An HSP90 Cochaperone Ids2 Maintains the Stability of Mitochondrial DNA and ATP Synthase

Abstract Background Proteostasis unbalance and mitochondrial dysfunction are two hallmarks of aging. While the chaperone folds and activates its clients, it is the cochaperone that determines the specificity of the clients. Ids2 is an HSP90’s cochaperone controlling mitochondrial functions, but no in vivo clients of Ids2 have been reported yet. Results We performed a screen of the databases of HSP90 physical interactors, mitochondrial components, and mutants with respiratory defect, and identified Atp3, a subunit of the complex V ATP synthase, as a client of Ids2. Deletion of IDS2 destabilizes Atp3, and an α-helix at the middle region of Ids2 recruits Atp3 to the folding system. Shortage of Ids2 or Atp3 leads to the loss of mitochondrial DNA. The intermembrane space protease Yme1 is critical to maintaining the Atp3 protein level. Moreover, Ids2 is highly induced when cells carry out oxidative respiration. Conclusions These findings discover a cochaperone essentially for maintaining the stability of mitochondrial DNA and the proteostasis of the electron transport chain—crosstalk between two hallmarks of aging.

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Deletion of the natural inhibitory protein Inh1 in Ustilago maydis has no effect on the dimeric state of the F1FO-ATP synthase but increases the ATPase activity and reduces the stability

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/j.bbabio.2021.148429 ◽

2021 ◽

Vol 1862 (7) ◽

pp. 148429

Author(s):

Romero-Aguilar Lucero ◽

Esparza-Perusquía Mercedes ◽

Langner Thorsten ◽

García-Cruz Giovanni ◽

Feldbrügge Michael ◽

...

Keyword(s):

Atpase Activity ◽

Atp Synthase ◽

Ustilago Maydis ◽

Inhibitory Protein ◽

F1fo Atp Synthase ◽

The Stability

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Expression of the Saccharomyces cerevisiae Gene YME1 in the Petite-Negative Yeast Schizosaccharomyces pombe Converts It to Petite-Positive

Genetics ◽

10.1093/genetics/154.1.147 ◽

2000 ◽

Vol 154 (1) ◽

pp. 147-154 ◽

Cited By ~ 1

Author(s):

Douglas J Kominsky ◽

Peter E Thorsness

Keyword(s):

Saccharomyces Cerevisiae ◽

Mitochondrial Dna ◽

Schizosaccharomyces Pombe ◽

Atp Synthase ◽

Kluyveromyces Lactis ◽

Blot Hybridization ◽

Inner Mitochondrial Membrane ◽

Yeast Saccharomyces Cerevisiae ◽

Mitochondrial Atp Synthase ◽

Petite Negative Yeast

Abstract Organisms that can grow without mitochondrial DNA are referred to as “petite-positive” and those that are inviable in the absence of mitochondrial DNA are termed “petite-negative.” The petite-positive yeast Saccharomyces cerevisiae can be converted to a petite-negative yeast by inactivation of Yme1p, an ATP- and metal-dependent protease associated with the inner mitochondrial membrane. Suppression of this yme1 phenotype can occur by virtue of dominant mutations in the α- and γ-subunits of mitochondrial ATP synthase. These mutations are similar or identical to those occurring in the same subunits of the same enzyme that converts the petite-negative yeast Kluyveromyces lactis to petite-positive. Expression of YME1 in the petite-negative yeast Schizosaccharomyces pombe converts this yeast to petite-positive. No sequence closely related to YME1 was found by DNA-blot hybridization to S. pombe or K. lactis genomic DNA, and no antigenically related proteins were found in mitochondrial extracts of S. pombe probed with antisera directed against Yme1p. Mutations that block the formation of the F1 component of mitochondrial ATP synthase are also petite-negative. Thus, the F1 complex has an essential activity in cells lacking mitochondrial DNA and Yme1p can mediate that activity, even in heterologous systems.

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Case Report: Identification of a Novel Variant (m.8909T>C) of Human Mitochondrial ATP6 Gene and Its Functional Consequences on Yeast ATP Synthase

Life ◽

10.3390/life10090215 ◽

2020 ◽

Vol 10 (9) ◽

pp. 215

Author(s):

Qiuju Ding ◽

Róża Kucharczyk ◽

Weiwei Zhao ◽

Alain Dautant ◽

Shutian Xu ◽

...

Keyword(s):

Mitochondrial Dna ◽

Atp Synthase ◽

Atp Synthesis ◽

Single Individual ◽

Loss Of Function ◽

Mtdna Mutations ◽

Atp6 Gene ◽

Novel Variant ◽

Functional Consequences ◽

Mtdna Variants

With the advent of next generation sequencing, the list of mitochondrial DNA (mtDNA) mutations identified in patients rapidly and continuously expands. They are frequently found in a limited number of cases, sometimes a single individual (as with the case herein reported) and in heterogeneous genetic backgrounds (heteroplasmy), which makes it difficult to conclude about their pathogenicity and functional consequences. As an organism amenable to mitochondrial DNA manipulation, able to survive by fermentation to loss-of-function mtDNA mutations, and where heteroplasmy is unstable, Saccharomyces cerevisiae is an excellent model for investigating novel human mtDNA variants, in isolation and in a controlled genetic context. We herein report the identification of a novel variant in mitochondrial ATP6 gene, m.8909T>C. It was found in combination with the well-known pathogenic m.3243A>G mutation in mt-tRNALeu. We show that an equivalent of the m.8909T>C mutation compromises yeast adenosine tri-phosphate (ATP) synthase assembly/stability and reduces the rate of mitochondrial ATP synthesis by 20–30% compared to wild type yeast. Other previously reported ATP6 mutations with a well-established pathogenicity (like m.8993T>C and m.9176T>C) were shown to have similar effects on yeast ATP synthase. It can be inferred that alone the m.8909T>C variant has the potential to compromise human health.

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Sequence analysis of the ATP synthase of subunits (ATP8 and ATP6) genes of mitochondrial DNA genome from Ailuropoda melanoleuca

Mitochondrial DNA Part B ◽

10.1080/23802359.2018.1424574 ◽

2018 ◽

Vol 3 (2) ◽

pp. 1092-1093

Author(s):

Yaodong Hu ◽

Huizhong Pang ◽

Shanshan Ling ◽

Rongping Wei ◽

Yun Zhu ◽

...

Keyword(s):

Mitochondrial Dna ◽

Sequence Analysis ◽

Atp Synthase ◽

Ailuropoda Melanoleuca

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RAD51C/XRCC3 Facilitates Mitochondrial DNA Replication and Maintains Integrity of the Mitochondrial Genome

Molecular and Cellular Biology ◽

10.1128/mcb.00489-17 ◽

2017 ◽

Vol 38 (3) ◽

Cited By ~ 6

Author(s):

Anup Mishra ◽

Sneha Saxena ◽

Anjali Kaushal ◽

Ganesh Nagaraju

Keyword(s):

Mitochondrial Dna ◽

Mitochondrial Genome ◽

Hot Spot ◽

Neurological Diseases ◽

Replication Stress ◽

Genome Maintenance ◽

Mtdna Mutation ◽

Direct Role ◽

D Loop ◽

The Stability

ABSTRACT Mechanisms underlying mitochondrial genome maintenance have recently gained wide attention, as mutations in mitochondrial DNA (mtDNA) lead to inherited muscular and neurological diseases, which are linked to aging and cancer. It was previously reported that human RAD51, RAD51C, and XRCC3 localize to mitochondria upon oxidative stress and are required for the maintenance of mtDNA stability. Since RAD51 and RAD51 paralogs are spontaneously imported into mitochondria, their precise role in mtDNA maintenance under unperturbed conditions remains elusive. Here, we show that RAD51C/XRCC3 is an additional component of the mitochondrial nucleoid having nucleus-independent roles in mtDNA maintenance. RAD51C/XRCC3 localizes to the mtDNA regulatory regions in the D-loop along with the mitochondrial polymerase POLG, and this recruitment is dependent upon Twinkle helicase. Moreover, upon replication stress, RAD51C and XRCC3 are further enriched at the mtDNA mutation hot spot region D310. Notably, the absence of RAD51C/XRCC3 affects the stability of POLG on mtDNA. As a consequence, RAD51C/XRCC3-deficient cells exhibit reduced mtDNA synthesis and increased lesions in the mitochondrial genome, leading to overall unhealthy mitochondria. Together, these findings lead to the proposal of a mechanism for a direct role of RAD51C/XRCC3 in maintaining mtDNA integrity under replication stress conditions.

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