Santini M T, Indovina P L, Hausman R E
Laboratorio di Fisica, INFN, Sezione Sanità, Roma, Italy.
Biochim Biophys Acta. 1988 Mar 3;938(3):489-92. doi: 10.1016/0005-2736(88)90147-2.
Myogenic differentiation in vitro involves at least three events at the cell surface: binding of prostaglandin to cells, cell-cell adhesion, and fusion of the myoblast membranes into syncytia. Previous work has suggested that binding of prostaglandin is causal to the change in cell-cell adhesion and that both are accompanied by a characteristic reorganization of the myoblast membrane detected as a transient increase in membrane order by electron paramagnetic resonance. We show here that this membrane order change, which reaches a maximum at 38 h of development in vitro, was the last membrane order change before bilayer fusion which begins several hours later. This membrane order change, which accompanies the change in cell-cell adhesion, was dependent on the availability of prostaglandin. In myoblasts maintained in indomethacin, where further differentiation is known to be blocked at the prostaglandin binding step, the membrane order change did not occur. However, if myoblasts are provided with exogenous prostaglandin, the membrane order change occurred and differentiation proceeded. The results indicate that the basis of the membrane order change was the reorganization of myoblast membranes to allow increased adhesion and prepare the membrane for bilayer fusion. They also demonstrate that, like the increase in myoblast adhesion, the membrane order change was dependent on prostaglandin being available to bind to its receptor.
前列腺素与细胞的结合、细胞间黏附以及成肌细胞膜融合形成多核细胞。先前的研究表明，前列腺素的结合是细胞间黏附变化的原因，并且两者都伴随着成肌细胞膜的特征性重组，通过电子顺磁共振检测为膜有序性的短暂增加。我们在此表明，这种膜有序性变化在体外发育38小时时达到最大值，是数小时后开始的双层膜融合之前的最后一次膜有序性变化。这种伴随细胞间黏附变化的膜有序性变化取决于前列腺素的可用性。在维持于吲哚美辛中的成肌细胞中，已知进一步的分化在前列腺素结合步骤被阻断，膜有序性变化未发生。然而，如果给成肌细胞提供外源性前列腺素，膜有序性变化就会发生且分化继续进行。结果表明，膜有序性变化的基础是成肌细胞膜的重组，以增加黏附并为双层膜融合准备膜。它们还证明，与成肌细胞黏附的增加一样，膜有序性变化取决于前列腺素能够与其受体结合。
