Johnson L M, Bankaitis V A, Emr S D
Cell. 1987 Mar 13;48(5):875-85. doi: 10.1016/0092-8674(87)90084-5.
We have mapped a sequence determinant in the vacuolar glycoprotein carboxypeptidase Y (CPY) that directs intracellular sorting of this enzyme. Through the study of hybrid proteins, consisting of amino-terminal segments of CPY fused to the secretory enzyme invertase, we have found that the N-terminal 50 amino acids of CPY are sufficient to direct delivery of a CPY-Inv hybrid protein to the yeast vacuole. Our data suggest that this 50 amino acid segment of CPY contains two distinct functional domains; an N-terminal signal peptide followed by a segment of 30 amino acids that contains the vacuolar sorting signal. Deletion of this putative vacuole sorting signal from an otherwise wild-type CPY protein leads to missorting of CPY. Furthermore, examination of the Asn-linked oligosaccharides present on CPY and CPY-Inv hybrid proteins suggests that an additional determinant in CPY specifies the extent to which these proteins are glycosylated in the Golgi complex.
我们已经绘制出液泡糖蛋白羧肽酶Y（CPY）中一个序列决定簇，该决定簇指导这种酶的细胞内分选。通过对由CPY的氨基末端片段与分泌酶转化酶融合而成的杂合蛋白的研究，我们发现CPY的N末端50个氨基酸足以将CPY-Inv杂合蛋白递送至酵母液泡。我们的数据表明，CPY的这50个氨基酸片段包含两个不同的功能结构域；一个N末端信号肽，其后是一段30个氨基酸的片段，该片段包含液泡分选信号。从原本野生型的CPY蛋白中删除这个假定的液泡分选信号会导致CPY分选错误。此外，对CPY和CPY-Inv杂合蛋白上存在的N-连接寡糖的检测表明，CPY中的另一个决定簇决定了这些蛋白在高尔基体中糖基化的程度。
