MTMR2

The MTMR2 gene provides instructions for making a protein that is a member of the myotubularin family. Members of this family help remove a phosphate group, a cluster of one phosphorus and three oxygen atoms, from other substances. Removal of a phosphate group modifies the activity of a substance. Based on the action of removing phosphate groups, these proteins are called phosphatases.

The MTMR2 protein modifies substances that act as chemical messengers. These messengers relay signals from receptors on the cell surface to specific compartments inside the cell, through a process called signal transduction. Signal transduction helps cells respond to their environment, for example, by dividing or maturing to take on specialized functions. The MTMR2 protein modifies a chemical messenger that helps regulate processes such as the transport of fats (lipids) and proteins within the cell.

Charcot-Marie-Tooth disease - caused by mutations in the MTMR2 gene

Researchers have identified several MTMR2 mutations that cause a form of Charcot-Marie-Tooth disease known as type 4B1. These mutations alter the structure of the MTMR2 protein by producing a protein that is abnormally small or by changing one of the building blocks (amino acids) used to make the protein. The altered structure probably impairs the protein's ability to modify messenger molecules, which could disrupt the transport of lipids and proteins.

It is unclear how MTMR2 mutations cause type 4B1 Charcot-Marie-Tooth disease. Scientists suggest that specialized cells, called Schwann cells, are particularly vulnerable when the MTMR2 protein is impaired. Schwann cells produce myelin, a protective substance that covers nerves and promotes the rapid transmission of nerve impulses. Schwann cells use large amounts of lipids and proteins to make myelin, relying on efficient cellular transport of these substances. Disrupted cellular transport could affect myelin production, altering the transmission of nerve impulses. A disturbance in nerve transmission is a sign of type 4B1 Charcot-Marie-Tooth disease.