Umbach J A, Zinsmaier K E, Eberle K K, Buchner E, Benzer S, Gundersen C B
Department of Molecular and Medical Pharmacology School of Medicine, University of California, Los Angeles 90024.
Neuron. 1994 Oct;13(4):899-907. doi: 10.1016/0896-6273(94)90255-0.
Cysteine string proteins are synapse-specific proteins. In Drosophila, csp deletion mutants exhibit temperature-sensitive paralysis and early death. Here, we report that neuromuscular transmission is impaired presynaptically in these csp mutant larvae. At 22 degrees C, evoked transmitter release is depressed relative to wild type and rescued controls, and high frequency stimulation of the nerve leads to sporadic failures. At 30 degrees C, stimulus-evoked responses decline gradually before failing completely. When the temperature is returned to 22 degrees C, evoked responses recover. Spontaneous release events persist at both 22 degrees C and 30 degrees C. Since nerve conduction and postsynaptic sensitivity are unaffected, these data indicate that csp mutations disrupt depolarization-secretion coupling. This disruption explains the cellular basis of the temperature-sensitive paralysis of these organisms.
半胱氨酸串珠蛋白是突触特异性蛋白。在果蝇中，csp缺失突变体表现出温度敏感型麻痹和早期死亡。在此，我们报告这些csp突变体幼虫的神经肌肉传递在突触前受损。在22摄氏度时，与野生型和挽救对照相比，诱发的递质释放受到抑制，并且对神经的高频刺激会导致零星的传递失败。在30摄氏度时，刺激诱发的反应在完全失败之前逐渐下降。当温度恢复到22摄氏度时，诱发反应恢复。在22摄氏度和30摄氏度时，自发释放事件均持续存在。由于神经传导和突触后敏感性不受影响，这些数据表明csp突变破坏了去极化-分泌偶联。这种破坏解释了这些生物体温度敏感型麻痹的细胞基础。
