Salminen A, Novick P J
Cell. 1987 May 22;49(4):527-38. doi: 10.1016/0092-8674(87)90455-7.
Secretion is blocked at the post-Golgi stage within 5 min of a shift of sec4-8 cells from 25 degrees C to 37 degrees C. Analysis of SEC4 predicts a protein product of 23.5 kd molecular weight that shares 32% homology with ras proteins and is essential for growth. The regions of best homology are those involved in the binding and hydrolysis of GTP. Duplication of SEC4 suppresses post-Golgi-blocked mutations in three sec genes. These mutations are lethal when combined with sec4-8 at 25 degrees C. Mutations that block elsewhere on the pathway are not suppressed by the SEC4 duplication and are not lethal when combined with sec4-8. We propose that the SEC4 product is a GTP-binding protein that plays an essential role in controlling a late stage of the secretory pathway.
当sec4 - 8细胞从25摄氏度转移至37摄氏度后5分钟内，分泌在高尔基体后阶段被阻断。对SEC4的分析预测其蛋白质产物分子量为23.5千道尔顿，与ras蛋白有32%的同源性，且对生长至关重要。同源性最高的区域是参与GTP结合和水解的区域。SEC4的复制可抑制三个sec基因中高尔基体后阻断的突变。这些突变在25摄氏度与sec4 - 8结合时是致死的。在该途径其他位置阻断的突变不会被SEC4复制所抑制，且与sec4 - 8结合时也不会致死。我们提出SEC4产物是一种GTP结合蛋白，在控制分泌途径的后期阶段发挥着重要作用。
