Glucose transporter 1 (Glut1)

Glucose transporter 1 or GLUT1, also known as solute carrier family 2, facilitated glucose transporter member 1.

Encoded by the SLC2A1 gene.

It facilitates the transport of glucose across the plasma membranes of cells.

The SLC2A1 gene encodes a major glucose transporter in the blood-brain barrier.

The encoded protein is found primarily in the cell membrane and on the cell surface.

It can also function as a receptor for human T-cell leukemia virus (HTLV) I and II.

Mutations in this gene can cause: GLUT1 deficiency syndrome 1, GLUT1 deficiency syndrome 2, idiopathic generalized epilepsy 12, dystonia 9, and stomatin-deficient cryohydrocytosis.

Gene location is on Chromosome 1.

GLUT1 was the first glucose transporter characterized.

Encoded by the SLC2 gene and is one of a family of 14 genes encoding GLUT proteins.

The SLC2A1 gene is located on the p arm of chromosome.

RBC energy depends on a constant supply of glucose from the blood plasma, where the glucose concentration is maintained at about 5mM.

Glucose enters the erythrocyte by facilitated diffusion via a specific glucose transporter, at a rate 50,000 times greater than transmembrane diffusion.

It is the glucose transporter of erythrocytes, distinguishing it from related glucose transporters in other tissues.

It is responsible for the basal glucose uptake required to sustain respiration in all cells.

GLUT1 expression in cell membranes are increased by reduced glucose levels and decreased by increased glucose levels.

GLUT1 is also a major receptor for uptake of Vitamin C as well as glucose.

GLUT1 expression occurs in almost all tissues.

GLUT1 expression typically correlating with the rate of cellular glucose metabolism, and is expressed at highest levels in erythrocytes and also in the endothelial cells of barrier tissues such as the blood–brain barrier.

Mutations in the GLUT1 gene are responsible for GLUT1 deficiency or De Vivo disease.

De Vivo disease is a rare autosomal dominant disorder characterized by low CSF glucose concentration, resulting from impaired glucose transport across the blood–brain barrier.

Many mutations in the SLC2A1 cause GLUT1 deficiency syndrome 1.

GLUT1 deficiency syndrome 1 has wide phenotypic variability.

GLUT1 deficiency syndrome can be inherited in either an autosomal recessive or autosomal dominant manner.

In its most severe phenotype GLUT1 deficiency syndrome presents with infantile-onset epileptic encephalopathy associated with delayed development, acquired microcephaly, motor incoordination, and spasticity, confusion, lethargy, sleep disturbance, and headache.

GLUT1 deficiency syndrome has cognitive impairment, ranging from learning disabilities to severe mental retardation.

Other mutations, cause GLUT1 deficiency syndrome 2 (GLUT1DS2), a clinically variable disorder characterized primarily by onset in childhood of paroxysmal exercise-induced dyskinesia.

Dyskinesia involves abnormal involuntary movements.

Some patients may have childhood absence epilepsy, or mental retardation.

GLUT1 deficiency syndrome 2 inheritance is autosomal dominant.

GLUT1 is also a receptor used by the HTLV virus to gain entry into target cells.

Glut1 is a histochemical marker for hemangioma of infancy.

There are two significant types of Glut1 in the brain 45k and 55k.

GLUT1 45k is present on astroglia of neurons.

GLUT1 55k is present on capillaries in brain and is responsible for glucose transport across blood brain barrier.

A deficiency of Glut155k causes low level of glucose in CSF which may manifest as convulsions.

GLUT1 inhibitor, DERL3, that is often methylated in colorectal cancer.

The small molecule inhibitor Fasentin of the intracellular domain of GLUT1 prevents glucose uptake.

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