人肠乳糖酶-根皮苷水解酶前体的蛋白水解加工并非其在Madin Darby犬肾（MDCK）细胞中正确分选的先决条件。

Proteolytic processing of human intestinal lactase-phlorizin hydrolase precursor is not a prerequisite for correct sorting in Madin Darby canine kidney (MDCK) cells.

作者信息

Grünberg J, Luginbühl U, Sterchi E E

机构信息

Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Berne, Switzerland.

出版信息

FEBS Lett. 1992 Dec 21;314(3):224-8. doi: 10.1016/0014-5793(92)81476-3.

DOI:10.1016/0014-5793(92)81476-3

PMID:1468552

Abstract

Maturation of lactase-phlorizin hydrolase (LPH) (EC 3.2.1.23-62) requires proteolytic processing of precursor (pro-LPH) to mature microvillus membrane enzyme (m-LPH). Subcellular site and function of this processing are unknown. We studied the processing and sorting of human LPH expressed permanently in MDCK cells. LPH was inserted into the apical membrane and small amounts were found basolateral. Of the LPH immunoprecipitated from the apical membrane, 42% was in the mature, i.e. proteoytically processed form; on the basolateral membrane it was 20%. Thus, LPH-processing occurs after sorting and is not necessary for surface expression.

摘要

乳糖酶-根皮苷水解酶（LPH）（EC 3.2.1.23 - 62）的成熟需要将前体（前LPH）进行蛋白水解加工，以形成成熟的微绒毛膜酶（m-LPH）。这种加工的亚细胞位点和功能尚不清楚。我们研究了在MDCK细胞中永久表达的人LPH的加工和分选过程。LPH插入到顶端膜中，在基底外侧发现少量LPH。从顶端膜免疫沉淀的LPH中，42%为成熟形式，即经过蛋白水解加工的形式；在基底外侧膜上，这一比例为20%。因此，LPH的加工在分选之后发生，并且对于表面表达不是必需的。