Research activity of the team « Glycobiology of olfaction » are delineated through 3 axes dealing with Mammalian Chemical Ecology (GDR CNRS MediatEC). One of the most important key-point in Mammalian life, reproduction, is mediated by exchange of chemical signals between partners, termed pheromones. Less than 20 pheromones were identified in mammals, despite their great potential of application for sustainable agriculture and breeding systems. Recently, environmental concerns, together with animal welfare concern have given a new impulsion in pheromone research, principally conducted by INRA (Institut National de Recherche Agronomique) and its private partner ALLICE in our laboratory.
Axis 1/ Role of Post-translational modifications in pheromone compounds reception
Besides pheromone identification, our work focuses on molecular mechanisms of pheromone reception in the nasal mucus. Among molecular players, Odorant-Binding Proteins (OBP) realize the first step of odors discrimination, by specifically binding to chemical signals. We have shown that this specificity is driven by phosphorylation and glycosylation, two post-translational modifications unexpected to modify secreted proteins. We are currently expressing the enzyme potentially involved in this modification (EOGT) in yeast cells, in order to study the modalities of its activity on recombinant OBPs (coll. Tony Lefebvre, UGSF). Recombinant EOGT will also be crystallized to solve its structure for the first time (coll. Vincent Villeret, UGSF). EOGT cellular trafficking is also followed by confocal microscopy (coll. François Foulquier, UGSF).
Axis 2/ Identification of Mammalian pheromones
The second research axis has the objective to optimize the reproduction management in ovine and caprine breeding systems, by using male pheromones as an alternative to hormonal synchronization of female cycle.
Axis 3/ Role of post-translational modifications in semen fertility
The third axis aims to characterize new phenotypic markers of sperm fertility in ruminants. Spermatozoa acquire fertility along a process that modifies their composition in lipids, carbohydrates, and proteins. This maturation process leads to fertility features such as mobility, and the ability to recognize and bind to oocyte. Different analyses are thus performed, with powerful proteomic (in coll. with MSAP lab), glycomic and lipidomic tools (PAGès platform), in order to identify phenotypic markers specific to fertility. Particular attention is paid to post-translational modifications of sperm proteome (phosphorylations, glycosylations, acetylations,…) and their involvement in conservation and fertility capacities of ovine and bovine semen.