Biogenesis of a mitochondrial outer membrane protein in Trypanosoma brucei : targeting signal and dependence on an unique biogenesis factor

Bruggisser, Julia; Käser, Sandro; Mani, Jan; Schneider, André (2017). Biogenesis of a mitochondrial outer membrane protein in Trypanosoma brucei : targeting signal and dependence on an unique biogenesis factor. Journal of biological chemistry, 292(8), pp. 3400-3410. American Society for Biochemistry and Molecular Biology 10.1074/jbc.M116.755983

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The mitochondrial outer membrane (OM) contains single and multiple membrane-spanning proteins which need to contain signals that ensure correct targeting and insertion into the OM. The biogenesis of such proteins has so far essentially only been studied in yeast and related organisms. Here we show that POMP10, an OM protein of the early diverging protozoan Trypanosoma brucei, is signal-anchored. Transgenic cells expressing variants of POMP10 fused to GFP demonstrate that the N-terminal membrane-spanning domain flanked by a few positively charged or neutral residues is both necessary and sufficient for mitochondrial targeting. Carbonate extraction experiments indicate that, while the presence of neutral instead of positively charged residues did not interfere with POMP10 localization, it weakened its interaction with the OM. Expression of GFP-tagged POMP10 in inducible RNAi cell lines shows that its mitochondrial localization depends on pATOM36 but does neither require Sam50 nor ATOM40, the trypanosomal analogue of the Tom40 import pore. pATOM36 is a kinetoplastid-specific OM protein that has previously been implicated in the assembly of OM proteins and in mitochondrial DNA inheritance. In summary, our results show that while the features of the targeting signal in signal-anchored proteins are widely conserved, the protein machinery that mediates their biogenesis is not.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

Graduate School:

Graduate School for Cellular and Biomedical Sciences (GCB)

UniBE Contributor:

Bruggisser, Julia; Käser, Sandro; Mani, Jan and Schneider, André

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

ISSN:

0021-9258

Publisher:

American Society for Biochemistry and Molecular Biology

Language:

English

Submitter:

Christina Schüpbach

Date Deposited:

13 Feb 2017 15:58

Last Modified:

19 Jan 2018 02:30

Publisher DOI:

10.1074/jbc.M116.755983

PubMed ID:

28100781

BORIS DOI:

10.7892/boris.94916

URI:

https://boris.unibe.ch/id/eprint/94916

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