Human Ermin (hErmin), a new oligodendrocyte-specific cytoskeletal protein related to epileptic seizure.

During the maturation of oligodendrocytes, cells are characterized by their morphological changes such as the number of process extensions and sheet-like membranes. This process relies critically on cytoskeleton rearrangement, but the molecular mechanisms underlying this are still unclear. Here, we identify human Ermin (hErmin), a novel cytoskeletal molecule that is expressed exclusively in oligodendrocytes in human brain, as a regulator of cytoskeleton rearrangement. In vitro, full-length hErmin expression, but not its truncated mutants lacking the actin-binding domain, promote arborization of cultured COS-7 cells and induce marked changes in cell morphology. The most important is that expression of hErmin in specimens of epileptic patients is much lower than that of control, implying that hErmin may be involved in epileptogenic process. These findings suggest a role for hErmin as a novel cytoskeleton-related oligodendroglial protein in human brain myelination and human epileptogenesis, and provide new evidence for the relationship between oligodendrocytes and epilepsy.