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Ganglioside
 
 
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Ganglioside is a compound composed of a glycosphingolipid (ceramide
Ceramide

Ceramides are a family of lipid molecules. A ceramide is composed of sphingosine and a fatty acid. Ceramides are found in high concentrations within the cell membrane of cells....
 and oligosaccharide
Oligosaccharide

An oligosaccharide is a saccharide polymer containing a small number of component sugars, also known as simple sugars. The name derived from the Greek oligos, meaning "a few"....
) with one or more sialic acid
Sialic acid

Sialic acid is a generic term for the N- or O-substituted derivatives of neuraminic acid, a monosaccharide with a nine-carbon backbone....
s (AKA n-acetylneuraminic acid
N-Acetylneuraminic acid

N-Acetylneuraminic acid is the predominant sialic acid found in mammalian cells.This negatively charged residue is found in complex glycans on mucins and glycoproteins found at the cell membrane....
, NANA) linked on the sugar chain. The 60+ known gangliosides differ mainly in the position and number of NANA residue
Residue (chemistry)

In chemistry, residue refers to the material remaining after a distillation or an evaporation, or to a portion of a larger molecule, such as a methyl group....
s.

It is a component of the cell plasma membrane that modulates cell signal transduction events. It appears that they concentrate in lipid raft
Lipid raft

A lipid raft is a cholesterol-enriched microdomain in cell membranes....
s.

They have recently been found to be highly important in immunology
Immunology

Immunology is a broad branch of biomedical science science that covers the study of all aspects of the immune system in all organisms. It deals with, among other things, the physiology functioning of the immune system in states of both health and disease; malfunctions of the immune system in immunological disorders ; the physical, chemical an...
.






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Encyclopedia


Ganglioside is a compound composed of a glycosphingolipid (ceramide
Ceramide

Ceramides are a family of lipid molecules. A ceramide is composed of sphingosine and a fatty acid. Ceramides are found in high concentrations within the cell membrane of cells....
 and oligosaccharide
Oligosaccharide

An oligosaccharide is a saccharide polymer containing a small number of component sugars, also known as simple sugars. The name derived from the Greek oligos, meaning "a few"....
) with one or more sialic acid
Sialic acid

Sialic acid is a generic term for the N- or O-substituted derivatives of neuraminic acid, a monosaccharide with a nine-carbon backbone....
s (AKA n-acetylneuraminic acid
N-Acetylneuraminic acid

N-Acetylneuraminic acid is the predominant sialic acid found in mammalian cells.This negatively charged residue is found in complex glycans on mucins and glycoproteins found at the cell membrane....
, NANA) linked on the sugar chain. The 60+ known gangliosides differ mainly in the position and number of NANA residue
Residue (chemistry)

In chemistry, residue refers to the material remaining after a distillation or an evaporation, or to a portion of a larger molecule, such as a methyl group....
s.

It is a component of the cell plasma membrane that modulates cell signal transduction events. It appears that they concentrate in lipid raft
Lipid raft

A lipid raft is a cholesterol-enriched microdomain in cell membranes....
s.

They have recently been found to be highly important in immunology
Immunology

Immunology is a broad branch of biomedical science science that covers the study of all aspects of the immune system in all organisms. It deals with, among other things, the physiology functioning of the immune system in states of both health and disease; malfunctions of the immune system in immunological disorders ; the physical, chemical an...
. Natural and semisynthetic gangliosides are considered possible therapeutics for neurodegenerative disorders.

Gangliosides are more complex glycosphingolipids in which oligosaccharide chains containing N-acetylneuraminic acid (NeuNAc) are attached to a ceramide. NeuNAc, an acetylated derivative of the carbohydrate sialic acid, makes the head groups of Gangliosides anionic. NB: the M in GM2 stands for monosialo, i.e., one NeuNAc residue. GM2 is the second monosialo ganglioside characterized, thus the subscript 2. Their structural diversity results from variation in the composition and sequence of the sugar residues. In all Gangliosides, the ceramide is linked through its C-1 to a ß-glucosyl residue, which, in turn, is bound to a ß-galactosyl residue.

The name ganglioside was first applied by the German scientist Ernst Klenk in 1942 to lipids newly isolated from ganglion cells
Ganglion cell

A retinal ganglion cell is a type of neuron located near the inner surface of the retina of the eye. It receives visual information from photoreceptor cells via two intermediate neuron types: Bipolar cell of the retinas and amacrine cells....
 of brain

Location


They are present on cell surfaces, with the 2 hydrocarbon chains of the ceramide moiety embedded in the plasma membrane and the oligosaccharides on the extracellular surface. They are found predominantly in the nervous system where they constitute 6% of all phospholipids.

They are involved in diverse roles including cell-to-cell contact, ion conductance, and receptor.

Function


Gangliosides, glycosphingolipids, and glycoproteins found on the surface of oligosaccharide provide cells with distinguishing surface markers that can serve in cellular recognition and cell-to-cell communication. Structures similar to the ABO blood group antigens on the surface of human cells can be oligosaccharide components of glycosphingolipids in addition to being linked to proteins to form glycoproteins.

Common gangliosides

  • One NANA
    N-Acetylneuraminic acid

    N-Acetylneuraminic acid is the predominant sialic acid found in mammalian cells.This negatively charged residue is found in complex glycans on mucins and glycoproteins found at the cell membrane....
     ("M")
    • GM1
      GM1

      GM1 the "prototype" ganglioside, is a member of the ganglio series of gangliosides which contain one sialic acid residue. GM1 has important physiological properties and impacts Neuroplasticity and repair mechanisms, and the release of neurotrophins in the brain....
    • GM2
    • GM3


  • Two NANAs ("D")
    • GD1a
    • GD1b
    • GD2
      GD2

      GD2 is a disialoganglioside expressed on tumors of neuroectodermal origin, including human neuroblastoma and melanoma, with highly restricted expression on normal tissues, principally to the cerebellum and peripheral nerves in humans....
    • GD3


  • Three NANAs ("T")
    • GT1b


  • Four NANAs ("Q")
    • GQ1


structures of the common gangliosides


GM2-1 = aNeu5Ac(2-3)bDGalp(1-?)bDGalNAc(1-?)bDGalNAc(1-?)bDGlcp(1-1)Cer
GM3 = aNeu5Ac(2-3)bDGalp(1-4)bDGlcp(1-1)Cer
GM2,GM2a(?) = bDGalpNAc(1-4)[aNeu5Ac(2-3)]bDGalp(1-4)bDGlcp(1-1)Cer
GM2b(?) = aNeu5Ac(2-8)aNeu5Ac(2-3)bDGalp(1-4)bDGlcp(1-1)Cer
GM1,GM1a = bDGalp(1-3)bDGalNAc[aNeu5Ac(2-3)]bDGalp(1-4)bDGlcp(1-1)Cer
asialo-GM1,GA1 = bDGalp(1-3)bDGalpNAc(1-4)bDGalp(1-4)bDGlcp(1-1)Cer
asialo-GM2,GA2 = bDGalpNAc(1-4)bDGalp(1-4)bDGlcp(1-1)Cer
GM1b = aNeu5Ac(2-3)bDGalp(1-3)bDGalNAc(1-4)bDGalp(1-4)bDGlcp(1-1)Cer
GD3 = aNeu5Ac(2-8)aNeu5Ac(2-3)bDGalp(1-4)bDGlcp(1-1)Cer
GD2 = bDGalpNAc(1-4)[aNeu5Ac(2-8)aNeu5Ac(2-3)]bDGalp(1-4)bDGlcp(1-1)Cer
GD1a = aNeu5Ac(2-3)bDGalp(1-3)bDGalNAc(1-4)[aNeu5Ac(2-3)]bDGalp(1-4)bDGlcp(1-1)Cer
GD1alpha = aNeu5Ac(2-3)bDGalp(1-3)bDGalNAc(1-4)[aNeu5Ac(2-6)]bDGalp(1-4)bDGlcp(1-1)Cer
GD1b = bDGalp(1-3)bDGalNAc(1-4)[aNeu5Ac(2-8)aNeu5Ac(2-3)]bDGalp(1-4)bDGlcp(1-1)Cer
GT1a = aNeu5Ac(2-8)aNeu5Ac(2-3)bDGalp(1-3)bDGalNAc(1-4)[aNeu5Ac(2-3)]bDGalp(1-4)bDGlcp(1-1)Cer
GT1,GT1b = aNeu5Ac(2-3)bDGalp(1-3)bDGalNAc(1-4)[aNeu5Ac(2-8)aNeu5Ac(2-3)]bDGalp(1-4)bDGlcp(1-1)Cer
OAc-GT1b = aNeu5Ac(2-3)bDGalp(1-3)bDGalNAc(1-4)aXNeu5Ac9Ac(2-8)aNeu5Ac(2-3)]bDGalp(1-4)bDGlcp(1-1)Cer
GT1c = bDGalp(1-3)bDGalNAc(1-4)[aNeu5Ac(2-8)aNeu5Ac(2-8)aNeu5Ac(2-3)]bDGalp(1-4)bDGlcp(1-1)Cer
GT3 = aNeu5Ac(2-8)aNeu5Ac(2-8)aNeu5Ac(2-3)bDGal(1-4)bDGlc(1-1)Cer
GQ1b = aNeu5Ac(2-8)aNeu5Ac(2-3)bDGalp(1-3)bDGalNAc(1-4)[aNeu5Ac(2-8)aNeu5Ac(2-3)]bDGalp(1-4)bDGlcp(1-1)Cer
GGal = aNeu5Ac(2-3)bDGalp(1-1)Cer

where
aNeu5Ac = 5-acetyl-alpha-neuraminic acid
aNeu5Ac9Ac = 5,9-diacetyl-alpha-neuraminic acid
bDGalp = beta-D-galactopyranose
bDGalpNAc = N-acetyl-beta-D-galactopyranose
bDGlcp = beta-D-glucopyranose
Cer = ceramide (general N-acylated sphingoid)

Pathobiology


Gangliosidoses


Mutations in genes coding for enzymes of ganglioside metabolism cause severe lipid storage diseases called gangliosidoses
Gangliosidosis

Gangliosidosis is a lipid storage disorder caused by the accumulation of lipids known as gangliosides. There are two distinct genetic causes of the disease....
, that encomprise gangliosidosis GM1 and gangliosidosis GM2 (Tay-Sachs Disease
Tay-Sachs disease

Tay-Sachs disease is a genetic disorder, fatal in its most common variant known as Infantile Tay-Sachs disease. TSD is inherited in an autosomal recessive pattern....
 and Sandhoff disease
Sandhoff disease

Sandhoff disease, also called Hexosaminidase A and B deficiency, is an autosomal recessive lysosomal storage disorder that affects lipid storage and causes progressive destruction of the central nervous system....
).

The non-functioning beta-galactosidase (GM1) or hexosaminidase (GM2) causes the accumulation of gangliosides in lysososmes (lysosomal storage disease
Lysosomal storage disease

Lysosomal storage diseases are a group of approximately 40 rare inherited metabolic disorders that result from defects in lysosome function. Lysosomal storage diseases result when a specific organelle in the body's cells ? the lysosome ? malfunctions....
) of several cells (macrophages, neurons), disturbing their functions.

Miscellaneous


Ganglioside are also involved in several diseases:

  • Haemagglutinin of Influenza virus exploits certain gangliosides to enter and infect the cells expressing them.
  • Tay-Sachs Disease
    Tay-Sachs disease

    Tay-Sachs disease is a genetic disorder, fatal in its most common variant known as Infantile Tay-Sachs disease. TSD is inherited in an autosomal recessive pattern....
     involves accumulation of gangliosides due to a non functioning B-N-acetyl hexosaminidase.
  • Guillain-Barré syndrome
    Guillain-Barré syndrome

    Guillain-Barr? syndrome is an acute inflammatory demyelinating polyneuropathy , an Autoimmune Disease disease affecting the peripheral nervous system, usually triggered by an acute infectious process....
  • Cholera toxin
    Cholera toxin

    Cholera toxin is a protein complex secreted by the bacterium Vibrio cholerae. CTX is responsible for the harmful effects of cholera infection....
  • Clostridium tetani
    Clostridium tetani

    Clostridium tetani is a rod-shaped, anaerobic bacterium of the genus Clostridium. Like other Clostridium species, it is Gram-positive, and its appearance on a gram stain resembles tennis rackets or drumsticks....


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