Cornell R B, Nissley S M, Horwitz A F
J Cell Biol. 1980 Sep;86(3):820-4. doi: 10.1083/jcb.86.3.820.
The requirement of cholesterol for myoblast fusion has been linked to the primary step in the fusion process, calcium-dependent aggregation (recognition). Inhibition of cholesterol synthesis with 25-hydroxycholesterol or compactin in the absence of exogenous lipid dramatically inhibits calcium-mediated aggregation and concomitant fusion within several hours. Restimulating cholesterol synthesis or supplying exogenous cholesterol rapidly restores aggregation activity. Over this time period, however, the sterol:phospholipid ratio is unaltered, suggesting a local rather than a general membrane cholesterol requirement for the expression of aggregation activity. The aggregation response to a change in sterol availability occurs on a shorter time scale than that required to inhibit the synthesis of the protein(s) with aggregation activity; thus, the cholesterol-requiring step is posttranslational. We suggest that the assembly or maintenance of the aggregation activity depends on a continued local supply of cholesterol.
成肌细胞融合对胆固醇的需求与融合过程中的初级步骤，即钙依赖性聚集（识别）有关。在没有外源性脂质的情况下，用25-羟基胆固醇或洛伐他汀抑制胆固醇合成会在数小时内显著抑制钙介导的聚集以及随之而来的融合。重新刺激胆固醇合成或供应外源性胆固醇可迅速恢复聚集活性。然而，在此时间段内，固醇与磷脂的比例未发生改变，这表明聚集活性的表达需要局部而非整体的膜胆固醇。对固醇可用性变化的聚集反应发生的时间尺度比抑制具有聚集活性的蛋白质合成所需的时间尺度要短；因此，需要胆固醇的步骤是翻译后步骤。我们认为聚集活性的组装或维持依赖于胆固醇的持续局部供应。
