Figure 1.

Overexpression of hCKIγ2 causes resistance to lysenin and decreased synthesis of SM. (A) CHO/hCKIγ2 cells and the parental CHO/C cells were incubated with or without lysenin (25 ng/ml) at 37°C for 1 h. After the treatment, the viability of the cells was determined. Values are means ± SD from triplicated experiments. (B) Lysate prepared from CHO/C and CHO/hCKIγ2 cells was subjected to Western blotting with anti-CKIγ2 antibody. Positions of molecular-weight markers are shown at the left of the panel. (C and D) CHO cell monolayers were incubated with [¹⁴C]serine (C) or [³H]sphingosine (D) at 37°C for 2 h. Metabolically labeled lipids of the cells were separated by TLC and analyzed. Left, images of radioactive lipids separated on TLC plates. PS, phosphatidylserine; PE, phosphatidylethanolamine; GlcCer, glucosylceramide; Cer, ceramide; GM3, GM3 ganglioside. Right, means ± SD from triplicated experiments.