Figure 1.

Dermal skin fibroblasts from patients with LS show reduced internalization of the lysosomal enzyme ASB. (A) Cell lysates of dermal skin fibroblasts from six patients with LS (LS 1 to LS 6) and three healthy individuals (Con 1 to Con 3) were subjected to SDS–PAGE, and immunoblotting with an anti-OCRL antibody was performed. Equal protein loading was confirmed by probing with an anti-GAPDH antibody. OCRL mutations in patients LS 1 to LS 6 were identified by routine genetic testing in our lab and are indicated for each cell line. (B) Control and LS fibroblasts were incubated with [¹²⁵I]ASB for 3h as described in Materials and Methods. Intracellular radioactivity was determined in a γ-counter and normalized to the protein content. The amount of internalized [¹²⁵I]ASB in LS fibroblasts is expressed as percentage of control cells. Each bar is the mean ± SD of at least five independent experiments. ***P < 0.001 (two-tailed Student's t-test).