tRNA import across the mitochondrial inner membrane in T. brucei requires TIM subunits but is independent of protein import

Shikha, Shikha; Huot, Jonathan L.; Schneider, André; Niemann, Moritz (2020). tRNA import across the mitochondrial inner membrane in T. brucei requires TIM subunits but is independent of protein import. Nucleic acids research, 48(21), pp. 12269-12281. Oxford University Press 10.1093/nar/gkaa1098

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Mitochondrial tRNA import is widespread, but mechanistic insights of how tRNAs are translocated across mitochondrial membranes remain scarce. The parasitic protozoan T. brucei lacks mitochondrial tRNA genes. Consequently, it imports all organellar tRNAs from the cytosol. Here we investigated the connection between tRNA and protein translocation across the mitochondrial inner membrane. Trypanosomes have a single inner membrane protein translocase that consists of three heterooligomeric submodules, which all are required for import of matrix proteins. In vivo depletion of individual submodules shows that surprisingly only the integral membrane core module, including the protein import pore, but not the presequence-associated import motor are required for mitochondrial tRNA import. Thus we could uncouple import of matrix proteins from import of tRNAs even though both substrates are imported into the same mitochondrial subcompartment. This is reminiscent to the outer membrane where the main protein translocase but not on-going protein translocation is required for tRNA import. We also show that import of tRNAs across the outer and inner membranes are coupled to each other. Taken together, these data support the 'alternate import model', which states that tRNA and protein import while mechanistically independent use the same translocation pores but not at the same time.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)
08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP) > NCCR RNA & Disease

Graduate School:

Graduate School for Cellular and Biomedical Sciences (GCB)

UniBE Contributor:

Shikha, Shikha; Huot, Jonathan; Schneider, André and Niemann, Moritz

Subjects:

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

ISSN:

0305-1048

Publisher:

Oxford University Press

Language:

English

Submitter:

Christina Schüpbach

Date Deposited:

30 Nov 2020 09:17

Last Modified:

12 Dec 2020 01:34

Publisher DOI:

10.1093/nar/gkaa1098

PubMed ID:

33231678

BORIS DOI:

10.7892/boris.148565

URI:

https://boris.unibe.ch/id/eprint/148565

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