Maturation of human lactase‐phlorizin hydrolase Proteolytic cleavage of precursor occurs after passage through the Golgi complex

FEBS Letters

Bähler, P.³  Oberholzer, T.²  Semenza, G.²  Lottaz, D.¹  Sterchi, E.E.¹ 

[1] Institute of Biochemistry and Molecular Biology, University of Berne, CH-3012 Berne, Switzerland;Department of Biochemistry, Swiss Federal Institute of Technology, ETH-Zentrum, CH-8092 Zürich, Switzerland;Department of Pediatrics, Faculty of Medicine, University of Berne, CH-3012 Berne, Switzerland

关键词: Lactase-phlorizin hydrolase;    Human;    Enterocyte;    Maturation;    Proteolytic processing;    Brefeldin A;    Caco-2 cell;    LPH;    lactase-phlorizin hydrolase;    SI;    sucrase—isomaltase;    α-1-AT;    α-1-antitrypsin;    BFA;    brefeldin A;    DOC;    sodium deoxycholate;    TGN;    trans-Golgi network;   

DOI  :  10.1016/0014-5793(92)81207-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Maturation of human intestinal lactase-phlorizin hydrolase (LPH) requires that a precursor (pro-LPH) be proteolytically processed to the mature microvillus membrane enzyme (m-LPH). The subcellular site of this processing is unknown. Using low-temperature experiments and brefeldin A (BFA), intracellular transport was blocked in intestinal epithelial cells. In Caco-2 cells incubated at 18°C pro-LPH was complex-glycosylated but not cleaved, while at 20°C small amounts of proteolytically processed LPH were observed. These data exclude a pre-Golgi proteolytic event. BFA completely blocked proteolytic maturation of LPH and lead to an aberrant form of pro-LPH in both Caco-2 cells and intestinal explants. Therefore, proteolytic processing of LPH is a post-Golgi event, occuring either in the trans-Golgi network, transport vesicles, or after insertion of pro-LPH into the microvillus membrane.

【 授权许可】

Unknown