glucose-6-phosphatase catalytic subunit
The G6PC gene provides instructions for making an enzyme called glucose 6-phosphatase. This enzyme is found on the membrane of the endoplasmic reticulum, which is a structure inside cells that is involved in protein processing and transport. Glucose 6-phosphatase works together with the glucose 6-phosphate translocase protein (produced from the SLC37A4 gene) to break down a type of sugar molecule called glucose 6-phosphate. The breakdown of this molecule produces the simple sugar glucose, which is the primary source of energy for most cells in the body. The glucose 6-phosphatase enzyme is expressed (active) in the liver, kidneys, and intestines, and is the main regulator of glucose production in the liver.
At least 85 mutations in the G6PC gene have been found to cause glycogen storage disease type Ia (GSDIa). Most of these mutations change single protein building blocks (amino acids) in the glucose 6-phosphatase enzyme. Some specific mutations are seen more frequently in certain ethnic or racial groups. Mutations in the G6PC gene impair the function of the glucose 6-phosphatase enzyme. When this enzyme is not functioning normally, glucose 6-phosphate is not broken down and glucose is not produced. Glucose 6-phosphate that is not broken down to glucose is converted to fat and glycogen, a complex sugar that is stored within cells. Too much fat and glycogen stored within a cell can be toxic. This buildup damages organs and tissues throughout the body, particularly the liver and kidneys, leading to the signs and symptoms of GSDIa.
- glucose-6-phosphatase alpha
- glucose-6-phosphatase, catalytic subunit