Helen Cooper

Helen Cooper
Åbo Akademi University · Department of Biochemistry

PhD

About

22
Publications
3,542
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,199
Citations
Introduction
I am currently working on mitochondrial nucleoids and lipid biochemistry
Skills and Expertise

Publications

Publications (22)
Article
In the diagnostic work-up of a newborn infant with a metabolic crisis, lethal multiorgan failure on day six of life, and increased excretion of 3-methylglutaconic acid, we found using whole genome sequencing a homozygous SERAC1-mutation indicating MEGDHEL syndrome (3-methylglutaconic aciduria with deafness-dystonia, hepatopathy, encephalopathy, and...
Article
Full-text available
De novo mutations in ATAD3A (ATPase family AAA-domain containing protein 3A) were recently found to cause a neurological syndrome with developmental delay, hypotonia, spasticity, optic atrophy, axonal neuropathy, and hypertrophic cardiomyopathy. Using whole-exome sequencing, we identified a dominantly inherited heterozygous variant c.1064G > A (p.G...
Article
Full-text available
Increased production of reactive oxygen species (ROS) has long been considered a cause of aging. However, recent studies have implicated ROS as essential secondary messengers. Here we show that the site of ROS production significantly contributes to their apparent dual nature. We report that ROS increase with age as mitochondrial function deteriora...
Article
Full-text available
The helicase Twinkle is indispensable for mtDNA replication in nucleoids. Previously, we showed that Twinkle is tightly membrane-associated even in the absence of mtDNA, which suggests that Twinkle is part of a membrane-attached replication platform. Here we show that this platform is a cholesterol-rich membrane structure. We fractionated mitochond...
Article
Full-text available
Mitochondrial ribosomes and translation factors co-purify with mitochondrial nucleoids of human cells, based on affinity protein purification of tagged mitochondrial DNA binding proteins. Among the most frequently identified proteins were ATAD3 and prohibitin, which have been identified previously as nucleoid components, using a variety of methods....
Article
Full-text available
The bacterial homologue of C4orf14, YqeH, has been linked to assembly of the small ribosomal subunit. Here, recombinant C4orf14 isolated from human cells, co-purified with the small, 28S subunit of the mitochondrial ribosome and the endogenous protein co-fractionated with the 28S subunit in sucrose gradients. Gene silencing of C4orf14 specifically...
Data
Full-text available
FLAG-tagged mSIRT3 variants M1, M2 and M3 expressed in 3T3 cells. (A) Similar amounts of total cell and crude mitochondrial lysates from cells expressing mSirt3 variants M1-3 from plasmids with endogenous Kozak sequences 5′ of the respective ATG start codons. (B) Samples from cells expressing mSirt3 variants M1-3 from plasmids with consensus Kozak...
Article
Full-text available
Mammals have seven NAD-dependent protein deacetylases. These proteins, called sirtuins, are homologous to yeast Sir2, and are emerging as important regulators of lifespan and intermediary metabolism. Three mammalian sirtuins, SIRT3-5 are mitochondrial. Sirtuins are highly conserved between species, yet mouse SIRT3 was reported to be markedly shorte...
Article
Full-text available
Mutations in the mitochondrial helicase Twinkle underlie autosomal dominant progressive external ophthalmoplegia (PEO), as well as recessively inherited infantile-onset spinocerebellar ataxia and rare forms of mitochondrial DNA (mtDNA) depletion syndrome. Familial PEO is typically associated with the occurrence of multiple mtDNA deletions, but the...
Article
Full-text available
Infantile-onset spinocerebellar ataxia (IOSCA) is a severe neurodegenerative disorder caused by the recessive mutation in PEO1, leading to an Y508C change in the mitochondrial helicase Twinkle, in its helicase domain. However, no mitochondrial dysfunction has been found in this disease. We studied here the consequences of IOSCA for the central nerv...
Article
Full-text available
It has recently been suggested that perhaps as many as 20% of all mitochondrial proteins are regulated through lysine acetylation while SIRT3 has been implicated as an important mitochondrial protein deacetylase. It is therefore of crucial importance that the mitochondrial localization of potential protein deacetylases is unambiguously established....
Article
Full-text available
The human gene POLG encodes the catalytic subunit of mitochondrial DNA polymerase, but its precise roles in mtDNA metabolism in vivo have not hitherto been documented. By expressing POLG fusion proteins in cultured human cells, we show that the enzyme is targeted to mitochondria, where the Myc epitope-tagged POLG is catalytically active as a DNA po...

Network

Cited By

Projects

Project (1)