Arthur Charles-Orszag

Research Interests

Archaea are the third domain of life on Earth. They are present in most habitats, from the most extreme environments to the human gut, and it was recently proposed that eukaryotes originated from within the archaeal domain. However, very little is known about their cell biology.

A major barrier to the advancement of archaeal cell biology has been the inability to image model species, which are all extremophiles, in physiological conditions. For example, the model crenarchaeon Sulfolobus acidocaldarius optimally grows at 76°C and pH 2. In the lab, we develop new tools to allow quantitative imaging of extremophiles. We also use biochemical, structural, genetic and bioinformatic approaches to study fundamental aspects of archaeal cell biology in various archaeal models. 

One of the most puzzling events in cellular evolution is eukaryogenesis. Thought to have appeared ~2.2 Gya, the first eukaryotes resulted from the association between an archaeon and a bacterium, with the latter giving rise to modern mitochondria. However, this model is still incomplete, and the cellular and molecular aspects of eukaryogenesis are still unclear. In particular, key questions remain regarding the cellular complexity of the first eukaryotic common ancestor. Our lack of understanding of the basic cell biology of archaea is a major hurdle to answering these questions.