Myelin basic protein

Myelin basic protein (MBP) is a protein believed to be important in the process of myelination of nerves in the central nervous system (CNS).

MBP was initially sequenced in 1979 after isolation from myelin membranes. Since that time, knockout mice deficient in MBP have been developed which showed decreased amounts of CNS myelination and a progressive disorder characterized by tremors, seizures, and early death. The gene for MBP is on chromosome 18; the protein localizes to the CNS and to various cells of the hematopoietic system.

The pool of MBP in the central nervous system is very diverse, with several splice variants being expressed and a large number of post-translational modifications on the protein, which include phosphorylation, methylation, deamidation and citrullination.

Role in disease
Interest in MBP has centered on its role in demyelinating diseases, particularly multiple sclerosis (MS). Several studies have shown a role for antibodies against MBP in the pathogenesis of MS. Some studies have linked a genetic predisposition to MS to the MBP gene, though a majority have not.

Some recent works have shown that administration of MBP artificially increases blood-brain barrier permeability.

MBP is currently being researched as a possible treatment for lethal rabies infection. The administration of MBP increases the permeability of the blood-brain barrier (BBB) allowing immune cells to enter the brain, the primary site of rabies virus replication. In a study of mice infected with Silver-haired bat rabies virus (SHBRV) the mortality rate of mice treated with MBP improved 20%-30% over the untreated control group. It is significant to note that healthy uninfected mice treated with MBP showed an increase in mortality rate between 0% and 40%.