Glucokinase regulatory protein is essential for the proper subcellular localisation of liver glucokinase

FEBS Letters

Veiga-da-Cunha, Maria¹  Ferrer, Juan C.²  de la Iglesia, Núria²  Van Schaftingen, Emile¹  Guinovart, Joan J.² 

[1] Laboratory of Physiological Chemistry, Christian de Duve Institute of Cellular Pathology and Université Catholique de Louvain, B-1200 Brussels, Belgium;Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Martí i Franquès, 1, E-08028 Barcelona, Spain

关键词: Glucokinase regulatory protein;    Protein-protein interaction;    Fluorescence microscopy;    GK;    glucokinase;    GKRP;    glucokinase regulatory protein;    GFP;    green fluorescent protein;    BFP;    blue fluorescent protein;   

DOI  :  10.1016/S0014-5793(99)00971-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Glucokinase (GK), a key enzyme in the glucose homeostatic responses of the liver, changes its intracellular localisation depending on the metabolic status of the cell. Rat liver GK and Xenopus laevis GK, fused to the green fluorescent protein (GFP), concentrated in the nucleus of cultured rat hepatocytes at low glucose and translocated to the cytoplasm at high glucose. Three mutant forms of Xenopus GK with reduced affinity for GK regulatory protein (GKRP) did not concentrate in the hepatocyte nuclei, even at low glucose. In COS-1 and HeLa cells, a blue fluorescent protein (BFP)-tagged version of rat liver GK was only able to accumulate in the nucleus when it was co-expressed with GKRP-GFP. At low glucose, both proteins concentrated in the nuclear compartment and at high glucose, BFP-GK translocated to the cytosol while GKRP-GFP remained in the nucleus. These findings indicate that the presence of and binding to GKRP are necessary and sufficient for the proper intracellular localisation of GK and directly involve GKRP in the control of the GK subcellular distribution.

【 授权许可】

Unknown