Research

Cells are the basic unit of life and have acquired in evolution not only the ability to proliferate but also to take decisions, protect themselves against a broad variety of stresses or pathogens, memorize information about their past experience and adapt their shape and activities to environmental cues and conditions. We are using different yeast species to study how Eukaryotes carry out these different functions and how these activities contribute to cellular diversity, speciation and aging. We focus particularly on the role of two universal processes in Eukaryotes, namely cell division (particularly asymmetric cell division) and the sexual cycle (focusing on mating).

Mitotic cell division and mating are probably the most ancestral and precisely orchestrated morphogenetic events in Eukaryotes. Their detailed analysis may therefore reveal basic principles of eukaryotic organization. Cell division not only drives cellular proliferation and vegetative reproduction but is also the origin of much cellular diversity. Through asymmetric segregation of cell fate determinants, memory engrams, aging factors and pathogenic elements, cell division drives processes as distinct as aging and renewal, individualization and specialization of single cells, the generation of complex cellular communities as well as the escape from infectious agents. Uniquely, the sexual cycle, builds on inter-cellular communication to drive gene flow as well as speciation. Our research currently focuses on five topics:

1. The role of the microtubule cytoskeleton in the proper positioning and orientation of the nucleus during asymmetric cell division and in the fusion of partner nuclei during mating.
2. The dynamics of the nucleus and the nuclear envelope during mitosis and how it supports the symmetric segregation of the chromosomes while promoting the asymmetric partition of aging factors.
3. Nature and function of diffusion barriers, which compartmentalize the internal membrane systems of the cell (endoplasmic reticulum, nuclear envelope, mitochondrial membranes) into aging and rejuvenating domains.
4. The cellular computing and decision making machinery through which cells decide to mate, choose their partner or learn to avoid suboptimal ones.
5. The existence of innate immunity mechanisms allowing cells to distinguish non-chromosomal from chromosomal DNA to protect themselves against exogenous genetic noise.