FIG. 3.

(A) Western blot analysis of kidney, liver, and brain membrane proteins showing the absence of nSMase 1 protein in homozygous animals. wt, wild type. (B) nSMase activities of different organs. Different amounts of membrane protein extracts were used for the in vitro nSMase assay, and specific enzymatic activities were determined. The residual activity in kidney and heart from nsmase 1^−/− animals corresponds to the background of the assay, whereas liver and lung showed significant residual activities.