Quantitative Proteomic Analysis of Skeletal Muscle Detergent- Resistant Membranes in a Smith-Lemli-Opitz Syndrome Mouse

Abstract

Smith-Lemli-Opitz syndrome (SLOS) is an inborn error of metabolism affecting the last step of cholesterol biosynthesis. It is characterized by a deficiency of the enzyme 7dehydrocholesterol reductase and accumulation of 7-dehydrocholesterol (7DHC) in cells and body fluids. Given the similarities between 7DHC and cholesterol, 7DHC can be incorporated into cell membranes in lieu of cholesterol. Nevertheless, due to their structural differences and distinct affinity to other membrane components, this substitution alters membrane properties and one can expect to find abnormalities in membrane protein composition. In order to identify differences in membrane proteins that could facilitate our understanding of SLOS physiopathology, we isolated detergent-resistant membranes (DRMs) from the skeletal muscle of Dhcr7 T93M/T93M mice and C57/BL6 controls and performed comparative proteomic analysis using iTRAQ for peptide quantification. A total of 133 proteins were identified in the DRM fraction: 17 (13%) proteins demonstrated increased expression in SLOS mice, whereas, 21 (16%) showed decreased expression. Characterization of functional point of view and bioenergetics pathway and transmembrane transport responded to the major differences between the two groups of animals.