The encoded protein is found primarily in the cell membrane and on the cell surface, where it can also function as a receptor for human T-cell leukemia virus HTLV I and II. GLUT1 accounts for 2 percent of the protein in the plasma membrane of erythrocytes. GLUT1, found in the plasma membrane of erythrocytes, is a classic example of a uniporter. After glucose is transported into the erythrocyte, it is rapidly phosphorylated, forming glucosephosphate, which cannot leave the cell.
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Transportadores de glicose. Ubiratan Fabres Machado. Glucose, the main source of energy in the cell, is transported in most cells through facilitated diffusion, by the transporter proteins present in the plasma membrane.
Physiopathological changes in glucose transport started to be analysed through transporters with a view to future preventive or therapeutic approaches. In familial renal glycosuria, the participation of SGLT2 and SGLT1 seems to be fundamental, either by loss of transport capacity or by decrease in the transporter affinity. De Vivo's syndrome, described in convulsive infants with hypoglycorrachia during normoglycaemia, has been attributed to a reduction in the GLUT1 content in endothelial cells at the blood-brain barrier.
Extensive studies have been conducted to assess the role of GLUT4 in changes related to insulin sensitiveness, such as diabetes mellitus type 2 DM2. These studies have revealed that, in DM2, the GLUT4 content is drastically reduced, playing an important role in insulin resistance.
In obesity, the GLUT4 content is not diminished providing that insulin sensitiveness is preserved. It is plausible to propose that the modulation of GLUT4 is triggered by a combination of factors indicating cellular sensitiveness to insulin. A topologia dos transportadores de glicose GLUTs inicialmente proposta por Mueckler e cols 2 para o GLUT 1, e posteriormente confirmada para as outras isoformas 12 , e pode ser vista na Figura 1.
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Biología molecular de los transportadores de glucosa: clasificación, estructura y distribución
Publication date Print : Escuela de Medicina. Igualmente todos parecen estar glicosilados en alguna de sus asas extracelulares. Hexoses like glucose, galactose and fructose serve as basic fuel molecules for eucaryotic cells. These molecules are unable to diffuse across cellular membranes, and require transporter proteins for entry into and exit from cells. Three distinct groups of hexose transporters have been identified and classified based on their dependence on cellular energy and its chemistry structure.
2007, Número 2