Guanosine nuceleotides modulate the inhibitory effect of Brefeldin A on protein secretion

FEBS Letters

Schulz, Irene¹  Zeuzem, Stefan¹  Zimmermann, Petra¹ 

[1] Max-Planck-Institut für Biophysik, Kennedyallee 70, 6000 Frankfurt a.M. 70, Germany

关键词: Brefeldin A;    Protein synthesis;    Protein secretion;    Pulse-chase experiment;    Small molecular weight GTP-binding protein;    Guanosine nucleotide;   

DOI  :  10.1016/0014-5793(91)81021-Y

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Brefeldin A (BFA) causes rapid redistribution of Golgi proteins into the endoplasmic reticulum (ER), leaving no definable Golgi-apparatus, and blocks transport or proteins from the ER to distal secretory compartments of the cell. Using pulse-chase experiments the present study shows that BFA (1 μ/ml) inhibits basal and CCK-stimulated protein secretion in isolated pancreatic acinar cells by 65 ± 6% and 84 ± 5%, respectively. In isolated permeabilized cells higher concentrations of BFA (30 μg/ml) were necessary to obtain inhibition of protein secretion. In parallel experiments protein secretion was stimulated by GTP (1 mM). BFA had no inhibitory effect on protein secretion in the presence of GTP, indicating that BFA might act on a GTP-binding protein. Investigating the effect of BFA on small molecular weight GTP-binding proteins we observed that [α-³²P]GTP binding to a 21 kDa protein in a subcellular fraction enriched in ER was increased in the presence of BFA. We conclude that this 21 kDa and possibly also other GTP-binding proteins may be the molecular target of Brefeldin A in pancreatic acinar cells.

【 授权许可】

Unknown