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Insulin‐dependent translocation of the small GTP‐binding protein rab3C in cardiac muscle: studies on insulin‐resistant Zucker rats
Author(s) -
Uphues Ingo,
Chern Yijuang,
Eckel Jürgen
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)01315-6
Subject(s) - glut4 , insulin , medicine , endocrinology , cardiac muscle , gtp' , glucose transporter , microsome , chromosomal translocation , cell fractionation , stimulation , biology , chemistry , biochemistry , membrane , in vitro , enzyme , gene
The failure of insulin‐regulated recruitment of the GLUT4 glucose transporter in cardiac muscle of obese Zucker rats is associated with alterations of the subcellular distribution of the small‐molecular‐mass GTP‐binding protein rab4A. Here, we show by subcellular fractionation and Western blotting a translocation of the small‐molecular‐mass GTP‐binding protein rab3C from microsomal membranes to plasma membranes in lean control rats following in vivo insulin stimulation. However, in cardiac muscle of obese animals no significant effect of the hormone on the subcellular distribution of rab3C was observed. In GLUT4‐enriched membrane vesicles, obtained from cardiac microsomes of the obese group as well as of lean controls, rab3C was not detectable. It is suggested that the altered behaviour of rab3C may contribute to an impaired trafficking of GLUT4 in the insulin‐resistant state.