Standard Article

Role of Monosaccharide Transport Proteins in Carbohydrate Assimilation, Distribution, Metabolism, and Homeostasis

  1. Anthony J. Cura,
  2. Anthony Carruthers

Published Online: 1 APR 2012

DOI: 10.1002/cphy.c110024

Comprehensive Physiology

Comprehensive Physiology

How to Cite

Cura, A. J. and Carruthers, A. 2012. Role of Monosaccharide Transport Proteins in Carbohydrate Assimilation, Distribution, Metabolism, and Homeostasis. Comprehensive Physiology. 2:863–914.

Author Information

  1. Department of Biochemistry & Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts

Publication History

  1. Published Online: 1 APR 2012

Abstract

The facilitated diffusion of glucose, galactose, fructose, urate, myoinositol, and dehydroascorbic acid in mammals is catalyzed by a family of 14 monosaccharide transport proteins called GLUTs. These transporters may be divided into three classes according to sequence similarity and function/substrate specificity. GLUT1 appears to be highly expressed in glycolytically active cells and has been coopted in vitamin C auxotrophs to maintain the redox state of the blood through transport of dehydroascorbate. Several GLUTs are definitive glucose/galactose transporters, GLUT2 and GLUT5 are physiologically important fructose transporters, GLUT9 appears to be a urate transporter while GLUT13 is a proton/myoinositol cotransporter. The physiologic substrates of some GLUTs remain to be established. The GLUTs are expressed in a tissue specific manner where affinity, specificity, and capacity for substrate transport are paramount for tissue function. Although great strides have been made in characterizing GLUT-catalyzed monosaccharide transport and mapping GLUT membrane topography and determinants of substrate specificity, a unifying model for GLUT structure and function remains elusive. The GLUTs play a major role in carbohydrate homeostasis and the redistribution of sugar-derived carbons among the various organ systems. This is accomplished through a multiplicity of GLUT-dependent glucose sensing and effector mechanisms that regulate monosaccharide ingestion, absorption, distribution, cellular transport and metabolism, and recovery/retention. Glucose transport and metabolism have coevolved in mammals to support cerebral glucose utilization. © 2012 American Physiological Society. Compr Physiol 2:863-914, 2012.