GAD65

GAD65 (Glutamate Decarboxylase 65) is an enzyme that plays a crucial role in the central nervous system by converting glutamate to gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the brain. GAD65 is one of the two isoforms of the enzyme glutamate decarboxylase, the other being GAD67. These isoforms are encoded by different genes and have distinct cellular localizations and functions.

Function

GAD65 is primarily found in the pancreatic beta cells and the nerve terminals of the central nervous system. It is involved in the synthesis of GABA, which is essential for regulating neuronal excitability and maintaining the balance between excitation and inhibition in the brain. GAD65 is anchored to the membrane of synaptic vesicles and is activated in response to increased neuronal activity.

Clinical Significance

GAD65 is a major autoantigen in type 1 diabetes mellitus (T1DM). Autoantibodies against GAD65 are commonly found in patients with T1DM and are used as a marker for the diagnosis and prediction of the disease. Additionally, GAD65 autoantibodies are also associated with other autoimmune conditions such as stiff-person syndrome and autoimmune polyendocrine syndromes.

Genetic Information

The gene encoding GAD65 is located on chromosome 10 in humans. Mutations or polymorphisms in the GAD65 gene can affect the enzyme's function and have been linked to various neurological and autoimmune disorders.

Related Proteins

• GAD67: Another isoform of glutamate decarboxylase, encoded by a different gene and primarily found in the cytosol.
• GABA: The primary inhibitory neurotransmitter synthesized by GAD65.

See Also

• Type 1 diabetes mellitus
• Stiff-person syndrome
• Autoimmune polyendocrine syndromes
• Glutamate decarboxylase
• Gamma-aminobutyric acid