrial matrix as well as by its preferential expression during ageing. Although DmHsp22 has been demonstrated to be an efficient in vitro chaperone, its function within mitochondria in vivo remains largely unknown. Thus, determining its protein-interaction network (interactome) in the mitochondrial matrix would help to shed light on its function(s). In the present study we combined immunoaffinity conjugation (IAC) with mass spectroscopy analysis of mitochondria from HeLa cells transfected with DmHsp22 in non-heat shock condition and after heat shock (HS). 60 common DmHsp22-binding mitochondrial partners were detected in two independent IACs. Immunoblotting was used to validate interaction between DmHsp22 and two members of the mitochondrial chaperone machinery; Hsp60 and Hsp70. Among the partners of DmHsp22, several ATP synthase subunits were found. Moreover, we showed that expression of DmHsp22 in transiently transfected HeLa cells increased maximal mitochondrial oxygen consumption capacity and ATP contents, providing a mechanistic link between DmHsp22 and mitochondrial functions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster
  • Fluorescent Antibody Technique
  • HeLa Cells
  • Heat-Shock Proteins / metabolism*
  • Homeostasis / physiology*
  • Humans
  • Immunoblotting
  • Mass Spectrometry
  • Mitochondria / metabolism*
  • Mitochondrial Proton-Translocating ATPases / metabolism
  • Oxygen Consumption / physiology
  • Thermotolerance / physiology
  • Transfection

Substances

  • Drosophila Proteins
  • Heat-Shock Proteins
  • Hsp22 protein, Drosophila
  • Adenosine Triphosphate
  • Mitochondrial Proton-Translocating ATPases

Grants and funding

This work has been supported by grants from the Canadian Institutes of Health Research (CIHR) to RMT and a scholarship from PROTEO to AD. The authors would like to thank Dr. Sylvie Bourassa from Proteomics platform of CHU de Quebec Research Center-CHUL for help with Mass Spectrometry. The work of E. Hebert-Chatelain is supported by the Alzheimer Society of Canada, Brain Canada, Natural Sciences and Engineering Research Council (NSERC), Canadian Breast Cancer Foundation, New Brunswick Innovation Foundation, New Brunswick Health Research Foundation 606 and Université de Moncton. N. Pichaud is supported by grants from the NSERC and the Université de Moncton.