Substitution of conserved tyrosine residues in helix 4 (Y143) and 7 (Y293) affects the activity, but not IAPS‐forskolin binding, of the glucose transporter GLUT4

FEBS Letters

Joost, Hans G.²  Wandel, Sonja²  Schürmann, Annette²  Shanahan, Michael F.¹  Becker, Walter²  Summers, Scott A.¹ 

[1] Department of Physiology, School of Medicine, University of Southern Illinois at Carbondale, Carbondale, IL 62901, USA;Institut für Pharmakologie und Toxikologie der RWTH Aachen, Wendlingweg 2, D-52057 Aachen, Germany

关键词: Glucose transport;    IAPS-Forskolin;    Insulin-regulated glucose transporter GLUT4;    ATB-BMPA;    2-N4-(1-azi-2;    2;    2-trifluoroethyl)benzoyl-1;    3-bis(d-mannosyloxy)-2-propylamine;    [125I]IAPS-forskolin;    3-[125I]-Iodo-4-azidophenetyl-amido-7-O-succinyldeacetyl-forskolin;    GLUT1;    erythrocyte/brain-type glucose transporter;    GLUT4;    adipocyte/muscle-type glucose transporter;    PMSF;    phenylmethylsulfonylfluoride;    SDS-PAGE;    sodium dodecylsulfate polyacrylamide gel electrophoresis;   

DOI  :  10.1016/0014-5793(94)00558-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Six tyrosine residues (Y28, Y143, Y292, Y293, Y308, Y432¹) which are conserved in all mammalian glucose transporters were substituted for phenylalanine by site-directed mutagenesis, and mutant glucose transporters were transiently expressed in COS-7 cells. Glucose transport activity as assessed by reconstitution of the solubilized transporters into lecithin liposomes was reduced by 70% in the mutant Y143F and appeared to be abolished in Y293F, but was not affected by substitution of Y28, Y292, Y308 and Y432. In contrast, covalent binding of the photolabel ¹²⁵IAPS-forskolin was normal in all mutants. Stable expression of the mutants Y143F, Y293F, and Y292F in LTK cells yielded identical results. These data indicate that only two of the 6 conserved helical tyrosines residues, located in helices 4 and 7, are essential for full activity, but not for IAPS-forskolin binding of the GLUT4.

【 授权许可】

Unknown