Bettina Rieger

University of Münster | WWU · Molekulare Zellbiologie

Lima1 is an extensively studied prognostic marker of malignancy and is also considered to be a tumour suppressor, but its role in a developmental context of non-transformed cells is poorly understood. Here, we characterise the expression pattern and examined the function of Lima1 in mouse embryos and pluripotent stem cell lines. We identify that Li...

The classical view of oxidative phosphorylation is that a proton motive force (PMF) generated by the respiratory chain complexes fuels ATP synthesis via ATP synthase. Yet, under glycolytic conditions, ATP synthase in its reverse mode also can contribute to the PMF. Here, we dissected these two functions of ATP synthase and the role of its inhibitor...

During implantation, the murine embryo transitions from a "quiet" into an active metabolic/proliferative state, which kick-starts the growth and morphogenesis of the post-implantation conceptus. Such transition is also required for embryonic stem cells to be established from mouse blastocysts, but the factors regulating this process are poorly unde...

Our group has previously established a strategy utilizing fluorescence lifetime probes to image membrane protein supercomplex (SC) formation in situ. We showed that a probe at the interface between individual mitochondrial respiratory complexes exhibits a decreased fluorescence lifetime when a supercomplex is formed. This is caused by electrostatic...

The classical view of oxidative phosphorylation is that a proton motive force PMF generated by the respiratory chain complexes fuels ATP synthesis. Under glycolytic conditions, ATP synthase in its reverse mode also can contribute to the PMF. Here, we dissected the two functions of ATP synthase and the role of the inhibitory factor 1 (IF1) under dif...

Mitochondrial ATP synthase is the major producer of ATP in respiratory cells and maintains the mitochondrial membrane potential MMP in glycolytic cells. For these purposes, it works in forward (ATP synthesis) or reverse mode (ATP hydrolysis). Interestingly, these two modes are not necessarily antagonistic”. Recently, we found strong evidence that b...

•Mitochondrial F1FO ATP synthase is the key enzyme for mitochondrial bioenergetics. Dimeric F1FO-ATP synthase, is preferentially located at the edges of the cristae and its oligomerization state determines mitochondrial ultrastructure. The ATP synthase inhibitor protein IF1 modulates not only ATP synthase activity but also regulates both the struct...

A detailed description of pathophysiological effects that viruses exert on their host is still challenging. For the first time, we report a highly controllable viral expression model based on an iPS-cell line from a healthy human donor. The established viral model system enables a dose-dependent and highly localized RNA-virus expression in a fully...

Abstract Pseudomonas aeruginosa is a Gram‐negative bacterium of the proteobacteria class, and one of the most common causes of nosocomial infections. For example, it causes chronic pneumonia in cystic fibrosis patients. Patient sputum contains 2‐heptyl‐4‐hydroxyquinoline N‐oxide [HQNO] and Pseudomonas quorum sensing molecules such as the Pseudomona...

A new mitochondria-targeted probe MitoCLox was designed as a starting compound for a series of probes sensitive to cardiolipin (CL) peroxidation. Fluorescence microscopy reported selective accumulation of MitoCLox in mitochondria of diverse living cell cultures and its oxidation under stress conditions, particularly those known to cause a selective...

Cardiolipin (CL) is a multifunctional dimeric phospholipid that physically interacts with electron transport chain complexes I, III, and IV, and ATP synthase (complex V). The enzyme ALCAT1 catalyzes the conversion of cardiolipin by incorporating polyunsaturated fatty acids into cardiolipin. The resulting CL species are said to be more susceptible t...

F1FO ATP synthase is a key enzyme of mitochondrial energy metabolism which works in two directions. It is not known whether ATP synthase and ATPase function are correlated with different spatio-temporal organization of the enzyme. To analyze this, we have tracked and localized individual ATP synthase/ATPase molecules in situ by live cell microscopy...

Mitochondrial F1FO ATP synthase is the key enzyme to fuel the cell with essential ATP. Strong indications exist that the respiratory chain and the ATP synthase are physically separated within cristae. How static this organization is, is largely unknown. Here, we investigated the effect of substrate restriction on mitochondrial respiration and the s...

The assembly of respiratory complexes into macromolecular supercomplexes is currently a hot topic, especially in the context of newly available structural details. However, most work to date has been done with purified detergent-solubilized material and in situ confirmation is absent. We here set out to enable the recording of respiratory supercomp...

The cell is metabolically highly compartmentalized. Especially, mitochondria host many vital reactions in their different microcompartments. However, due to their small size, these microcompartments are not accessible by conventional microscopy. Here, we demonstrate that time-correlated single-photon counting (TCSPC) fluorescence lifetime-imaging m...

Ion-driven ATP synthesis by rotary F0F1 ATP-synthase powers aerobic life. Since Mitchell's seminal hypothesis, this synthesis has been discussed in terms of the proton-motive force between two bulk phases, each in equilibrium. In active mitochondria, a steady proton flow cycles between pumps and the distant ATP synthase. Here we determine the later...