Silve S, Volland C, Hinnen A, Haguenauer-Tsapis R
Laboratoire de Biochimie des Porphyrines, Institut Jacques Monod, Université Paris VII, France.
Biochimie. 1990 Feb-Mar;72(2-3):103-14. doi: 10.1016/0300-9084(90)90135-4.
The repressible Saccharomyces cerevisiae acid phosphatase (APase) coded by the PHO5 gene is a cell wall protein that follows the yeast secretory pathway. We had previously described the in vivo fate of a multicopy plasmid-encoded modified protein, lacking 15 out of 17 signal peptide amino acids. This modified protein accumulates mainly within the cell as an inactive unglycosylated form. However 30% of this precursor is translocated, glycosylated and dispatched to the cell wall. We establish, in the present report, that this phenomenon did not result from an overproduction of the plasmid encoded protein, since it was also observed in a normal single copy situation. The secretion persisted after a deletion including the single hydrophobic segment present in the N-terminus of the mature protein. The entry of both wild type and mutant APase into the ER was inhibited in sec62 mutants suggesting that the SEC62 gene product would not be implicated in signal peptide recognition.
由PHO5基因编码的可阻遏的酿酒酵母酸性磷酸酶（APase）是一种遵循酵母分泌途径的细胞壁蛋白。我们之前描述过一种多拷贝质粒编码的修饰蛋白在体内的命运，该蛋白的17个信号肽氨基酸中有15个缺失。这种修饰蛋白主要以无活性的未糖基化形式在细胞内积累。然而，这种前体蛋白的30%会被转运、糖基化并分泌到细胞壁。在本报告中我们确定，这种现象并非由质粒编码蛋白的过量产生导致，因为在正常单拷贝情况下也观察到了这种现象。在缺失了成熟蛋白N端存在的单个疏水片段后，分泌仍持续存在。sec62突变体中野生型和突变型APase进入内质网均受到抑制，这表明SEC62基因产物与信号肽识别无关。
