transportadores de glucosa

Archivos Venezolanos de Farmacología y Terapéutica
Sociedad Venezolana de Farmacología Clínica y Terapéutica
mvelasco@reacciun.ve, veloscom@cantv.net

ISSN (Versión impresa): 0798-0264
VENEZUELA

2007
Valmore Bermúdez / Fernando Bermúdez / Nailet Arraiz / Elliuz Leal / Sergia Linares /
Edgardo Mengual / Lisney Valdelamar / Moisés Rodríguez / Hamid Seyfi / Anilsa
Amell / Marisol Carrillo/ Carlos Silva / Alejandro Acosta / Johnny Añez / Carla Andara
/ et-al
BIOLOGÍA MOLECULAR DE LOS TRANSPORTADORES DE GLUCOSA:
CLASIFICACIÓN, ESTRUCTURA Y DISTRIBUCIÓN
Archivos Venezolanos de Farmacología y Terapéutica, año/vol. 26, número 002
Sociedad Venezolana de Farmacología Clínica y Terapéutica
Caracas, Venezuela
pp. 76-86

Red de Revistas Científicas de América Latina y el Caribe,España y Portugal
Universidad Autónoma del Estado de México
http://redalyc.uaemex.mx

Biología molecular de los transportadores
de glucosa: clasificación, estructura y distribución

Valmore Bermúdez, Fernando Bermúdez, Nailet Arraiz, Elliuz Leal, Sergia Linares, Edgardo Mengual, Lisney Valdelamar, Moisés Rodríguez, Hamid Seyfi, Anilsa Amell,
Marisol Carrillo, Carlos Silva, AlejandroAcosta, Johnny Añez, Carla Andara, Verónica Angulo, Gabriela Martins.
Universidad del Zulia. Facultad de Medicina. Centro de Investigaciones
Endocrino–Metabólicas “Dr. Félix Gómez”. Maracaibo, Estado Zulia
e-mail: fago@medscape.com

Aceptado: 03/08/2007

Resumen

Abstract

Hexosas como la glucosa, galactosa y fructosa cumplen
funciones importantes en las células eucarióticas. Estasmoléculas son incapaces de difundir directamente a través
de las membranas celulares por lo que requieren proteínas
transportadoras especializadas para entrar al interior celular.
Dichas biomoléculas pertenecen a un grupo de transportadores constituida por 2 familias de proteínas: la familia de los
Glut´s (del inglés Glucose Transporters) y la familia de los
co-transportadores de sodio y glucosa.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. Each of thetransporters has different
affinities for glucose and the other hexoses, which largely dictates their function. The hexose transporters are large integral
membrane proteins. Based on the deduced amino acid sequences of their cloned cDNAs, they have similar structures,
consisting of 12 or 14 membrane-spanning regions with cytoplasmic C-terminal and N-terminal tails. Also, they all appear
to beglycosylated on one of the extracellular loops. Transport
of sugars across membranes appears to result from a series
of conformational changes which “flips” the transporter between alternate states with the substrate binding site either
facing the extracellular or cytoplasmic side of the membrane.
Transport in either direction is thus possible, depending on
relative substrate concentrationson either side of the membrane. The original protein, GLUT1, was identified in molecular term’s 12 years ago. In the subsequent 15 years, a family of
related transporters was identified (GLUTs 1-14). The impact
of these discoveries is better realized when we list a sample of
the processes that utilize different members of the GLUT family: control of glycemia; insulin dependent glucoseutilization;
transport pathways in brain neurons and glia; mechanisms of
glucose and fructose uptake in the intestinal track; reabsorption of glucose in kidney tubules and jejunum; maturation of
transporters during lactation and weaning; sensing of glucose
levels by the pancreas and the liver; control of glucose uptake
in high fat feeding; glucose uptake in response to exercise,
adaptive response...