AsianScientist (Jul. 4, 2018) – In a study published in the Proceedings of the National Academy of Sciences, a research group in China has obtained a high-resolution image of the glucose transport (GLUT) 1 protein, a ubiquitously-expressed membrane protein responsible for the constant uptake of glucose in many tissues.
Cells depend on glucose as a primary source of energy, and they take up glucose through channels known as glucose transporters. While there are many different types of GLUT proteins, GLUT1 is the major channel for glucose passage into cells. Scientists first obtained the crystal structure of human GLUT1 at 3.2 angstrom resolution in 2014.
However, the way GLUT1 is organized on the cell membrane was unclear. According to the protein layer-lipid-protein island membrane model, a dense protein layer forms on the external side of the membrane, while dispersed protein microdomains form on the internal side.
In the present study, researchers led by Professor Wang Hongda of the Changchun Institute of Applied Chemistry, and Professor Xiong Wenyong from the Kunming Institute of Botany, investigated the distribution and assembly of GLUT1 at nanometer resolution using direct stochastic optical reconstruction microscopy (dSTORM).
They found that the transporters formed clusters with an average diameter of ~250 nm on the cell membrane. There was a precise spatial association between GLUT1 and lipid rafts. The researchers also showed that the actin cytoskeleton and N-glycosylation—a specific type of protein modification—play important roles in forming the GLUT1 clusters, and the lipid raft helps to stabilize them.
The results suggested a potential association between the distribution and activation of GLUT1. The team’s work may pave the way for a better understanding of the molecular mechanism of GLUT clustering and glucose uptake.
The article can be found at: Yan et al. (2018) Mechanistic Insights Into Glut1 Activation and Clustering Revealed by Super-resolution Imaging.
Source: Chinese Academy of Sciences; Photo: Shutterstock.
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