1 Department of Ophthalmology, Faculty of Medicine, Université Laval, Quebec City, QC, G1S 4L8 Canada.
2 CUO-Recherche, Centre de Recherche du CHU de Québec, Hôpital du Saint-Sacrement, CHU de Québec, Quebec City, QC, G1S 4L8 Canada.
3 Departement of Chemistry, Faculty of Sciences, Université du Québec à Montréal, Montreal, QC, H2V 0B3 Canada.
4 Department of Chemistry and Biochemistry and Centre for NanoScience Research, Concordia University, Montreal, QC, H4B 1R6 Canada.
5 Departement of Biochemistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, N6A 5C1 Canada.
6 Laboratoire des Biomolécules, LBM, CNRS UMR 7203, Sorbonne Université, École Normale Supérieure, PSL University, Paris, 75 005 France.

Protein S100A10 participates in different cellular mechanisms and has different functions, especially at the membrane. Among those, it forms a ternary complex with annexin A2 and the C-terminal of AHNAK and then joins the dysferlin membrane repair complex. Together, they act as a platform enabling membrane repair. Both AHNAK and annexin A2 have been shown to have membrane binding properties. However, the membrane binding abilities of S100A10 are not clear. In this paper, we aimed to study the membrane binding of S100A10 in order to better understand its role in the cell membrane repair process. S100A10 was overexpressed by E. coli and purified by affinity chromatography. Using a Langmuir monolayer as a model membrane, the binding parameters and ellipsometric angles of the purified S100A10 were measured using surface tensiometry and ellipsometry, respectively. Phosphorus-31 solid-state nuclear magnetic resonance spectroscopy was also used to study the interaction of S100A10 with lipid bilayers. In the presence of a lipid monolayer, S100A10 preferentially interacts with unsaturated phospholipids. In addition, its behavior in the presence of a bilayer model suggests that S100A10 interacts more with the negatively charged polar head groups than the zwitterionic ones. This work offers new insights on the binding of S100A10 to different phospholipids and advances our understanding of the parameters influencing its membrane behavior.