Jung C Y
Biophysics Laboratory, VA Medical Center, Buffalo, NY 14215, USA.
Exp Physiol. 1998 Mar;83(2):267-73. doi: 10.1113/expphysiol.1998.sp004112.
The cellular uptake of glucose catalysed by the facilitated glucose transporter (GLUT) family is further regulated by metabolites and hormones, most importantly by insulin. All of the six isoforms known in this family possess a large cytoplasmic domain of divergent amino acid sequence. A body of evidence indicates that this domain is important for GLUT regulation. Exactly how this domain participates in the regulation, however, is not known. A likely possibility is that a specific cellular protein interacts with GLUT at this domain, and thus modulates the function. This putative, glucose transporter binding protein (GTBP) may be an enzyme, or a non-enzymic adaptor or docking protein. Indeed, we have identified several cellular proteins that bind to the cytoplasmic domain of GLUT proteins; these include glyceraldehyde-3-phosphate dehydrogenase, glucokinase, GTBP70, GTBP85, GTBP28 and L-3-hydroxyacyl-CoA dehydrogenase. Some of these GLUT-GTPB interactions are functionally coupled. Whether any of these interactions actually participates in the insulin-induced GLUT regulation is yet to be determined.
易化葡萄糖转运蛋白（GLUT）家族催化的葡萄糖细胞摄取会受到代谢物和激素的进一步调节，其中最重要的是胰岛素。该家族已知的六种同工型都拥有一个由不同氨基酸序列组成的大细胞质结构域。大量证据表明，该结构域对GLUT的调节很重要。然而，这个结构域究竟是如何参与调节的尚不清楚。一种可能的情况是，一种特定的细胞蛋白在这个结构域与GLUT相互作用，从而调节其功能。这种假定的葡萄糖转运蛋白结合蛋白（GTBP）可能是一种酶，或者是一种非酶性衔接蛋白或对接蛋白。事实上，我们已经鉴定出几种与GLUT蛋白细胞质结构域结合的细胞蛋白；这些蛋白包括甘油醛-3-磷酸脱氢酶、葡萄糖激酶、GTBP70、GTBP85、GTBP28和L-3-羟基酰基辅酶A脱氢酶。其中一些GLUT-GTPB相互作用在功能上是耦合的。这些相互作用中是否有任何一种实际参与了胰岛素诱导的GLUT调节还有待确定。
