Year: 2014
Type: article
Abstract: Glucose is the main source of metabolic energy for various cellular functions, and thus plays a central role in supporting intermediary metabolism and cellular homeostasis.Since plasma membrane is impermeable to glucose, its cellular uptake is mediated by two distinct processes via specific glucose transporter proteins that belong to the family of solute carriers (SLC); the SLC2 family members, GLUTs (glucose transporters), are sodium-independent facilitators of the glucose transport, whereas the SLC5 family members, SGLTs (sodium and glucose transporters) mediate the secondary-active sodium-glucose cotransport.Until now, 14 GLUTs and 12 SGLTs isoforms have been identified in humans of which 5 GLUTs and none SGLTs were detected in the mammalian blood cells.Detailed physiological function, precise mechanism of transport, substrates affinity, exact three-dimensional structures, and a precise tissue distribution of most GLUTs in various mammalian organs, including blood, have been poorly explored.In this review we will focus on GLUTs in the mammalian blood cells, where the data on their expression and functional roles are contradictory or largely missing.Since many GLUTs are associated with diabetes, and are up-regulated in cancers, it is undoubtedly important to further investigate GLUTs expression in different organs/tissues, including the blood cells.Understanding the complexity of glucose homeostasis that includes knowledge about tissue distribution and function of GLUTs, as well as the signaling pathways that regulate glucose metabolism, may help to develop new therapeutic strategies to target specific diseases, such as diabetes mellitus, some autoimmunity diseases, and cancer. INTRoduCTIoNI n the mammalian cells, glucose is the key source of metabolic energy used in various functions.Metabolic energy that was stored in ATP is generated by degradation of glucose through the processes of glycolysis and citric acid cycle.As a metabolic substrate, glucose is also used for synthesis of glycerol and non-essential amino acids, which represent precursors in synthesis of lipids and proteins (1).Because of the prevalent role of glucose in cellular metabolism, one can ask the following question: why is glucose, and not some other monosaccharide, such as fructose, a preferred source of energy in the most of living organisms?The answer could be partially attributed to widespread availability of glucose in the environment, and partially could be explained by the evolutionary-developed protection from the toxicity of other hexoses; in comparison to other hexoses, glucose has a lower tendency to react nonspecifically with amino groups in proteins and form the advanced glycation end products (AGEs) through the process of glycation.Glycation is non-enzymatic post-translational modification of proteins which is ini-
Authors: Ivana Vrhovac, Davorka Breljak
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2098956240