Figure 2.

Psychosine preferentially accumulates in TWI lipid rafts. A, Comparison of total psychosine in raft fractions shows a significant increase in levels of the sphingolipid in TWI rafts at P3, P20, and P40. Data are expressed as a mean ± SE from two to four mice per time point and are shown in picomoles per gram. B, Mass spectrometric analysis of fractions prepared from P3 brains are amplified to more clearly convey differences at this age. These data are expressed in picomoles per gram and confirms that psychosine preferentially accumulates in rafts (fractions 4–5) at P3. C, Quantification of psychosine in raft, nonraft membrane, and pellet portions of the preparation indicate that membrane psychosine is preferentially accumulated in lipid rafts. Data are expressed as a percentage with respect to total psychosine. D, Analysis of psychosine accumulation in TWI sciatic nerves at P40 shows that, in peripheral nervous tissue, psychosine is accumulated in lipid rafts at levels comparable to those found in the brain. This figure is also expressed in picomoles per gram.