POMT2

Protein O-mannosyl-transferase 2 (POMT2) is an enzyme that in humans is encoded by the POMT2 gene. This enzyme is involved in the process of protein glycosylation, specifically the O-mannosylation of proteins, which is a critical post-translational modification.

Function

POMT2, along with POMT1, forms a complex that catalyzes the transfer of mannose from dolichol-phosphate-mannose to serine or threonine residues on proteins. This process is essential for the proper functioning of several proteins, particularly those involved in the development and maintenance of muscle tissue and the central nervous system.

Clinical Significance

Mutations in the POMT2 gene have been associated with a spectrum of muscular dystrophies known as congenital muscular dystrophies (CMDs). These include Walker-Warburg syndrome, muscle-eye-brain disease, and other forms of CMD characterized by dystroglycanopathy. These conditions are often severe and can involve muscle weakness, brain malformations, and eye abnormalities.

Genetics

The POMT2 gene is located on chromosome 14 at the q24.3 band. It spans approximately 35 kb and consists of 20 exons. The gene is expressed in various tissues, with higher expression levels observed in the brain and skeletal muscle.

Pathophysiology

The pathophysiological mechanism underlying POMT2-related disorders involves defective glycosylation of alpha-dystroglycan, a protein that plays a crucial role in linking the extracellular matrix to the cytoskeleton. This defective glycosylation impairs the function of alpha-dystroglycan, leading to the clinical manifestations observed in affected individuals.

Research Directions

Current research is focused on understanding the detailed mechanisms of POMT2 function and its interactions with other proteins involved in glycosylation. There is also significant interest in developing therapeutic strategies to correct the glycosylation defects caused by POMT2 mutations.

Also see

• POMT1
• Congenital muscular dystrophy
• Glycosylation
• Dystroglycanopathy