Christian Salesse

Christian Salesse is a researcher at the CHU de Québec – Université Laval Research Center and full professor at the department of ophthalmology-ORL-CCF of Université Laval. He obtained his doctorate degree in biophysics from the Université du Québec à Trois-Rivières (UQTR) and was a postdoctoral fellow at the Johannes Gutenberg Universität in Mainz, Germany. He was then a professor at UQTR for 14 years until he moved to Université Laval in 2002. He has been an adjunct professor at Jilin University in Changchun, China, since 1995. He was a research fellow from the FRQS from the Junior to the National level. He has been an invited professor at several universities in France as well as in Portugal. In addition, he has been directeur de recherche associé at the CNRS and chercheur-boursier of the INSERM in France.

Membrane binding of proteins involved in visual phototransduction and visual cycle

The first event of vision consists of the absorption of light by the visual pigment of retinal photoreceptors. Visual phototransduction is a very fast process, which involves numerous proteins. The high speed of phototransduction is favored by the confinement of visual proteins through their attachment to photoreceptor membranes, as well as by the very high fluidity of these membranes, which contain lipids bearing highly polyunsaturated fatty acyl chains. It is a particular derivative of vitamin A (11-cis retinal) that allows light absorption by the visual pigment, resulting in its isomerization into all-trans retinal. The visual cycle allows regenerating 11-cis retinal through the action of several proteins located in both the photoreceptors and the retinal pigment epithelium. Our research work aims to determine the mechanism underlying the membrane binding of the proteins involved in visual phototransduction and the visual cycle. We thus overexpress these proteins, fused with various solubilization/purification tags in different expression vectors. We have thus developed particular expertise in the expression and purification of proteins. Membrane binding measurements are then performed with these proteins using different approaches that we have either developed ourselves or in collaboration with colleagues.

Enzymatic activity of proteins of the visual cycle and their mutations leading to photoreceptor degeneration

The eye is the organ where the largest number of mutations leading to hereditary diseases can be found. Mutations have thus been found in almost all proteins involved in both visual phototransduction and the visual cycle, leading to photoreceptor degeneration and blindness. Our research work aims to understand the impact of these mutations on the enzymatic activity of some of the proteins involved in the visual cycle. We have thus developed methods to characterize the enzymatic activity of these enzymes as well as to express and purify these mutated enzymes.