Phosphorylation of the outer membrane mitochondrial protein OM64 influences protein import into mitochondria

Autoren

Catharina Nickel
Regina Horneff
Ralf Heermann
Boris Neumann
Kirsten Jung
Jürgen Soll
Serena Schwenkert

DOI

10.1016/j.mito.2018.01.005

ISSN

1567-7249

Zeitschrift

Mitochondrion

Sprache

en

Paginierung

93 - 102

Datum der Veröffentlichung

2019

Status

Published

Herausgeber

Elsevier BV

Herausgeber URL

http://dx.doi.org/10.1016/j.mito.2018.01.005

Datum der Datenerfassung

2018

Titel

Phosphorylation of the outer membrane mitochondrial protein OM64 influences protein import into mitochondria

Ausgabe der Zeitschrift

44

Data source: Crossref

Abstract

Mitochondrial localized proteins are mostly synthesized in the cytosol and translocated across the outer mitochondrial membrane via the translocase of the outer membrane (TOM) complex. Although the channel protein is conserved among eukaryotes, the receptor proteins are more divergent and show features specific to the plant lineage. OM64, which is a paralogue of the chloroplast docking protein Toc64, is unique to plants. However, due to the presence of a cytosolic exposed TPR domain it might functionally replace yeast/mammalian Tom70, which is not found in plant mitochondria, by interacting with the C-terminal (M)EEVD motif of the heat shock proteins Hsp90 and Hsp70. In this study, we show that OM64 is phosphorylated within its TPR domain. Using isothermal titration calorimetry it could be demonstrated that phosphorylation reduces the binding affinity of OM64 to Hsp90. Moreover, in vivo expression of genes encoding different OM64 variants in planta revealed that phosphorylation of OM64 impairs the import efficiency of the mitochondrial preprotein pFAD, a subunits of the mitochondrial ATP synthase. In summary, our data provide significant insight into the fine-tuning mechanisms of mitochondrial protein import mediated by phosphorylation of the cytosolic exposed receptor protein OM64.

Addresses

Munich Center for Integrated Protein Science at the Ludwig-Maximilians-Universität München, Department of Biology I, Botany, Großhaderner Straße 2-4, D-82152 Martinsried, Germany.

Autoren

Catharina Nickel
Regina Horneff
Ralf Heermann
Boris Neumann
Kirsten Jung
Jürgen Soll
Serena Schwenkert

DOI

10.1016/j.mito.2018.01.005

eISSN

1872-8278

Externe Identifier

PubMed Identifier: 29374544

Funding acknowledgements

Deutsche Forschungsgemeinschaft: SFB1035

Open access

false

ISSN

1567-7249

Zeitschrift

Mitochondrion

Schlüsselwörter

Mitochondria
Arabidopsis
Mitochondrial Membrane Transport Proteins
Arabidopsis Proteins
Calorimetry
Protein Processing, Post-Translational
Protein Binding
Protein Transport
Phosphorylation
HSP90 Heat-Shock Proteins

Sprache

eng

Medium

Print-Electronic

Online publication date

2018

Paginierung

93 - 102

Datum der Veröffentlichung

2019

Status

Published

Datum der Datenerfassung

2018

Titel

Phosphorylation of the outer membrane mitochondrial protein OM64 influences protein import into mitochondria.

Sub types

Research Support, Non-U.S. Gov't
Journal Article

Ausgabe der Zeitschrift

44

Data source: Europe PubMed Central

Abstract

Mitochondrial localized proteins are mostly synthesized in the cytosol and translocated across the outer mitochondrial membrane via the translocase of the outer membrane (TOM) complex. Although the channel protein is conserved among eukaryotes, the receptor proteins are more divergent and show features specific to the plant lineage. OM64, which is a paralogue of the chloroplast docking protein Toc64, is unique to plants. However, due to the presence of a cytosolic exposed TPR domain it might functionally replace yeast/mammalian Tom70, which is not found in plant mitochondria, by interacting with the C-terminal (M)EEVD motif of the heat shock proteins Hsp90 and Hsp70. In this study, we show that OM64 is phosphorylated within its TPR domain. Using isothermal titration calorimetry it could be demonstrated that phosphorylation reduces the binding affinity of OM64 to Hsp90. Moreover, in vivo expression of genes encoding different OM64 variants in planta revealed that phosphorylation of OM64 impairs the import efficiency of the mitochondrial preprotein pFAD, a subunits of the mitochondrial ATP synthase. In summary, our data provide significant insight into the fine-tuning mechanisms of mitochondrial protein import mediated by phosphorylation of the cytosolic exposed receptor protein OM64.

Date of acceptance

2018

Autoren

Catharina Nickel
Regina Horneff
Ralf Heermann
Boris Neumann
Kirsten Jung
Jürgen Soll
Serena Schwenkert

Autoren-URL

https://www.ncbi.nlm.nih.gov/pubmed/29374544

DOI

10.1016/j.mito.2018.01.005

eISSN

1872-8278

Zeitschrift

Mitochondrion

Schlüsselwörter

Arabidopsis thaliana
Hsp90
Mitochondria
Protein import
TPR domain
Arabidopsis
Arabidopsis Proteins
Calorimetry
HSP90 Heat-Shock Proteins
Mitochondria
Mitochondrial Membrane Transport Proteins
Phosphorylation
Protein Binding
Protein Processing, Post-Translational
Protein Transport

Sprache

eng

Country

Netherlands

Paginierung

93 - 102

PII

S1567-7249(17)30154-X

Datum der Veröffentlichung

2019

Status

Published

Datum, an dem der Datensatz öffentlich gemacht wurde

2019

Titel

Phosphorylation of the outer membrane mitochondrial protein OM64 influences protein import into mitochondria.

Sub types

Journal Article
Research Support, Non-U.S. Gov't

Ausgabe der Zeitschrift

44

Data source: PubMed

Phosphorylation of the outer membrane mitochondrial protein OM64 influences protein import into mitochondria

Tools