Biochemical Characterization of the Apt1/Cdc50 Complex

Cryptococcus neoformans is an opportunist fungal pathogen lethal for patient with AIDS. Treatment options are limited and there is an urgent need for the discovery of anti-fungal drugs.

The membrane proteins Apt1 and Cdc50 from C. neoformans were identified as potential drug targets since it is involved in antifungal resistance and pathogen’s virulence.

Apt1 belongs to the P4-type ATPase family and together with Cdc50 proteins they are involved in the maintenance of phospholipid asymmetry in biological membranes.

In this project I plan to biochemically characterize Apt1/Cdc50 from C. neoformans, to identify inhibitors and functionally impaired mutants of this complex. These in vitro findings will be translated in vivo in C. neoformans cultures.

I plan to join the Laboratoire des Protéines et des Systèmes Membranaires (LPSM) at the CEA Paris-Saclay, a world-leading lab on P4-type ATPases, where I will set up protocols for the expression and purification of the Apt1/Cdc50 complex expressed in Saccharomyces cerevisiae.

Furthermore, thanks to my expertise in membrane protein reconstitution in liposomes and functional analysis, I will set up an assay to monitor in vitro phospholipid transport, an expertise still lacking at the LPSM. Using purified functional Apt1/Cdc50 complex we will screen a chemical library to identify inhibitors of this complex.

In parallel a structure-function study of the complex using directed mutagenesis will be conducted.

Finally, in vitro findings will be translated in vivo thanks to a collaboration with Pr Kronstad (University of British Columbia), a world expert on C. neoformans pathophysiology, where C. neoformans cultures are available.

This multidisciplinary project will benefit from the expertise of the host institution on P4-ATPases, my knowledge on membrane protein reconstitution in liposomes, and the experience of Pr Kronstad on in vivo study of C. neoformans. This would allow a 3-ways transfer of expertise.