Semenova S B, Kiselev K I, Mozhaeva G N
Institute of Cytology of the Russian Acad. Sci., St. Petersburg, Russia.
Ross Fiziol Zh Im I M Sechenova. 1998 May-Jun;84(5-6):417-25.
Using patch-clamp technique we have shown that the plasma membrane of mouse macrophages contains calcium channels that are activated by inositol (1, 4, 5)-trisphosphate (IP3) and blocked by heparine. Their conductivity properties strongly differentiate them from IP3-activated channels of endoplasmic reticulum, but make it possible to include them to the ICRAC family. By the other hand, properties of the IP3 receptor (IP3R) of our channels are similar to those of endoplasmic IP3R. Basing on these data we suggest that IP3R could be located out of the plasma membrane, and by some conformational changes transduces the signal to the high selective Ca2+ channel in the plasma membrane. This model well conforms with the known in the literature "coupling model" of calcium signalling [1].
运用膜片钳技术，我们已证明小鼠巨噬细胞的质膜含有钙通道，这些通道可被肌醇（1,4,5）-三磷酸（IP3）激活，并被肝素阻断。它们的电导率特性使其与内质网的IP3激活通道有很大区别，但有可能将它们归入ICRAC家族。另一方面，我们通道的IP3受体（IP3R）特性与内质网IP3R的特性相似。基于这些数据，我们认为IP3R可能位于质膜外，并通过一些构象变化将信号传递给质膜中的高选择性Ca2+通道。该模型与文献中已知的钙信号“偶联模型”[1]非常吻合。
