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Trypanosomal Pam18/Pam16 and maxicircle replication – MaRF11 SILAC RNAi

ABSTRACT: Protein import and genome replication are essential processes for mitochondrial biogenesis and propagation. The J-domain proteins Pam16 and Pam18 regulate the presequence translocase of the mitochondrial inner membrane. In the protozoan Trypanosoma brucei, their counterparts are TbPam16 and TbPam18, which are essential for the procyclic form of the parasite, though not involved in mitochondrial protein import. Here, we show that during evolution, the two proteins have been repurposed to regulate the replication of maxicircles within the intricate kDNA network, the most complex mitochondrial genome known. TbPam18 and TbPam16 have inactive J-domains suggesting a function independent of heat shock proteins. However, their single transmembrane domain is essential for function. Pulldown of TbPam16 identifies a putative client protein, termed MaRF11, the depletion of which causes the selective loss of maxicircles, akin to the effects observed for TbPam18 and TbPam16. The level of MaRF11 is controlled by the mitochondrial proteasome. Thus, we propose a model for a membrane-bound regulatory circuit that controls maxicircle replication in response to an unknown nuclear signal. This model posits that MaRF11 directly mediates maxicircle replication, that its activity is regulated by the mitochondrial proteasome that its level is controlled by proteasomal digested that it is protected from degradation by binding to the TbPam18/TbPam16 dimer.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Trypanosoma Brucei

SUBMITTER: Julian Bender

LAB HEAD: Bettina Warscheid

PROVIDER: PXD053251 | Pride | 2024-07-20

REPOSITORIES: Pride

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			Action	DRS
	QEplus040245.raw	Raw
	QEplus040246.raw	Raw
	QEplus040248.raw	Raw
	QEplus040249.raw	Raw
	txt_MaRF11RNAi.zip	Other

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Trypanosomal Pam18/Pam16 and maxicircle replication – TbPam16 CoIPs

Project description:Protein import and genome replication are essential processes for mitochondrial biogenesis and propagation. The J-domain proteins Pam16 and Pam18 regulate the presequence translocase of the mitochondrial inner membrane. In the protozoan Trypanosoma brucei, their counterparts are TbPam16 and TbPam18, which are essential for the procyclic form of the parasite, though not involved in mitochondrial protein import. Here, we show that during evolution, the two proteins have been repurposed to regulate the replication of maxicircles within the intricate kDNA network, the most complex mitochondrial genome known. TbPam18 and TbPam16 have inactive J-domains suggesting a function independent of heat shock proteins. However, their single transmembrane domain is essential for function. Pulldown of TbPam16 identifies a putative client protein, termed MaRF11, the depletion of which causes the selective loss of maxicircles, akin to the effects observed for TbPam18 and TbPam16. The level of MaRF11 is controlled by the mitochondrial proteasome. Thus, we propose a model for a membrane-bound regulatory circuit that controls maxicircle replication in response to an unknown nuclear signal. This model posits that MaRF11 directly mediates maxicircle replication, that its activity is regulated by the mitochondrial proteasome that its level is controlled by proteasomal digested that it is protected from degradation by binding to the TbPam18/TbPam16 dimer.

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